U
C
Version: 3.0 beta - June 25, 2015
Contents
Introduction
About . . . . . . . . . . .
Disclaimer . . . . . . . . .
Software disclaimer .
Limitation of liability
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5
5
6
6
6
Input
General information . . . . . . . . . . . . . .
Structure . . . . . . . . . . . . . . . . .
Abbreviations . . . . . . . . . . . . . .
Functions & parameters . . . . . . . . .
Binary and ASCII output . . . . . . . .
Input handling . . . . . . . . . . . . . . . .
*END . . . . . . . . . . . . . . . . . .
*INCLUDE . . . . . . . . . . . . . . . .
*INCLUDE BINARY . . . . . . . . . .
*UNIT SYSTEM . . . . . . . . . . . .
Solution control and techniques . . . . . . .
*ANALYSIS BUCKLING EIGENMODE
*ANALYSIS DYNAMIC EIGENMODE .
*ANALYSIS LINEAR STATIC . . . . .
*GPU . . . . . . . . . . . . . . . . . .
*SMS . . . . . . . . . . . . . . . . . .
*SMS CLUSTER . . . . . . . . . . . .
*TIME . . . . . . . . . . . . . . . . . .
Output . . . . . . . . . . . . . . . . . . . .
*OUTPUT . . . . . . . . . . . . . . . .
*OUTPUT ELEMENT . . . . . . . . .
*OUTPUT FORMING . . . . . . . . . .
*OUTPUT NODE . . . . . . . . . . . .
*OUTPUT SENSOR . . . . . . . . . .
Mesh Commands . . . . . . . . . . . . . . .
*ACTIVATE ELEMENTS . . . . . . . .
*COMPONENT BOLT . . . . . . . . .
*COMPONENT BOX . . . . . . . . . .
*COMPONENT CYLINDER . . . . . .
*COMPONENT PIPE . . . . . . . . . .
*COMPONENT SPHERE . . . . . . . .
*MERGE DUPLICATED NODES . . . .
*REFINE . . . . . . . . . . . . . . . . .
*SMOOTH MESH . . . . . . . . . . .
*TRANSFORM MESH CARTESIAN . .
*TRANSFORM MESH CYLINDRICAL .
*TRIM . . . . . . . . . . . . . . . . . .
*WELD . . . . . . . . . . . . . . . . .
Nodes and connectivity . . . . . . . . . . . .
*CHANGE P-ORDER . . . . . . . . . .
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46
IMPETUS Afea Solver v.3.0
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1
*ELEMENT CHEX . . . . . . . . . . . . . .
*ELEMENT CPRISM . . . . . . . . . . . . .
*ELEMENT CTET . . . . . . . . . . . . . .
*ELEMENT QHEX . . . . . . . . . . . . . .
*ELEMENT QPRISM . . . . . . . . . . . . .
*ELEMENT QTET . . . . . . . . . . . . . .
*ELEMENT SHELL . . . . . . . . . . . . . .
*ELEMENT SOLID . . . . . . . . . . . . . .
*NODE . . . . . . . . . . . . . . . . . . . .
*PART . . . . . . . . . . . . . . . . . . . . .
Material properties . . . . . . . . . . . . . . . . .
*EOS GRUNEISEN . . . . . . . . . . . . . .
*EOS POLYNOMIAL . . . . . . . . . . . . .
*EOS TAIT . . . . . . . . . . . . . . . . . .
*MAT CERAMIC . . . . . . . . . . . . . . .
*MAT CREEP . . . . . . . . . . . . . . . . .
*MAT ELASTIC . . . . . . . . . . . . . . . .
*MAT FLUID . . . . . . . . . . . . . . . . .
*MAT FOAM . . . . . . . . . . . . . . . . .
*MAT FORMING . . . . . . . . . . . . . . .
*MAT FORMING R . . . . . . . . . . . . . .
*MAT GRANULAR CAP . . . . . . . . . . .
*MAT HJC CONCRETE . . . . . . . . . . .
*MAT JC . . . . . . . . . . . . . . . . . . .
*MAT JC FIELD . . . . . . . . . . . . . . .
*MAT JH CERAMIC . . . . . . . . . . . . .
*MAT LIBRARY . . . . . . . . . . . . . . .
*MAT METAL . . . . . . . . . . . . . . . . .
*MAT MOONEY RIVLIN . . . . . . . . . . .
*MAT MULTILAYER ORTHOTROPIC . . .
*MAT ORTHOTROPIC . . . . . . . . . . . .
*MAT PWL . . . . . . . . . . . . . . . . . .
*MAT RIGID . . . . . . . . . . . . . . . . .
*MAT USER JS . . . . . . . . . . . . . . . .
*MAT USER X . . . . . . . . . . . . . . . .
*MAT VISCO PLASTIC . . . . . . . . . . .
*PROP DAMAGE BRITTLE . . . . . . . . .
*PROP DAMAGE CL . . . . . . . . . . . . .
*PROP DAMAGE CL ANISOTROPIC . . . .
*PROP DAMAGE IMP . . . . . . . . . . . .
*PROP DAMAGE IMP ISO . . . . . . . . . .
*PROP DAMAGE JC . . . . . . . . . . . . .
*PROP DAMAGE STRAIN . . . . . . . . . .
*PROP THERMAL . . . . . . . . . . . . . .
Initial conditions . . . . . . . . . . . . . . . . . .
*INITIAL DAMAGE RANDOM . . . . . . . .
*INITIAL DAMAGE SURFACE RANDOM . .
*INITIAL MATERIAL DIRECTION . . . . . .
*INITIAL MATERIAL DIRECTION VECTOR
*INITIAL MATERIAL DIRECTION WRAP .
IMPETUS Afea Solver v.3.0
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2
*INITIAL STATE . . . . . . . . . .
*INITIAL STATE HAZ . . . . . . .
*INITIAL STATE WELDSIM . . . .
*INITIAL STRESS FUNCTION . . .
*INITIAL TEMPERATURE . . . . .
*INITIAL VELOCITY . . . . . . . .
Boundary conditions . . . . . . . . . . .
*BC MOTION . . . . . . . . . . . .
*BC SYMMETRY . . . . . . . . . .
*BC TEMPERATURE . . . . . . . .
Loads . . . . . . . . . . . . . . . . . . .
*LOAD CENTRIFUGAL . . . . . . .
*LOAD DAMPING . . . . . . . . .
*LOAD FORCE . . . . . . . . . . .
*LOAD GRAVITY . . . . . . . . . .
*LOAD PRESSURE . . . . . . . . .
*LOAD SHEAR . . . . . . . . . . .
*LOAD THERMAL BODY . . . . .
*LOAD THERMAL SURFACE . . .
*PRESTRESS BOLT . . . . . . . .
Contact and tied interfaces . . . . . . . .
*CONTACT . . . . . . . . . . . . .
*MERGE . . . . . . . . . . . . . . .
*MERGE FAILURE COHESIVE . . .
*MERGE FAILURE FORCE . . . . .
Rigid bodies . . . . . . . . . . . . . . . .
*RIGID BODY DAMPING . . . . .
*RIGID BODY INERTIA . . . . . .
*RIGID BODY JOINT . . . . . . .
*RIGID BODY MERGE . . . . . . .
Connectors . . . . . . . . . . . . . . . .
*CONNECTOR RIGID . . . . . . .
*CONNECTOR SPR . . . . . . . .
*CONNECTOR SPRING . . . . . .
Parameters and functions . . . . . . . .
*CURVE . . . . . . . . . . . . . . .
*FUNCTION . . . . . . . . . . . . .
*FUNCTION STATIC . . . . . . . .
*PARAMETER . . . . . . . . . . .
Geometries . . . . . . . . . . . . . . . .
*GEOMETRY BOX . . . . . . . . .
*GEOMETRY EFP . . . . . . . . .
*GEOMETRY PART . . . . . . . .
*GEOMETRY PIPE . . . . . . . . .
*GEOMETRY SEED COORDINATE
*GEOMETRY SEED NODE . . . .
*GEOMETRY SPHERE . . . . . . .
Sets . . . . . . . . . . . . . . . . . . . .
*SET ELEMENT . . . . . . . . . .
*SET FACE . . . . . . . . . . . . .
IMPETUS Afea Solver v.3.0
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*SET GEOMETRY . . . . . . . . . . . .
*SET NODE . . . . . . . . . . . . . . . .
*SET PART . . . . . . . . . . . . . . . .
Coordinate system . . . . . . . . . . . . . . .
*COORDINATE SYSTEM CYLINDRICAL
*COORDINATE SYSTEM FIXED . . . .
*COORDINATE SYSTEM NODE . . . .
Discrete Particles . . . . . . . . . . . . . . . .
*PBLAST . . . . . . . . . . . . . . . . .
*PSOIL . . . . . . . . . . . . . . . . . .
Smoothed Particle Hydrodynamics . . . . . . .
*SPH FLUID . . . . . . . . . . . . . . .
*SPH SENSOR PRESSURE . . . . . . .
*SPH WATER ENTRY LAB . . . . . . .
IMPETUS Afea Solver v.3.0
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4
Introduc on
About
IMPETUS Afea Solver is a general non-linear ﬁnite element software used to predict the large deformation behavior of materials. Such deformations usually occur in components and structures when they are subjected to
extreme loading conditions.
IMPETUS Afea has the vision to provide the best simulation aided engineering competence. Our software is
based on a selection of highly accurate and innovative algorithms. By utilizing new GPU hardware technology,
users are able to achieve extremely accurate results with low hardware investments and high computational speed.
Precision for decision is about being able to take the right decisions when evaluating your computational results, making IMPETUS Afea Solver a tool for decision making. The number of purely numerical parameters
that the user has to provide as input has been kept to a minimum, with a clear focus on simplicity combined
with accuracy and robustness. When the user deﬁnes the structural form, material properties and loading well,
the software delivers precise results.
The IMPETUS Afea Solver is not suited for all applications: some special cases requires a diﬀerent modelling
approach, however, for the problem classes of mechanical engineering for which the code has been developed,
our tool is ideal.
Further validation by comparing your numerical results with the corresponding experimental tests should always
be part of engineering philosophy when using non-linear ﬁnite element tools. Live tests to establish conﬁdence
in your model can never be excluded, but can be reduced when working with the IMPETUS Afea Solver, thus
saving you both time and money.
Users of the IMPETUS Afea Solver come from many diﬀerent markets: oil&gas, defence, aerospace, automotive amongst others. Despite the diﬀering applications, we identify key similarities in the modelling challenges
and develop new functionalities in the code. We continuously strive to innovate in order to improve the Solver,
relishing your challenges.
IMPETUS Afea Solver v.3.0
5
Disclaimer
So ware disclaimer
Software is provided ’as is’ without warranty of any kind, either express or implied, including, but not limited to,
the implied warranties of ﬁtness for a purpose, or the warranty of non-infringement. In no event shall IMPETUS
Afea AS be liable for any special, punitive, incidental, indirect or consequential damages of any kind, or any
damages whatsoever, including, without limitation, those resulting from loss of use, data or proﬁts, whether or
not IMPETUS Afea has been advised of the possibility of such damages, and on any theory of liability, arising
out of or in connection with the use of this software. No advice or information, whether oral or written, obtained
from IMPETUS Afea shall create any warranty for the software.
Limita on of liability
Under no circumstances shall IMPETUS Afea be liable for any losses or damages whatsoever, whether in contract,
tort or otherwise, from the use of, or reliance on, the Materials. NEITHER IMPETUS AFEA NOR ANY OF
ITS SUBSIDIARIES OR LICENSORS SHALL BE LIABLE FOR LOSS OF PROFITS, LOSS OR INACCURACY
OF DATA, OR INDIRECT, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES, EVEN IF ADVISED
OF THE POSSIBILITY OF SUCH DAMAGES. NOTHING IN THIS LIMITATION OF LIABILITY SHALL LIMIT
IMPETUS AFEA.S LIABILITY FOR DEATH OR PERSONAL INJURY CAUSED BY ITS NEGLIGENCE OR THE
NEGLIGENCE OF ITS EMPLOYEES. For the purposes of this section, ”IMPETUS Afea” shall include IMPETUS
Afea AS, and its divisions, subsidiaries, successors, parent companies, and their employees, partners, principals,
agents and representatives, and any third-party providers or sources of Materials.
IMPETUS Afea Solver v.3.0
6
Input
General informa on
Structure
A model is built up by a series of commands. Example models can be downloaded from the Samples menu in
our online manual.
*COMMAND
parameter1, parameter2, parameter3, ...
Abbrevia ons
For the input the following abbreviations can be used:
Abbreviation
E
ES
F
FS
G
GS
N
NS
P
PS
ALL
A
V
D
X
Y
Z
IMPETUS Afea Solver v.3.0
Description
element
element set
element face
element face set
geometry
geometry set
node
node set
part
part set
everything
acceleration
velocity
displacement
x-coordinate
y-coordinate
z-coordinate
7
Func ons & parameters
The following built in functions and parameters are supported by the commands FUNCTION and PARAMETER.
They can also be used when deﬁning expressions replacing numerical values in the input deck.
Function/parameter
pi
abs(x)
erf(x)
H(x)
sign(x)
min(x1, x2, ... xn)
max(x1, x2, ... xn)
sin(x)
cos(x)
exp(x)
sqrt(x)
smooth d(d max, t0, t1)
smooth v(d max, t0, t1)
smooth a(d max, t0, t1)
mine dry(m,x,y,z,z0)
ˆ
IMPETUS Afea Solver v.3.0
Description
3.141592653589793..
absolute value
classical error function
step function (H(x < 0) = 0; H(x ≥ 0) = 1)
sign function (sign(x < 0) = -1; sign(x ≥ 0) = 1)
min function
max function
trigonometric sine function
trigonometric cosine function
exponential function (exp(x) = ex )
square root
smooth displacement function going from 0 at time t0 to d max at t1
smooth velocity function that is obtained by diﬀerentiating smooth d with
respect to time
smooth acceleration function that is obtained by diﬀerentiating smooth v
with respect to time
pressure function that mimics a cylindical mine buried in dry soil (TNT
equivalent mass m, height/diameter ratio 1/3, charge center coordinate at
(x,y,z), ground level at z0
exponent (xˆy = xy )
8
The following functions are only supported by the command FUNCTION.
IMPETUS Afea Solver v.3.0
9
Function / parameter
crv(cid,x)
dist surf(xn,yn,zn)
dmg
dnorm
dt
epsp
fxc(cid)
fyc(cid)
fzc(cid)
fc(cid)
fxr(bcid)
fyr(bcid)
fzr(bcid)
fr(bcid)
pres
sigy0
t
volfs
vnorm
vtang
vx
vy
vz
vxn(nid)
vyn(nid)
vzn(nid)
vn(nid)
vxp(pid)
vyp(pid)
vzp(pid)
wip(pid)
wkp(pid)
x
y
z
X
Y
Z
xnorm
ynorm
znorm
xn(nid)
yn(nid)
zn(nid)
IMPETUS Afea Solver v.3.0
Description
returns the ordinata of curve cid at abscissa x
distance to material surface
damage
spring elongation
current time step size
eﬀective plastic strain
total contact force in x-direction in contact interface cid
total contact force in y-direction in contact interface cid
total contact force in z-direction in contact interface cid
total contact force in contact interface cid
reaction force in x-direction in *BC MOTION deﬁnition bcid
reaction force in y-direction in *BC MOTION deﬁnition bcid
reaction force in z-direction in *BC MOTION deﬁnition bcid
total reaction force in *BC MOTION deﬁnition bcid
contact pressure or hydrostatic pressure in material
initial yield stress (can be unique for each integration point if using INITIAL STATE WELDSIM)
current time
volume enclosed by face set fsid
local velocity in the normal direction to the surface of the structure
relative tangential sliding velocity (for use with CONTACT)
local velocity in x-direction (e.g.
velocity of an element face in
LOAD PRESSURE or a node in LOAD MOTION)
local velocity in y-direction
local velocity in z-direction
velocity in x-direction of node nid
velocity in y-direction of node nid
velocity in z-direction of node nid
velocity of node nid
velocity in x-direction of part pid
velocity in y-direction of part pid
velocity in z-direction of part pid
internal energy of part pid
kinetic energy of part pid
local x-coordinate (e.g. location of an element face in LOAD PRESSURE or
a node in LOAD MOTION)
local y-coordinate
local z-coordinate
initial x-coordinate (e.g. location of an element face in LOAD PRESSURE
or a node in LOAD MOTION)
initial y-coordinate
initial z-coordinate
x-component of local surface normal direction
y-component of local surface normal direction
z-component of local surface normal direction
x-coordinate of node nid
y-coordinate of node nid
z-coordinate of node nid
10
Binary and ASCII output
The solver outputs global simulation results in binary ﬁles with the extension .imp. A header ﬁle impetus.imp
is created when the simulation begins and each frame that is being output is written to its own ﬁle (impetus 0000.imp, impetus 0001.imp. etc.). The output interval is speciﬁed in the command OUTPUT. The global
output is complemented with a set of ASCII ﬁles having the extension .out. The data in the .imp and .out- ﬁles
can be read and visualized by the IMPETUS Afea Post Processor.
ASCII ﬁle
contact.out
dt.out
element.out
energy.out
merge.out
node.out
part.out
pblast.out
pblast contact.out
prescribed.out
rigid.out
sph contact.out
spr.out
spring.out
Content
Activated by command
Forces, energies and maximum penetration for each contact
interface
Time step size information
Stresses and plastic strain of a user deﬁned set of elements
Global energies
Forces between merged interfaces
Location, velocity and acceleration of a user deﬁned set of
nodes
Masses (physical and mass scaling) and energies by part
Discrete particle energy levels
Impulses transferred from discrete particles to FE parts
Reaction forces and moments on kinematically constrained
surfaces and rigid bodies
Displacements, velocities and forces acting on rigid bodies
SPH-structure contact forces, energies and largest penetration
SPR point connector forces, moments, deformations and
damage
Spring forces
CONTACT
IMPETUS Afea Solver v.3.0
Always active
OUTPUT ELEMENT
Always active
MERGE
OUTPUT NODE
PART
PBLAST
PBLAST
BC MOTION
MAT RIGID
SPH FLUID
CONNECTOR SPR
CONNECTOR SPRING
11
Input handling
Input handling
*END
*INCLUDE
*INCLUDE BINARY
*UNIT SYSTEM
IMPETUS Afea Solver v.3.0
12
Input handling
*END
*END
Descrip on
Deﬁnes the end of an input ﬁle.
IMPETUS Afea Solver v.3.0
13
Input handling
*INCLUDE
*INCLUDE
ﬁlename
sfx , sfy , sfz , nid oﬀset, eid oﬀset, pid oﬀset
x 0 , y0 , z 0 , x 1 , y1 , z 1
x
¯x , x
¯y , x
¯z , y¯x , y¯y , y¯z
Parameter deﬁni on
Variable
Description
ﬁlename
sfx , sfy , sfz
The path and the name of ﬁle to be included
Scale factors for nodal coordinates in x, y and z directions
default: 1
Number to add to all node ids
Number to add to all element ids
Number to add to all part ids
Start point for mesh translation
End point for mesh translation
New direction of x-axis
default: (1,0,0)
New direction of y-axis
default: (0,1,0)
nid oﬀset
eid oﬀset
pid oﬀset
x0 , y0 , z0
x1 , y1 , z1
x
¯x , x
¯y , x
¯z
y¯x , y¯y , y¯z
Descrip on
This command is used to merge a ﬁle with the input. The data in the included ﬁle can be transformed (optional).
A point in the original conﬁguration x will be moved to location x0 according to:
 


x
¯x y¯x z¯x
sfx
 (x − x0 )
¯y y¯y z¯y  · 
sfy
x0 = x1 +  x
x
¯z y¯z z¯z
sfz
Hence, a point x0 in the original conﬁguration will be moved to x1 . This is the base point for both scaling
operations and rotations.
IMPETUS Afea Solver v.3.0
14
Input handling
*INCLUDE BINARY
*INCLUDE BINARY
ﬁlename
Parameter deﬁni on
Variable
Description
ﬁlename
The path and the name of binary ﬁle to be included
Descrip on
This command is used to merge a binary ﬁle with the input.
IMPETUS Afea Solver v.3.0
15
Input handling
*UNIT SYSTEM
*UNIT SYSTEM
units
Parameter deﬁni on
Variable
Description
units
Unit system
options:
SI → [m, kg, s]
MMTONS → [mm, ton, s]
CMGUS → [cm, g, µs]
IPS → [in, slinch, s]
MMKGMS → [mm, kg, ms]
Descrip on
Command to inform the solver of used unit system. A unit system must be speciﬁed if the PBLAST command is
used. Specifying a unit system also facilitates the scanning for suspected errors in the input deck. Possible errors
or mistakes are reported in the ASCII ﬁle ”impetus.attention”.
IMPETUS Afea Solver v.3.0
16
Solu on control and techniques
Solu on control and techniques
*ANALYSIS BUCKLING EIGENMODE
*ANALYSIS DYNAMIC EIGENMODE
*ANALYSIS LINEAR STATIC
*GPU
*SMS
*SMS CLUSTER
*TIME
IMPETUS Afea Solver v.3.0
17
Solu on control and techniques
*ANALYSIS BUCKLING EIGENMODE
*ANALYSIS BUCKLING EIGENMODE
N, psid
σstif f
Parameter deﬁni on
Variable
Description
N
psid
Number of computed eigenmodes
ID of part set that is included in the linear solution
default: complete model is active
Stress stiﬀening activation ﬂag
options:
0 → buckling due to external loads (default)
1 → buckling due to scaling of initial stress ﬁeld
σstif f
Descrip on
This command is used to activate and to deﬁne settings for a dynamic eigenmode analysis.
IMPETUS Afea Solver v.3.0
18
Solu on control and techniques
*ANALYSIS DYNAMIC EIGENMODE
*ANALYSIS DYNAMIC EIGENMODE
N, psid
σstif f
Parameter deﬁni on
Variable
Description
N
psid
Number of computed eigenmodes
ID of part set that is included in the eigenmode analysis
default: complete model is active
Stress stiﬀening activation ﬂag
options:
0 → not active
1 → active from applied external loads
2 → active from initial stresses
σstif f
Descrip on
This command is used to activate and to deﬁne settings for a dynamic eigenmode analysis.
IMPETUS Afea Solver v.3.0
19
Solu on control and techniques
*ANALYSIS LINEAR STATIC
*ANALYSIS LINEAR STATIC
solver, psid, when
typesub , Nsub , σstif f
Parameter deﬁni on
Variable
Description
solver
Solution technique
options:
0 → direct
1 → iterative (conjugate gradient)
ID of a part set listing parts that are included in the linear solution
default: complete model is active
Flag indicating when to carry out the linear static analysis
options:
0 → at time = 0
1 → at termination time
Sub-structuring method
options:
0 → no sub-structuring
1 → based on free bodies
2 → direction based
Number of sub-structures (only used if typesub =2)
Stress stiﬀening activation ﬂag
options:
0 → not active
1 → active
psid
when
typesub
Nsub
σstif f
Descrip on
This command is used to specify how and when to carry out a linear static analysis.
The linear static analysis can either be carried out at time 0 (when=0) or at termination time (when=1).
If when=0 the explicit dynamic solver will proceed (until termination time) from the state predicted by the linear
static solver. Note that if the termination time (see TIME) is set to 0 only a linear static analysis will be carried
out. If when=1 the linear static solver is invoked once the explicit dynamic solver has reached termination time.
IMPETUS Afea Solver v.3.0
20
Solu on control and techniques
*GPU
*GPU
sms, elem, blast
Parameter deﬁni on
Variable
Description
sms
Flag for selective mass scaling and time integration
options:
0 → CPU
1 → GPU
Flag for element processing
options:
0 → CPU
1 → GPU
Flag for particle blast calculations
options:
0 → CPU
1 → GPU
elem
blast
Descrip on
Activate GPU functionality. Requires a CUDA enabled graphics card with compute capability 1.3 or higher.
IMPETUS Afea Solver v.3.0
21
Solu on control and techniques
*SMS
*SMS
entype, enid, sf
Parameter deﬁni on
Variable
Description
entype
Entity type
options: P, PS
Entity identiﬁcation number
Mass scaling factor
enid
sf
Descrip on
Selective mass scaling functionality, as decribed by Olovsson et al. (2005). The critical time step of an element is:
∆tc =
√
1 + sf · ∆tc0
where ∆tc0 is the critical time step without mass scaling.
IMPETUS Afea Solver v.3.0
22
Solu on control and techniques
*SMS CLUSTER
*SMS CLUSTER
entype, enid, sf , dmax
Parameter deﬁni on
Variable
Description
entype
Entity type
options: P, PS
Entity identiﬁcation number
Mass scaling factor
Maximum node distance
enid
sf
dmax
Descrip on
Selective mass scaling functionality, especially designed for the treatment of small clusters of nodes. The method
is similar to SMS. A node belongs to a cluster if it is not further away than dmax from at least one other member
of the cluster.
IMPETUS Afea Solver v.3.0
23
Solu on control and techniques
*TIME
*TIME
tterm , sf∆t , ∆tmin , ∆tmax , msmax
Parameter deﬁni on
Variable
Description
tterm
sf∆t
Termination time
Time step scale factor. It should range between 0 and 1
default: 0.9
Time step size, below which mass scaling will be activated
default: 0
Maximum allowed time step size
default: 1.0e10
Maximum allowed mass scaling factor on element level
default: 1.0e10
∆tmin
∆tmax
msmax
Descrip on
This command is used to deﬁne the duration of the simulated event and to specify parameters controlling the
time step size.
Note that artiﬁcial mass is added if needed in order to prevent the critical time step from dropping below
∆tmin . msmax limits maximum allowed mass scaling factor.
IMPETUS Afea Solver v.3.0
24
Output
Output
*OUTPUT
*OUTPUT
*OUTPUT
*OUTPUT
*OUTPUT
ELEMENT
FORMING
NODE
SENSOR
IMPETUS Afea Solver v.3.0
25
Output
*OUTPUT
*OUTPUT
∆timp , ∆tascii , ∆tdb
nﬁlter, eﬁlter, entyperes , enidres
Parameter deﬁni on
Variable
Description
∆timp
Output interval for complete model (.imp-ﬁles)
default: ∆timp = tterm /100
Output interval for ASCII data (see list of .out-ﬁles in General section)
default: ∆tascii = tterm /1000
Output interval for model database and state ﬁles. No database or state ﬁles will be
output if ∆tdb is larger than tterm (see TIME)
default: a database ﬁle is generated at tterm
Filter for node data that will be written to impetus.imp
options:
0 → output all node data
1 → output displacements only
Filter for element data that will be written to impetus.imp
options:
0 → output all element data
1 → output eﬀective stress, plastic strain and damage
2 → output no element data
Entity type for state ﬁle output. The state ﬁle is an ASCII ﬁle in command format containing elements, nodes (coordinates and velocities) and contact information. Stresses,
strains and state variables are output to a separate binary ﬁle.
options: P, PS, ALL
default: no state ﬁle
Entity ID for state ﬁle output
∆tascii
∆tdb
nﬁlter
eﬁlter
entyperes
enidres
Descrip on
This command contains output parameters, such as output frequency and ﬁlter. The ﬁlter is used to reduce the
size of the .imp-ﬁles.
If deﬁning entyperes and enidres , elements, node coordinates and velocities and the current contact state will be
written to the ASCII ﬁle impetus state1.k. All state variables, stresses and strains are written to a binary ﬁle
impetus state1.bin. impetus state1.k and impetus state1.bin can be read by IMPETUS Afea Solver. Note that
impetus state1.bin is included in a model using the command INCLUDE BINARY.
IMPETUS Afea Solver v.3.0
26
Output
*OUTPUT ELEMENT
*OUTPUT ELEMENT
entype, enid
Parameter deﬁni on
Variable
Description
entype
Entity type
options: E, ES
Entity identiﬁcation number
enid
Descrip on
Outputs element results to the ASCII ﬁle element.out.
IMPETUS Afea Solver v.3.0
27
Output
*OUTPUT FORMING
*OUTPUT FORMING
form
Parameter deﬁni on
Variable
Description
form
Flag to activate output of sheet thickness
options:
0 → do not output sheet thickness
1 → output sheet thickness
Descrip on
Activates calculation and output of sheet thickness to the .imp-database.
IMPETUS Afea Solver v.3.0
28
Output
*OUTPUT NODE
*OUTPUT NODE
entype, enid
Parameter deﬁni on
Variable
Description
entype
Entity type
options: N,NS
Entity identiﬁcation number
enid
Descrip on
Outputs nodal results to the ASCII ﬁle node.out
IMPETUS Afea Solver v.3.0
29
Output
*OUTPUT SENSOR
*OUTPUT SENSOR
coid, pid, x0 , y0 , z0 , R, csysid
Parameter deﬁni on
Variable
Description
coid
pid
Sensor ID
ID of part where the sensor is located
options: Part ID or DP for discrete particles
Initial x-coordinate of sensor
Initial y-coordinate of sensor
Initial z-coordinate of sensor
Sensor radius (for pid=DP only)
Optional local coordinate system ID
x0
y0
z0
R
csysid
Descrip on
A sensor can either sample the local state at a material point inside a speciﬁed part, or sample the discrete
particle state at a speciﬁed ﬁxed point in space (see PBLAST[/ref] or [ref]PSOIL).
If referring to a part ID, the command will sample the local state at a material point initially located at coordinate
(x0 , y0 , z0 ). The solver uses the nearest integration point and node (in the speciﬁed part) and outputs the sampled
data to the ASCII ﬁle sensor.out.
If specifying pid=DP (discrete particles) the sensor is ﬁxed in space and will sample the average particle density,
velocity and pressure inside a sphere with radius R. The data is then output to the ASCII ﬁle pblast sensor.out.
Stresses, coordinates, displacements and velocities are output in the local coordinate system (if deﬁned). It is to
be noted that displacements are computed relatively the origin of the local system.
IMPETUS Afea Solver v.3.0
30
Mesh Commands
Mesh Commands
*ACTIVATE ELEMENTS
*COMPONENT BOLT
*COMPONENT BOX
*COMPONENT CYLINDER
*COMPONENT PIPE
*COMPONENT REBAR
*COMPONENT SPHERE
*MERGE DUPLICATED NODES
*REFINE
*SMOOTH MESH
*TRANSFORM MESH CARTESIAN
*TRANSFORM MESH CYLINDRICAL
*TRIM
*WELD
IMPETUS Afea Solver v.3.0
31
Mesh Commands
*ACTIVATE ELEMENTS
*ACTIVATE ELEMENTS
coid, entype, enid, tbirth , tdeath , ξ
Parameter deﬁni on
Variable
Description
coid
entype
Command ID
Entity type
options: P, PS
Entity ID
Time or FUNCTION deﬁning element activation
Time or FUNCTION deﬁning element deactivation
Optional strength of not yet activated elements
default: 0
enid
tbirth
tdeath
ξ
Descrip on
This command lets the user activate or deactivate elements at a pre-deﬁned time or on a certain signal. If a
FUNCTION is used an element is activated or deactivated on function values > 0.
The optional constant 0 ≤ ξ ≤ 1 is used to scale the internal forces of unactivated elements. ξ is typically used
in situations where nodes of unactivated elements are part of a MERGE interface and where the nodes need to be
active from time 0 to avoid the formation of gaps. A typical application is weld seams where the weld elements
need to follow the deformation of the base material. Else they will not be activated at the correct location.
IMPETUS Afea Solver v.3.0
32
Mesh Commands
*COMPONENT BOLT
*COMPONENT BOLT
coid, pid1 , pid2 , pid3 , pid4 , csysid
D, L, h, t
Parameter deﬁni on
Variable
Description
coid
pid1
Component ID
Bolt part ID
default: no bolt
Nut part ID
default: no nut
Washer 1 part ID
default: no washer
Washer 2 part ID
default: no washer
Local coordinate system ID
default: global coordinates are used
Bolt diameter
Bolt length
Axial distance between washers
Washer thickness
pid2
pid3
pid4
csysid
D
L
h
t
Descrip on
This command is used to deﬁne and position a bolt.
IMPETUS Afea Solver v.3.0
33
Mesh Commands
*COMPONENT BOX
*COMPONENT BOX
coid, pid, Nx , Ny , Nz , csysid
x 1 , y1 , z 1 , x 2 , y2 , z 2
Parameter deﬁni on
Variable
Description
coid
pid
Nx
Ny
Nz
csysid
Component ID
Part ID
Number of elements in local x-direction
Number of elements in local y-direction
Number of elements in local z-direction
Local coordinate system ID
default: global coordinates are used
Box corner coordinate 1
Box corner coordinate 2
x1 , y1 , z1
x2 , y2 , z2
Descrip on
This command is used to deﬁne a box with part ID pid.
IMPETUS Afea Solver v.3.0
34
Mesh Commands
*COMPONENT CYLINDER
*COMPONENT CYLINDER
coid, pid, N1 , N2 , csysid
x1 , y1 , z1 , x2 , y2 , z2 , R1 , R2
Parameter deﬁni on
Variable
Description
coid
pid
N1
N2
csysid
Component ID
Part ID
Number of elements in axial direction
Mesh density parameter
Local coordinate system ID
default: global coordinates are used
Face center coordinate 1
Face center coordinate 2
Radius at face 1
Radius at face 2
default: R2 = R1
x1 , y1 , z1
x2 , y2 , z2
R1
R2
Descrip on
This command is used to deﬁne a solid cylinder with part ID pid.
IMPETUS Afea Solver v.3.0
35
Mesh Commands
*COMPONENT PIPE
*COMPONENT PIPE
coid, pid, N1 , N2 , N3 , csysid, αc
x1 , y1 , z1 , x2 , y2 , z2 , R1 , R2
R3 , R4
Parameter deﬁni on
Variable
Description
coid
pid
N1
N2
N3
csysid
Component ID
Part ID
Number of elements in axial direction
Number of elements in circumferetial direction
Number of elements in thickness direction
Local coordinate system ID
default: global coordinates are used
Angle in circumferential direction
default: 360◦ (full pipe)
Face center coordinate 1
Face center coordinate 2
First radius at x1
Second radius at x1
First radius at x2
default: R3 =R1
Second radius at x2
default: R4 =R2
αc
x1 , y1 , z1
x2 , y2 , z2
R1
R2
R3
R4
Descrip on
This command is used to deﬁne a pipe with part ID pid. Note that the smaller of R1 , R2 (and R3 , R4 ) is
automatically taken as the inner radius.
IMPETUS Afea Solver v.3.0
36
Mesh Commands
*COMPONENT SPHERE
*COMPONENT SPHERE
coid, pid, N, Nc , csysid, αc
x0 , y0 , z0 , R1 , R2
Parameter deﬁni on
Variable
Description
coid
pid
N
Nc
csysid
Component ID
Part ID
Mesh density parameter (see ﬁgure below)
Number of elements in circumferential direction (only used if αc 6= 360◦ )
Local coordinate system ID
default: global coordinates are used
Angle in circumferential direction
default: 360◦ (full sphere)
Sphere center coordinate
Sphere radius 1
Sphere radius 2
αc
x0 , y0 , z0
R1
R2
Descrip on
This command is used to deﬁne a sphere with part ID pid. A hollow sphere is generated if both R1 and R2 are
non-zero.
IMPETUS Afea Solver v.3.0
37
Mesh Commands
*MERGE DUPLICATED NODES
*MERGE DUPLICATED NODES
entypes , enids , entypem , enidm , tol
Parameter deﬁni on
Variable
Description
entypes
Slave entity type
options: P, PS
Slave entity identiﬁcation number
Master entity type
options: P, PS
Master entity identiﬁcation number
Tolerance for merging nodes
default: 0
enids
entypem
enidm
tol
Descrip on
This command is used to merge duplicated nodes.
IMPETUS Afea Solver v.3.0
38
Mesh Commands
*REFINE
*REFINE
entype, enid, level, gid, no thick, dmin , αmax
Parameter deﬁni on
Variable
Description
entype
Entity type
options: P, PS
Entity identiﬁcation number
Level of reﬁnement
ID of a GEOMETRY that deﬁnes a sub-space for reﬁnement
default: all elements in the selected part/part set will be reﬁned
Disables reﬁnement in through thickness direction
options:
0 → reﬁnement in plate thickness direction is allowed
1 → reﬁnement in plate thickness direction is turned oﬀ
Minimum element dimension for reﬁnement
default: all elements are reﬁned
External element face smoothing angle
default: no surface smoothing
enid
level
gid
no thick
dmin
αmax
Descrip on
This command is used to reﬁne the grid in a selected region of a part or part set. Pentahedra and tetrahedra
elements can currently only handle reﬁnement level = 2. The surface of the reﬁned region is smoothed if the
angle between two adjacent element faces is smaller than or equal to αmax .
IMPETUS Afea Solver v.3.0
39
Mesh Commands
*SMOOTH MESH
*SMOOTH MESH
entype, enid, αmax , internal
Parameter deﬁni on
Variable
Description
entype
Entity type
options: N, NS, P, PS, G, ALL
Entity identiﬁcation number
External element face smoothing angle
Flag to activate smoothing of internal material interfaces and to propagate smoothing
to internal nodes
options:
0 → only smoothing of external material surface
1 → internal smnoothing activated
enid
αmax
internal
Descrip on
This command is used to smooth the surface of quadratic and cubic element surfaces. The surface is smoothed if
the angle between two adjacent element faces is smaller than or equal to αmax . By default, only external element
faces are smoothed. The internal ﬂag turns on smoothing of internal material interfaces and also propagates the
surface smoothing to the interior of the mesh.
IMPETUS Afea Solver v.3.0
40
Mesh Commands
*TRANSFORM MESH CARTESIAN
*TRANSFORM MESH CARTESIAN
coid, entype, enid, csysid, ﬁd1 , ﬁd2 , ﬁd3
Parameter deﬁni on
Variable
Description
coid
entype
Command ID
Entity type
options: G, GS, P, PS
Entity ID
Local coordinate system ID
default: global coordinates are used
FUNCTION deﬁning the displacement in local x-direction
FUNCTION deﬁning the displacement in local y-direction
FUNCTION deﬁning the displacement in local z-direction
enid
csysid
ﬁd1
ﬁd2
ﬁd3
Descrip on
This command is used to transform a mesh. The transformation is expressed as diplacements in global or local
cartesian coordinates. A local system is used if csysid is deﬁned.
IMPETUS Afea Solver v.3.0
41
Mesh Commands
*TRANSFORM MESH CYLINDRICAL
*TRANSFORM MESH CYLINDRICAL
coid, entype, enid, csysid, ﬁd1 , ﬁd2 , ﬁd3 , ﬁd4
Parameter deﬁni on
Variable
Description
coid
entype
Command ID
Entity type
options: G, GS, P, PS
Entity ID
ID of cylindrical coordinate system
FUNCTION deﬁning radial displacement of inner surface
FUNCTION deﬁning radial displacement of outer surface
FUNCTION deﬁning axial displacement
FUNCTION deﬁning tangential displacement
enid
csysid
ﬁd1
ﬁd2
ﬁd3
ﬁd4
Descrip on
This command is used to transform a mesh. The transformation is expressed as diplacements in cylindrical
coordinates (R, z, θ). R is the radius, z is the axial coordinate and θ is a circumferential angle ranging from 0◦
to 360◦ .
If ﬁd1 6= ﬁd2 inner and outer surfaces use diﬀerent radial transformations (see example below). In such situations
only nodes on the surface of the body are transformed. Interior nodes are not treated. However, all nodes are
transformed in the radial direction if ﬁd1 = ﬁd2 .
Figure 1: Interior and exterior surfaces
IMPETUS Afea Solver v.3.0
42
Mesh Commands
*TRIM
*TRIM
entype, enid, nidseed , ttrim , x
ˆ, yˆ, zˆ
x 1 , y1 , z 1
.
x n , yn , z n
Parameter deﬁni on
Variable
Description
entype
Entity type
options: P, PS
Entity ID
Seed node id, marking material to keep after trimming
Trim time
X-component of trimline projection direction
Y-component of trimline projection direction
Z-component of trimline projection direction
X-coordinate of trim line point 1
Y-coordinate of trim line point 1
Z-coordinate of trim line point 1
X-coordinate of trim line point n
Y-coordinate of trim line point n
Z-coordinate of trim line point n
enid
nidseed
ttrim
x
ˆ
yˆ
zˆ
x1
y1
z1
xn
yn
zn
Descrip on
Trimming function for metal stamping applications. The trim path is a discretized line, deﬁned by a list of
coordinates.
IMPETUS Afea Solver v.3.0
43
Mesh Commands
*WELD
*WELD
nsid, stype, pid, nseg, a, rof f
Parameter deﬁni on
Variable
Description
nsid
stype
ID of node set deﬁning weld path
Weld cross section discretization
options:
1 → 1 triangle
2 → 3 quads
3 → 1 quad
Part ID of generated weld mesh
Number of elements along weld path
default: Same discretization as the weld path
Weld thickness (a-value)
Weld root oﬀset
pid
nseg
a
rof f
Descrip on
This command is used to generate the mesh of a weld seam. The solver terminates immediately after outputting
the generated grid to the ﬁle weld.k. The weld seam is to be connected to the welded parts with the MERGE
command. The mechanical properties in the heat aﬀected zone (HAZ) can be accounted for by importing results
from WeldSim (TM) through the command INITIAL STATE WELDSIM[/ref], or by manually deﬁng properties
through [ref]INITIAL STATE HAZ.
Note that a weld root oﬀset (rof f > 0) requires a 1-quad section (stype = 3). The 1-quad section is not
allowed if rof f = 0.
IMPETUS Afea Solver v.3.0
44
Nodes and connec vity
Nodes and connec vity
*CHANGE P-ORDER
*ELEMENT CHEX
*ELEMENT CPRISM
*ELEMENT CTET
*ELEMENT QHEX
*ELEMENT QPRISM
*ELEMENT QTET
*ELEMENT REBAR
*ELEMENT SHELL
*ELEMENT SOLID
*NODE
*PART
IMPETUS Afea Solver v.3.0
45
Nodes and connec vity
*CHANGE P-ORDER
*CHANGE P-ORDER
entype, enid, order, gid
Parameter deﬁni on
Variable
Description
entype
Entity type
options: P, PS, ALL
Entity identiﬁcation number
New element polynomial order
options: 1, 2, 3
ID of a GEOMETRY that deﬁnes a sub-space for change of polynomial order
default: No geometry. This means that all elements in the selected part/part set will
change polynomial order
enid
order
gid
Descrip on
Change element polynomial order in a selected region of a part or part set.
IMPETUS Afea Solver v.3.0
46
Nodes and connec vity
*ELEMENT CHEX
*ELEMENT CHEX
eid, pid
nid01 , ... , nid10
nid11 , ... , nid20
nid21 , ... , nid30
nid31 , ... , nid40
nid41 , ... , nid50
nid51 , ... , nid60
nid61 , ... , nid64
Parameter deﬁni on
Variable
Description
eid
pid
nid01 ,
nid11 ,
nid21 ,
nid31 ,
nid41 ,
nid51 ,
nid61 ,
Unique element identiﬁcation number
Part identiﬁcation number
Element nodes 01 - 10
Element nodes 11 - 20
Element nodes 21 - 30
Element nodes 31 - 40
Element nodes 41 - 50
Element nodes 51 - 60
Element nodes 61 - 64
...
...
...
...
...
...
...
,
,
,
,
,
,
,
nid10
nid20
nid30
nid40
nid50
nid60
nid64
Descrip on
Cubic hexahedron element deﬁnition.
Figure 2: Cubic hexahedron 1 - Corner and edge nodes
IMPETUS Afea Solver v.3.0
47
Nodes and connec vity
Figure 3: Cubic hexahedron 2 - Face nodes
Figure 4: Cubic hexahedron 3 - Internal nodes
IMPETUS Afea Solver v.3.0
48
Nodes and connec vity
*ELEMENT CPRISM
*ELEMENT CPRISM
eid, pid
nid01 , ... , nid10
nid11 , ... , nid20
nid21 , ... , nid30
nid31 , ... , nid40
Parameter deﬁni on
Variable
Description
eid
pid
nid01 ,
nid11 ,
nid21 ,
nid31 ,
Unique element identiﬁcation number
Part identiﬁcation number
Element nodes 01 - 10
Element nodes 11 - 20
Element nodes 21 - 30
Element nodes 31 - 40
...
...
...
...
,
,
,
,
nid10
nid20
nid30
nid40
Descrip on
Cubic pentahedron (wedge, cake) element deﬁnition.
Figure 5: Cubic pentahedron 1 - Corner and edge nodes
IMPETUS Afea Solver v.3.0
49
Nodes and connec vity
Figure 6: Cubic pentahedron 2 - Face nodes
Figure 7: Cubic pentahedron 3 - Internal nodes
IMPETUS Afea Solver v.3.0
50
Nodes and connec vity
*ELEMENT CTET
*ELEMENT CTET
eid, pid
nid01 , ... , nid10
nid11 , ... , nid20
Parameter deﬁni on
Variable
Description
eid
pid
nid01 , ... , nid10
nid11 , ... , nid20
Unique element identiﬁcation number
Part identiﬁcation number
Element nodes 01 - 10
Element nodes 11 - 20
Descrip on
Cubic tetrahedron element deﬁnition.
Figure 8: Cubic tetrahedron 1 - Corner and edge nodes
IMPETUS Afea Solver v.3.0
51
Nodes and connec vity
Figure 9: Cubic tetrahedron 2 - Face nodes
IMPETUS Afea Solver v.3.0
52
Nodes and connec vity
*ELEMENT QHEX
*ELEMENT QHEX
eid, pid
nid01 , ... , nid10
nid11 , ... , nid20
nid21 , ... , nid27
Parameter deﬁni on
Variable
Description
eid
pid
nid01 , ... , nid10
nid11 , ... , nid20
nid21 , ... , nid27
Unique element identiﬁcation number
Part identiﬁcation number
Element nodes 01 - 10
Element nodes 11 - 20
Element nodes 21 - 27
Descrip on
Quadratic hexahedron element deﬁnition.
Figure 10: Quadratic hexahedron 1 - Corner and edge nodes
IMPETUS Afea Solver v.3.0
53
Nodes and connec vity
Figure 11: Quadratic hexahedron 2 - Face nodes
IMPETUS Afea Solver v.3.0
54
Nodes and connec vity
*ELEMENT QPRISM
*ELEMENT QPRISM
eid, pid, nid01 , ... , nid08
nid09 , ... , nid18
Parameter deﬁni on
Variable
Description
eid
pid
nid01 , ... , nid08
nid09 , ... , nid18
Unique element identiﬁcation number
Part identiﬁcation number
Element nodes 01 - 08
Element nodes 09 - 18
Descrip on
Quadratic pentahedron (wedge, cake) element deﬁnition.
Figure 12: Quadratic pentahedron 1 - Corner and edge nodes
IMPETUS Afea Solver v.3.0
55
Nodes and connec vity
Figure 13: Quadratic pentahedron 2 - Face nodes
IMPETUS Afea Solver v.3.0
56
Nodes and connec vity
*ELEMENT QTET
*ELEMENT QTET
eid, pid
nid1 , ... , nid10
Parameter deﬁni on
Variable
Description
eid
pid
nid1 , ... , nid10
Unique element identiﬁcation number
Part identiﬁcation number
Element nodes 1 - 10
Descrip on
Quadratic tetrahedron element deﬁnition.
Figure 14: Quadratic tetrahedron - a solid element with 10 nodes
IMPETUS Afea Solver v.3.0
57
Nodes and connec vity
*ELEMENT SHELL
*ELEMENT SHELL
eid, pid, nid1 , nid2 , nid3 , nid4
Parameter deﬁni on
Variable
Description
eid
pid
nid1
nid2
nid3
nid4
Unique element identiﬁcation number
Part identiﬁcation number
Element node 1
Element node 2
Element node 3
Element node 4
Descrip on
Linear triangular or quadrilateral shell element deﬁnition. Currently only for use with MAT RIGID.
IMPETUS Afea Solver v.3.0
58
Nodes and connec vity
*ELEMENT SOLID
*ELEMENT SOLID
eid, pid, nid1 , nid2 , nid3 , nid4 , nid5 , nid6 , nid7 , nid8
Parameter deﬁni on
Variable
Description
eid
pid
nid1
nid2
nid3
nid4
nid5
nid6
nid7
nid8
Unique element identiﬁcation number
Part identiﬁcation number
Element node 1
Element node 2
Element node 3
Element node 4
Element node 5
Element node 6
Element node 7
Element node 8
Descrip on
Deﬁnes a solid element.
linear tetrahedron = 4 nodes:
eid, pid, nid1 , nid2 , nid3 , nid4 , nid4 , nid4 , nid4 , nid4
Figure 15: Linear tetrahedron - Solid element with four nodes
linear hexahedron = 8 nodes:
eid, pid, nid1 , nid2 , nid3 , nid4 , nid5 , nid6 , nid7 , nid8
linear pentahedron = 6 nodes:
eid, pid, nid1 , nid2 , nid3 , nid4 , nid5 , nid5 , nid6 , nid6
IMPETUS Afea Solver v.3.0
59
Nodes and connec vity
Figure 16: Linear hexahedron - Solid element with eight nodes
Figure 17: Linear pentahedron - Solid element with six nodes
IMPETUS Afea Solver v.3.0
60
Nodes and connec vity
*NODE
*NODE
nid, x, y, z, bc
Parameter deﬁni on
Variable
Description
nid
x, y, z
bc
Unique node identiﬁcation number
Node coordinate
Translational constraint
options: 0, X, Y, Z, XY, YZ, ZX, XYZ
Descrip on
Deﬁnes a node.
IMPETUS Afea Solver v.3.0
61
Nodes and connec vity
*PART
*PART
erode
pid, mid, eosid, h, αmax , ∆terode , erode
geo , v
Parameter deﬁni on
Variable
Description
pid
mid
eosid
Unique part identiﬁcation number or range of parts
Material identiﬁcation number
Equation-of-state identiﬁcation number
default: equation-of-state is not used
Shell thickness (only used for mass calculation, not in contact) or rebar diameter
default: 1
External element face smoothing angle
default: no surface smoothing, i.e. ang smooth = 0◦
Time step size below which elements are eroded
default: 0
Eﬀective deviatoric geometric strain above which elements are eroded
default: 1.0e20
Volumetric strain above which elements are eroded
default: 1.0e20
h
αmax
∆terode
erode
geo
erode
v
Descrip on
The command is used to assign properties to a part or to a range of parts. Surface smoothing is applied if the
angle between the normal vectors of two adjacent higher order external faces is smaller than αmax . Part commands
can be assigned a title. The title shows up in part.out and in the part list in IMPETUS Afea Visualizer.
An element is eroded if its critical time step drops below ∆terode , if the eﬀective deviatoric geometrical strain geo
erode . The eﬀective deviatoric
reaches erode
geo in at least one integration point, or if the volumetric strain exceeds v
geometric strain is deﬁned as:
√
2
dev : dev
geo =
3
where dev is the deviatoric strain tensor. Note that elements can also be eroded at material failure if setting the
erosion ﬂag to 1 in the damage property command.
IMPETUS Afea Solver v.3.0
62
Material proper es
Material proper es
*EOS GRUNEISEN
*EOS POLYNOMIAL
*EOS TAIT
*MAT CERAMIC
*MAT CONCRETE
*MAT CREEP
*MAT ELASTIC
*MAT FLUID
*MAT FOAM
*MAT FORMING
*MAT FORMING R
*MAT GRANULAR CAP
*MAT HJC CONCRETE
*MAT JC
*MAT JC FIELD
*MAT JH CERAMIC
*MAT LIBRARY
*MAT METAL
*MAT MOONEY RIVLIN
*MAT MULTILAYER ORTHOTROPIC
*MAT ORTHOTROPIC
*MAT PWL
*MAT REBAR
*MAT RIGID
*MAT USER JS
*MAT USER X
*MAT VISCO PLASTIC
IMPETUS Afea Solver v.3.0
63
Material proper es
*PROP
*PROP
*PROP
*PROP
*PROP
*PROP
*PROP
*PROP
DAMAGE BRITTLE
DAMAGE CL
DAMAGE CL ANISOTROPIC
DAMAGE IMP
DAMAGE IMP ISO
DAMAGE JC
DAMAGE STRAIN
THERMAL
IMPETUS Afea Solver v.3.0
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Material proper es
*EOS GRUNEISEN
*EOS GRUNEISEN
eosid, S, Γ
Parameter deﬁni on
Variable
Description
eosid
S
Γ
Unique EOS identiﬁcation number
Linear Hugoniot slope coeﬃcient
Gruneisen gamma
Descrip on
This is the Mie-Gruneisen equation-of-state. Note that the linear bulk modulus, K, is determined from the elastic
properties in the material command.
)
(
Kη
Γη
p=
+ Γρ0 e
· 1−
(1 − Sη)2
2
where ρ is the current density, ρ0 is the initial density and e is the speciﬁc internal energy. η is a measure
of the volumetric compression.
η =1−
IMPETUS Afea Solver v.3.0
ρ0
ρ
65
Material proper es
*EOS POLYNOMIAL
*EOS POLYNOMIAL
eosid, A, B, C
Parameter deﬁni on
Variable
Description
eosid
A
B
C
Unique EOS identiﬁcation number
Polynomial coeﬃcient
Polynomial coeﬃcient
Polynomial coeﬃcient
Descrip on
This is a polynomial equation-of-state that currently only works with SPH particles. Note that the linear bulk
modulus, K, is determined from the elastic properties in the material command.
p = Kµ + Aµ2 +
B + Cµ
e
1+µ
where e is the speciﬁc internal energy per unit volume and µ is a measure of the volumetric compression.
µ=
IMPETUS Afea Solver v.3.0
ρ
−1
ρ0
66
Material proper es
*EOS TAIT
*EOS TAIT
eosid, γ
Parameter deﬁni on
Variable
Description
eosid
γ
Unique EOS identiﬁcation number
Exponent in pressure-density relationship
Descrip on
This equation-of-state currently only works with SPH particles. Note that the linear bulk modulus, K, is determined from the elastic properties in the material command.
)
(( )γ
ρ
−1
p=K
ρ0
IMPETUS Afea Solver v.3.0
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Material proper es
*MAT CERAMIC
*MAT CERAMIC
mid, ρ, G
A0 , B0 , Af , Bf , f , Kc , ts , αs
K1 , K2 , K3 , β
Parameter deﬁni on
Variable
Description
mid
ρ
G
A0
B0
Af
Bf
f
Kc
ts
αs
K1
K2
K3
β
Unique material identiﬁcation number
Density
Shear modulus
Yield surface parameter
Yield surface parameter
Failure surface parameter
Failure surface parameter
Volumetric crushing strain
Fracture toughness
Time to develop spall fracture at threshold stress
Exponent controlling time to develop spall fracture
Linear bulk stiﬀness term
Quadratic bulk stiﬀness term
Cubic bulk stiﬀness term
Parameter controlling the plastic ﬂow direction at crushing. β must be larger than 0 and
can not exceed 1.
default: 1 → associated plastic ﬂow
Descrip on
This is a ceramic model with diﬀerent failure mechanisms in compression and tension. The material is assumed
to have a pressure dependent shear resistance. At positive pressures, plastic ﬂow is a combination of shearing
and dilatation. Inelastic dilatation is interpreted as crushing that gradually reduces the shear resistance of the
material. A brittle fracture criterion combined with node splitting is used on the tensile side.
For positive pressures the yield function Φ is deﬁned as:
Φ = σef f − σ0 · (1 − Dc ) − σf · Dc
where:
σ0 = A0 + B0 · p
σf = Af + Bf · p
IMPETUS Afea Solver v.3.0
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Material proper es
Further, σef f is the eﬀective von Mises stress, p is the pressure and Dc is a crushing damage parameter ranging
from 0 to 1. The inelastic ﬂow direction is deﬁned as:
∂Φ
˙pvol = β λ˙
∂p
∂Φ
˙pdev = λ˙
∂σef f
Here pvol is a volumetric crushing strain and pdev is a deviatoric inelastic shear strain. 0 < β ≤ 1 is controlling the amount of volumetric dilatation during plastic ﬂow. Note that β must be larger than 0 as the
evolution of the crushing damage parameter Dc is driven by pvol .
Dc = min(1,
pvol
)
f
A brittle failure criterion is used for p < 0. Cracks initiate once a damage parameter, Ds , has evolved from 0 to 1.

 1 σ1 αs
·( )
σ1 ≥ σs
˙
Ds =
t
σ
 s 0s
σ <σ
1
s
where σ1 is the maximum principal stress and σs is the spall stress.
σs = [A0 · (1 − Dc ) + Af · Dc ] · (1 − D0 )
D0 is an optional initial defect (damage) value that can be deﬁned through INITIAL DAMAGE RANDOM[/ref]
or [ref]INITIAL DAMAGE SURFACE RANDOM. Accounting for initial defects is essential for a physically realistic
behavior of many brittle materials. It is generally more important when dealing with relatively small material
volumes.
Crack propagation is controlled by a stress intensity criterion. The stress intensity KI is estimated for the integration points surrounding the crack tip. The crack will propagate if KI > Kc (Modus I crack).
The pressure-volume relationship is cubic in compression:
p = K1 (µ + pvol ) + K2 µ2 + K3 µ3 µ > 0
and linear in tension:
p = K1 (µ + pvol ) µ < 0
where:
µ = ρ/ρ0 − 1
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Material proper es
Figure 18: Yield stress as a function of pressure and damage
IMPETUS Afea Solver v.3.0
70
Material proper es
*MAT CREEP
*MAT CREEP
mid, ρ, E, ν, did, tid
A, B, n, c0 , c1 , c2 , c3
Parameter deﬁni on
Variable
Description
mid
ρ
E
Unique material identiﬁcation number
Density
Young’s modulus, constant of function of temperature
options: constant, fcn
Poisson’s ratio, constant of function of temperature
options: constant, fcn
Damage property command ID
Thermal property command ID
Initial yield strength, constant or function of temperature
options: constant, fcn
Hardening parameter, constant of function of temperature
options: constant, fcn
Hardening exponent, constant of function of temperature
options: constant, fcn
Creep parameter, constant of function of temperature
options: constant, fcn
Creep parameter, constant of function of temperature
options: constant, fcn
Creep parameter, constant of function of temperature
options: constant, fcn
Creep parameter, constant of function of temperature
options: constant, fcn
ν
did
tid
A
B
n
c0
c1
c2
c3
Descrip on
This model combines a plastic yield surface (J2) with a visco-plastic creep law. All inelastic ﬂow follows a simple
radial return law. The total strain is assumed additive:
= e + p + c
where e stands for elastic, p plastic and c for creep. The plastic yield stress is:
[
]n(T )
σy = A(T ) + B(T ) pef f
The creep strain rate is:
IMPETUS Afea Solver v.3.0
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Material proper es
[
˙cef f
σef f
=
c1 (T ) + c2 (T )cef f + c3 (T )(cef f )2
]c0 (T )
The hydrostatic pressure p is deﬁned as:
p = −Kv + 3KαT (T − Tref )
where K is the bulk modulus, v is the volumetric strain. αT is the thermal expansion coeﬃcient and Tref
is the reference temperature (see PROP THERMAL).
IMPETUS Afea Solver v.3.0
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Material proper es
*MAT ELASTIC
*MAT ELASTIC
mid, ρ, E, ν, did, tid
a, b, c, cdec
Parameter deﬁni on
Variable
Description
mid
ρ
E
ν
did
tid
a, b
c
cdec
Unique material identiﬁcation number
Density
Young’s modulus
Poisson’s ratio
Damage property command ID
Thermal property command ID
Non-linear elasticity parameters
Damping coeﬃcient
Damping decay coeﬃcient
Descrip on
A non-linear elastic constitutive model with damping. The stress is deﬁned as:
∫ t
c
geo 2
σ = −pI + 2G · [1 + ageo
+
b(
)
]
·
+
(τ
˙ ) · e(τ −t)/cdec dτ
dev
dev
dev
cdec 0
G is the shear modulus, dev is the deviatoric strain and geo
dev is the eﬀective deviatoric geometric strain.
√
2
geo
dev =
dev : dev
3
The hydrostatic pressure p is deﬁned as:
p = −Kv + 3KαT (T − Tref )
where K is the bulk modulus, v is the volumetric strain. αT is the thermal expansion coeﬃcient and Tref
is the reference temperature (see PROP THERMAL).
IMPETUS Afea Solver v.3.0
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Material proper es
*MAT FLUID
*MAT FLUID
mid, ρ, K, µ, pc
G
Parameter deﬁni on
Variable
Description
mid
ρ
K
µ
pc
Unique material identiﬁcation number
Density
Linear bulk modulus
Viscosity
Pressure cut-oﬀ
default: -1.0e15
Artiﬁcial shear modulus (Finite elements only)
default: no artiﬁcal shear stiﬀness
G
Descrip on
This is a simple ﬂuid model. It can be combined with an equation-of-state for a non-linear pressure-volume
relationship.
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Material proper es
*MAT FOAM
*MAT FOAM
mid, ρ, E, ν, did
cid, tsc, β
Parameter deﬁni on
Variable
Description
mid
ρ
E
ν
did
cid
Unique material identiﬁcation number
Density
Young’s modulus
Poisson’s ratio
Damage property command ID
ID of a CURVE[/ref] or [ref]FUNCTION deﬁning yield stress versus volumetric compression
Tensile stress cut-oﬀ (a positive value should be given)
Damping coeﬃcient for strain rate sensitivity (β > 0.1 is recommended)
tsc
β
Descrip on
MAT FOAM is a simple model for crushable foams. This model is limited to isotropic behaviour under impact
loading conditions (non-cyclic loading).
Figure 19: Stress-strain behaviour
The implementation assumes a constant Young’s modulus (E) and elastic behaviour for stress update. Trial
stress is thus evaluated as:
1
1
trial
n
σij
= σij
+ 3K( ∆kk δij ) + 2G(∆ij − ∆kk δij )
3
3
where K is the bulk modulus and G is the shear modulus.
Principal stresses σItrial (I=1,3) are then computed and the following criterion is checked:
σ trial
trial σI > σcompaction ⇒ σIn+1 = σcompaction Itrial σI
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Material proper es
The compaction curve is deﬁned by a CURVE (compaction pressure/volumetric strain). This is done independently in each direction, implying no Poisson eﬀect.
Principal stresses are optionally limited in tension by a tension cut-oﬀ parameter (elastic perfectly plastic behaviour).
A damping coeﬃcient is also possibly deﬁned in order to take into account rate sensitivity. Minimal recommended
damping coeﬃcient value is 0.1. This adds an extra damping stress as follows:
damping
σij
= β · ρ · Lelement · clong · i˙j
where β is the damping coeﬃcient, ρ is the density, Lelement is the characteristic element length and clong
is the longitudinal sound speed.
IMPETUS Afea Solver v.3.0
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Material proper es
*MAT FORMING
*MAT FORMING
mid, ρ, E, ν, did, tid
cid, ξ, a0 , a1
1 , 2 , 3 , σ1 , σ2 , σ3 , csysid
Parameter deﬁni on
Variable
Description
mid
ρ
E
ν
did
tid
cid
Unique material identiﬁcation number
Density
Young’s modulus
Poisson’s ratio
Damage model ID
Thermal property command ID
ID of a CURVE[/ref] or [ref]FUNCTION deﬁning yield stress versus plastic strain (equivalent measures)
Kinematical hardening parameter ranging from 0 to 1
default: 0 (pure iso-tropic hardening)
Plastic hardening parameter
Parameter controlling the shape of the yield surface
Initial principal plastic strains
Initial back stress in principal strain directions
ID of coordinate system that deﬁnes the directions of the initial principal strains and
stresses
default: use global directions
ξ
a0
a1
1 , 2 , 3
σ1 , σ2 , σ3
csysid
Descrip on
A texture-based forming model developed by Impetus Afea. The eﬀective stress is deﬁned as:
√
]
3[ 2
2 +b σ
2
2 +σ
2 +σ
2 )
σef f =
b1 σ
ˆ11 + b2 σ
ˆ22
σ12
ˆ23
ˆ31
3 ˆ33 + 2b0 (ˆ
2
where:
σ
ˆ = Q [σdev − σ ∗ ] Qt
σdev is the deviatoric stress, σ ∗ is the back stress due to kinematical hardening and Q is a tensor that transforms
the stress tensor to principal strain directions. b1 , b2 and b3 are parameters that control the diﬀerence in ﬂow
stress in diﬀerent principal strain directions. This is motivated by crystallographic texture eﬀects.
(
)
|i |
bi = 1 + a1 1 −
atan(ˆ
geo )
ˆgeo
IMPETUS Afea Solver v.3.0
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Material proper es
where ˆgeo is an eﬀective geometric strain measure:
√
ˆgeo =
25 2
( + 22 + 23 )
54 1
The deﬁnition of ˆgeo ensures that the force displacement curve in uni-axial tension does not depend on the
parameter a1 .
b0 is a parameter that ensures a larger ﬂow stress in the principal strain directions than in other loading directions.
This is also motivated by crystallographic texture eﬀects.
b0 = 1 + a0 ˆgeo
The degree of kinematical hardening is controlled by ξ, a parameter ranging from 0 to 1. ξ = 0 results in
pure iso-tropic hardening (growing yield surface) and ξ = 1 in pure kinematical hardening (translating yield
surface). The evolution of the back stress is:
σ˙ ∗ = ξH ˙p
and the radius of the yield surface grows according to:
σ˙ y = (1 − ξ)H ˙p
H is the tangential hardening and it is deﬁned as:
H=
dσy
(σef f = σy )
dpef f
The hydrostatic pressure p is deﬁned as:
p = −Kv + 3KαT (T − Tref )
where K is the bulk modulus, v is the volumetric strain. αT is the thermal expansion coeﬃcient and Tref f is
the reference temperature (see PROP THERMAL).
IMPETUS Afea Solver v.3.0
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Material proper es
*MAT FORMING R
*MAT FORMING R
mid, ρ, E, ν, did, tid
cid, ξ, R00 , R45 , R90
Parameter deﬁni on
Variable
Description
mid
ρ
E
ν
did
tid
cid
Unique material identiﬁcation number
Density
Young’s modulus
Poisson’s ratio
Damage model ID
Thermal property command ID
ID of a CURVE[/ref] or [ref]FUNCTION deﬁning yield stress versus plastic strain (equivalent measures)
Kinematical hardening parameter ranging from 0 to 1
default: 0 (pure iso-tropic hardening)
Lankford coeﬃcient
Lankford coeﬃcient
Lankford coeﬃcient
ξ
R00
R45
R90
Descrip on
This is a plasticity model where kinematical hardening and Lankford parameters can be deﬁned as constants or
as functions of the eﬀective plastic strain. A J2 (von Mises) yield criterion is combined with a non-assiciated ﬂow
rule. The non-associated ﬂow rule is deﬁned to satisfy the given Lankford parameters.
Initial material orientation is deﬁned using either INITIAL MATERIAL DIRECTION[/ref], [ref]INITIAL MATERIAL DIRECTI
or [ref]INITIAL MATERIAL DIRECTION WRAP.
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Material proper es
*MAT GRANULAR CAP
*MAT GRANULAR CAP
mid, ρ, E, ν
max , B , B
cid1 , cid2 , ξ, η, σdev
0
1
Parameter deﬁni on
Variable
Description
mid
ρ
E
ν
cid1
cid2
Unique material identiﬁcation number
Density
Young’s modulus
Poisson’s ratio
ID of a CURVE[/ref] or [ref]FUNCTION deﬁning pressure versus volumetric compaction
ID of a CURVE[/ref] or [ref]FUNCTION deﬁning deviatoric yield stress due to grain
adhesion
default: no adhesion
Parameter controlling the shape of the yield surface
Parameter controlling the shape of the yield surface
Upper cap to deviatoric yield strength
default: no upper cap
Failure parameter
default: no failure
Failure parameter
default: 0
ξ
η
max
σdev
B0
B1
Descrip on
This is a material model for granular media, where inelastic deviatoric ﬂow and volumetric ﬂow are coupled. The
shape of the yield surface is shown in the ﬁgure below. Note that the yield surface is split into two regions (I)
and (II). Volumetric ﬂow (compaction) is assumed to only occur in region II (associated ﬂow). Plastic ﬂow in
region I is purely deviatoric (J2). In region II the surface is elliptic:
v(
)
u
u σ ef f 2 ( p − ξp )2
c
t
dev
+
−1
Φ=
ξpc
pc − ξpc
cid1 describes the compaction pressure as function of the eﬀective volumetric strain:
f
pc = pˆc (ef
vol ).
cid2 describes the grain adhesion due to compaction (see yield surface in ﬁgure):
f
σa = σ
ˆa (ef
vol ).
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Material proper es
Damage D is assumed to grow at inelastic deviatoric deformations in region I:
˙ef f
D˙ = dev
B0
(
)
p B1
1−
pc
Damage falls back to zero whenever the material undergoes further compaction (region II). As D reaches 1
the adhesive components of the yield stress are set to zero and pressure is not allowed to drop below 0.
D is set to 1 (instant failure) if meeting the pressure cut-oﬀ criterion, i.e. if p = −σa .
Figure 20: Yield surface and ﬂow law
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Material proper es
*MAT HJC CONCRETE
*MAT HJC CONCRETE
mid, ρ, G
A, B, n, C, fc , T , ˙0 , efmin
sfmax , pc , µc , pl , µl , D1 , D2 , K1
K2 , K3 , erode
Parameter deﬁni on
Variable
Description
mid
ρ
G
A
B
n
C
fc
T
˙0
efmin
sfmax
pc
µc
pl
µl
D1
D2
K1
K2
K3
erode
Unique material identiﬁcation number
Density
Shear modulus
Cohesive strength parameter
Pressure hardening parameter
Pressure hardening parameter
Strain rate parameter
Compressive strength
Tensile strength
Reference strain rate
Minimum fracture strain
Maximum strength
Crush pressure
Crush volumetric strain
Lock pressure
Lock volumetric strain
Failure strain parameter
Failure strain parameter
Linear bulk stiﬀness term
Quadratic bulk stiﬀness term
Cubic bulk stiﬀness term
Element erosion ﬂag
options:
0 → failed element is not eroded
1 → failed element is eroded
Descrip on
This is the Holmquist-Johnson-Cook concrete model. In the postive pressure regime the deviatoric ﬂow stress σy
is deﬁned as:
[
(
( )N ) (
( ))]
p
˙
σy = f c · min sfmax , A(1 − D) + B
· 1 + Cln
fc
˙0
and in the negative pressure (tensile) regime as:
IMPETUS Afea Solver v.3.0
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Material proper es
(
( ))
˙
σy = f c · A(1 + p/T ) · (1 − D) · 1 + Cln
˙0
where p is the current pressure and 0 ≤ D ≤ 1 is the damage. Damage grows during crushing and deviatoric plastic ﬂow according to:
˙p + µ˙ p
D˙ =
f
˙p and µ˙ p are the deviatoric and volumetric plastic strain rates, respectively. The failure strain f is deﬁned
as:
(
(
) )
p + T D2
f = max efmin , D1
fc
The pressure-volumetric strain relationship is divided into three regions. Region I is linear elastic and is valid from
p = −T to p = pc . The bulk modulus in region I is K0 = pc /µc . Region II is transition region where pressure
grows from pc to pl . The bulk modulus in region II is interpolated linearly from K0 at p = pc to K1 at p = pl .
The material is fully compacted at p = pl . Region III describes the fully compacted material. There are no more
voids and the pressure is deﬁned as:
p = K1 µ
ˆ + K2 µ
ˆ2 + K3 µ
ˆ3
where:
µ
ˆ=
IMPETUS Afea Solver v.3.0
µ − µl
1 + µl
83
Material proper es
*MAT JC
*MAT JC
mid, ρ, E, ν, did, tid
A, B, n, C, m, T0 , Tm , 0
Cp , k
Parameter deﬁni on
Variable
Description
mid
ρ
E
ν
did
tid
A
B
n
C
m
T0
Tm
0
Unique material identiﬁcation number
Density
Young’s modulus
Poisson’s ratio
Damage property command ID
Thermal property command ID
Initial yield strength
Hardening parameter
Hardening parameter
Strain rate hardening parameter
Thermal softening parameter
Ambient temperature
Melting temperature
Strain rate parameter
default: 1
Speciﬁc heat capacity
Plastic work to heat conversion factor
default: 0.9
Cp
k
Descrip on
Johnson-Cook’s constitutive model. The von Mises ﬂow stress is deﬁned as:
(
( p )) (
(
) )
(
)
˙ef f
T − T0 m
p
n
σy = A + B(ef f ) · 1 + C · ln
· 1−
0
Tm − T0
T is the current temperature. The hydrostatic pressure p is deﬁned as:
p = −Kv + 3KαT (T − Tref )
where K is the bulk modulus, v is the volumetric strain. αT is the thermal expansion coeﬃcient and Tref
is the reference temperature (see PROP THERMAL).
IMPETUS Afea Solver v.3.0
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Material proper es
*MAT JC FIELD
*MAT JC FIELD
mid, ρ, E, ν, did, tid
A, B, n, C, m, T0 , Tm , 0
Cp , k, Wc0 , c1 , c2 , erode
Parameter deﬁni on
Variable
Description
mid
ρ
E
ν
did
tid
A
B
n
C
m
T0
Tm
0
Unique material identiﬁcation number
Density
Young’s modulus
Poisson’s ratio
Damage property command ID
Thermal property command ID
Initial yield strength
Hardening parameter
Hardening parameter
Strain rate hardening parameter
Thermal softening parameter
Ambient temperature
Melting temperature
Strain rate parameter
default: 1
Speciﬁc heat capacity
Plastic work to heat conversion factor
default: 0.9
Cockcroft-Latham damage parameter
default: damage not active
Extended rate dependency parameter to the Cockcroft-Latham damage criterion
default: not active
Extended rate dependency parameter to the Cockcroft-Latham damage criterion
default: not active
Element erosion ﬂag
options:
0 → failed elements keep the bulk stiﬀness
1 → failed elements are eroded
2 → node splitting
Cp
k
Wc0
c1
c2
erode
Descrip on
Field version of Johnson-Cook’s constitutive model. All parameters (including density) can be functions or parameters. A function can be deﬁned to depend on the initial integration point location (x, y, z). A function is
referenced by typing fcn(id), where id is the function ID.
The von Mises ﬂow stress is deﬁned as:
(
( p )) (
(
) )
(
)
˙ef f
T − T0 m
p
n
σy = A + B(ef f ) · 1 + C · ln
· 1−
0
Tm − T0
IMPETUS Afea Solver v.3.0
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Material proper es
T is the current temperature. The hydrostatic pressure p is deﬁned as:
p = −Kv + 3KαT (T − Tref )
where K is the bulk modulus, v is the volumetric strain. αT is the thermal expansion coeﬃcient and Tref f is
the reference temperature (see PROP THERMAL).
Failure modeling is currently limited to a Cockcroft-Latham criterion that has been extended to account for rate
eﬀects. Failure occurs once the damage parameter, D, has evolved from 0 to 1.
∫
D=
0
IMPETUS Afea Solver v.3.0
pef f
max(0, σ1 )
dpef f
p
c
2
Wc0 · (1 + c1 ˙ef f )
86
Material proper es
*MAT JH CERAMIC
*MAT JH CERAMIC
mid, ρ, G
A, B, C, m, n, ˙0 , T
HEL, pH , β, D1 , D2 , K1 , K2 , K3
erode
Parameter deﬁni on
Variable
Description
mid
ρ
G
A
B
C
m
n
˙0
T
HEL
pH
β
Unique material identiﬁcation number
Density
Shear modulus
Yield surface parameter
Failure surface parameter
Strain rate parameter
Failure surface parameter
Yield surface parameter
Reference strain rate
Strength in hydrostatic tension
Uni-axial stress at Hugoniot elastic limit
Pressure at Hugoniot elastic limit
Fraction of elastic energy loss due to damage that is converted to hydrostatic energy
(pressure)
Failure strain parameter
Failure strain parameter
Linear bulk stiﬀness term
Quadratic bulk stiﬀness term
Cubic bulk stiﬀness term
Element erosion ﬂag
options:
0 → failed element is not eroded
1 → failed element is eroded
D1
D2
K1
K2
K3
erode
Descrip on
The Johnson-Holmquist ceramic model (JH-2) is used to model brittle materials having a higher strength in
compression than in tension. The yield criterion and ﬂow rule follow J2 plasticity. A bulking pressure term is
added to account for dilataion during deviatoric plastic ﬂow. The ﬁgure below shows the von Mises yield stress
as function of pressure and damage.
Damage evolves according to:
D˙ =
˙pef f
f ail
where:
IMPETUS Afea Solver v.3.0
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Material proper es
Figure 21: Eﬀective ﬂow stress as a function of pressure and damage
(
f ail = D1
T +p
pHEL
)D2
The elastic pressure-volume relationship is cubic in compression:
pelastic = K1 µ + K2 µ2 + K3 µ3 µ > 0
and linear in tension:
pelastic = K1 µ µ < 0
where:
µ = ρ/ρ0 − 1
It is assumed that a fraction β of the elastic deviatoric strain energy that is being released as damage grows is
transformed into pressure (the rest dissipates into heat). This is the so called bulking pressure. Assuming an
incremental release of elastic deviatoric strain energy ∆U , the incremental bulking pressure is deﬁned as:
∆pbulk =
√
p2 + 2βK1 ∆U − p
Here p is the total pressure:
p = pelastic + pbulk
IMPETUS Afea Solver v.3.0
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Material proper es
*MAT LIBRARY
*MAT LIBRARY
”material name”, mid
Parameter deﬁni on
Variable
Description
”material name”
mid
Unique name as given in Materials library
Material ID
Descrip on
Includes material from Materials library.
IMPETUS Afea Solver v.3.0
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Material proper es
*MAT METAL
*MAT METAL
mid, ρ, E, ν, did, tid
cid, ξ, tresca, c, 0 , m, T0 , Tm
s0 , s1
Parameter deﬁni on
Variable
Description
mid
ρ
E
ν
did
tid
cid
Unique material identiﬁcation number
Density
Young’s modulus
Poisson’s ratio
Damage property command ID
Thermal property command ID
ID of a CURVE[/ref] or [ref]FUNCTION deﬁning yield stress versus plastic strain (equivalent measures)
Kinematical hardening parameter ranging from 0 to 1
default: 0 (pure iso-tropic hardening)
Flag to activate Tresca yield criterion
options:
0 → von Mises
1 → Tresca
Strain rate hardening parameter
default: 0
Reference strain rate
default: 1
Thermal softening parameter
default: thermal softening deactivated
Thermal softening reference temperature
default: 0
Melting temperature
default: 1.0d20
Damage softening parameter (threshold damage level)
default: s0 = 1
Damage softening parameter
ξ
tresca
c
0
m
T0
Tm
s0
s1
Descrip on
This is constitutive model for ductile metals with optional thermal softening and strain rate hardening. The yield
stress is deﬁned as:
)c
(
(
) ) (
˙pef f
T − T0 m
p
σy = f (ef f ) · g(D) · 1 −
· 1+
Tm − T0
0
where f (pef f ) is a user deﬁned CURVE[/ref] or [ref]FUNCTION, g(D) is an optional damage softening and
T is the current temperature. g(D), where D is the damage level, is deﬁned as:
IMPETUS Afea Solver v.3.0
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Material proper es


g(D) =
1
D ≤ s0
D − s0
· (s1 − 1) D > s0
 1+
1 − s0
That is, g(D) drops linearly from 1 at D = s0 to s1 at D = 1 (full damage).The hydrostatic pressure p is
deﬁned as:
p = −Kv + 3KαT (T − Tref )
where K is the bulk modulus, v is the volumetric strain. αT is the thermal expansion coeﬃcient and Tref
is the reference temperature (see PROP THERMAL).
IMPETUS Afea Solver v.3.0
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Material proper es
*MAT MOONEY RIVLIN
*MAT MOONEY RIVLIN
mid, ρ, K
C1 , C2 , α1 , β1 , α2 , β2 , α3 , β3
α4 , β4
Parameter deﬁni on
Variable
Description
mid
ρ
K
C1
C2
α1
β1
α2
β2
α3
β3
α4
β4
Unique material identiﬁcation number
Density
Bulk modulus
Shear stiﬀness parameter
Shear stiﬀness parameter
Viscous stiﬀness parameter
Viscous decay parameter
Viscous stiﬀness parameter
Viscous decay parameter
Viscous stiﬀness parameter
Viscous decay parameter
Viscous stiﬀness parameter
Viscous decay parameter
Descrip on
This is a visco-elastic model for rubber materials. The total stress σ is the sum of a rate independent elastic
stress tensor σe and a viscous deviatoric stress tensor σv .
σ = σe + σv
It is to be noted that the viscous stresses are not part of the original Mooney-Rivlin material model. The
rate independent deviatoric response is non-linear and it is controlled by the two parameters C1 and C2 . The
principal stresses are deﬁned as:
2C1
(2λ1 − λ2 − λ3 ) −
3
2C1
σ2 =
(2λ2 − λ3 − λ1 ) −
3
2C1
σ3 =
(2λ3 − λ1 − λ2 ) −
3
σ1 =
2C2
(2/λ1 − 1/λ2 − 1/λ3 ) − p
3
2C2
(2/λ2 − 1/λ3 − 1/λ1 ) − p
3
2C2
(2/λ3 − 1/λ1 − 1/λ2 ) − p
3
where λi , i = [1, 3] are eigenvalues of Cauchy-Green’s right stretch tensor C = FT F. The corresponding principal directions are ni and the rate independent stress tensor σe can be expressed as:
σe =
3
∑
σi ni ⊗ ni
i=1
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Material proper es
The pressure p is a linear function of the volumetric strain v :
p = −Kv
The viscous stresses σv are purely deviatoric and are controlled by parameters αk and βk , k = [1, 4].
σv (t) =
∫
4
∑
2αk
k=1
βk
t
˙dev (τ )e(τ −t)/βk dτ
0
Here t is the current time and ˙dev is the deviatoric strain rate. Note that, given a constant deviatoric strain rate
˙dev , the viscous stress response will asymptotically approach:
lim σv =
t→∞
IMPETUS Afea Solver v.3.0
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∑
2αk ˙dev
k=1
93
Material proper es
*MAT MULTILAYER ORTHOTROPIC
*MAT MULTILAYER ORTHOTROPIC
mid, ρ, E1 , E2 , G12 , ν12
E3 , G13 , G23 , ν13 , ν23 , t , c , erode
ndir, α1 , ..., α7
c
Parameter deﬁni on
Variable
Description
mid
ρ
E1
E2
G12
ν12
E3
G13
G23
ν13
ν23
t
c
erode
Unique material identiﬁcation number
Density
In-plane Young’s modulus (0-direction)
In-plane Young’s modulus (othogonally to 0-direction)
In-plane shear modulus
Poisson’s ratio
Young’s modulus in transverse direction
Transverse shear modulus
Transverse shear modulus
Poisson’s ratio
Poisson’s ratio
Tensile failure strain in ﬁber direction
Compressive failure strain in ﬁber direction
Element erosion ﬂag
options:
0 → failed elements keep the bulk stiﬀness
1 → failed elements are eroded
2 → node splitting
Number of ﬁber directions (up to 7)
Fiber directions for failure check (angles relatively the 0-direction)
Strain rate sensitivity parameter
ndir
α1 , ..., α7
c
Descrip on
This is an orthototropic composite model where failure can occur in up to 7 diﬀerent ﬁber directions. The stress
can be expressed as:
σ = L : + c˙
where L is the tangential stiﬀness of the material (fourth order tensor). Failure occurs if the tensile or compressive strain in a ﬁber direction exceeds t and c , respectively. All deviatoric stresses are set to zero at ﬁber
failure.
Initial ﬁber directions need to be deﬁned using either INITIAL MATERIAL DIRECTION[/ref], [ref]INITIAL MATERIAL DIRE
or [ref]INITIAL MATERIAL DIRECTION WRAP.
IMPETUS Afea Solver v.3.0
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Material proper es
*MAT ORTHOTROPIC
*MAT ORTHOTROPIC
mid, ρ, E1 , E2 , G12 , ν12 , ν23
c, cdec , Xt , Xc , Yt , Yc , β, S
erode, res
Parameter deﬁni on
Variable
Description
mid
ρ
E1
E2
G12
ν12
ν23
c
cdec
Xt
Xc
Yt
Yc
β
S
erode
Unique material identiﬁcation number
Density
Young’s modulus in ﬁber direction
Young’s modulus orthogonally to ﬁber direction
In-plane shear modulus
Poisson’s ratio
Poisson’s ratio
Strain rate sensitivity parameter
Strain rate sensitivity decay coeﬃcient
Ultimate tensile stress in ﬁber direction
Ultimate compressive stress in ﬁber direction
Ultimate tensile stress orthogonally to ﬁber direction
Ultimate compressive stress orthogonally to ﬁber direction
Failure parameter
Failure parameter
Element erosion ﬂag
options:
0 → failed element is not eroded
1 → failed element is eroded
Residual strength after failure
default: 0
res
Descrip on
This is an orthototropic composite model. The stress can be expressed as:
∫ t
c
σ =L:+
(τ
˙ ) · e(τ −t)/cdec dτ
cdec 0
where L is the tangential stiﬀness of the material (fourth order tensor). There are four diﬀerent failure criteria.
Fiber tension/shear if σ11 > 0:
D1 = (σ11 /Xt )2 + β(|τ12 |/S)
Fiber compression if σ11 < 0:
IMPETUS Afea Solver v.3.0
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Material proper es
D2 = (σ11 /Xc )2
Matrix tension if σ22 > 0:
D3 = (σ22 /Yt )2 + β(|τ12 |/S)
Matrix compression/shear if σ22 < 0:
D4 = (σ11 /Xc )2 + ((Yc /2S)2 − 1)(σ22 /Yc ) + (τ12 /S)2
All stresses are reduced with the factor res at ﬁber failure, i.e. if D1 ≥ 1. D2 ≥ 1 indicates ﬁber buckling whereby compressive ﬁber stresses (σ11 ) and in plane shear stresses (τ12 ) are reduced with the factor res.
D3 ≥ 1 or D4 ≥ 1 indicates matrix failure and σ22 and τ12 are reduced with the factor res.
Initial ﬁber directions need to be deﬁned using either INITIAL MATERIAL DIRECTION[/ref], [ref]INITIAL MATERIAL DIRE
or [ref]INITIAL MATERIAL DIRECTION WRAP.
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Material proper es
*MAT PWL
*MAT PWL
Descrip on
Has been renamed to MAT METAL.
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Material proper es
*MAT RIGID
*MAT RIGID
mid, ρ
Parameter deﬁni on
Variable
Description
mid
ρ
Unique material identiﬁcation number
Density
Descrip on
Rigid material.
IMPETUS Afea Solver v.3.0
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Material proper es
*MAT USER JS
*MAT USER JS
mid, ρ, E, ν
cmat7 , ... , cmat14
cmat15 , ... , cmat22
cmat23 , ... , cmat30
cmat31 , ... , cmat38
cmat39 , ... , cmat46
cmat47 , ... , cmat54
cmat55 , ... , cmat62
Parameter deﬁni on
Variable
Description
mid
ρ
E
ν
cmat7 , ...
cmat15 ,
cmat22
cmat23 ,
cmat30
cmat31 ,
cmat38
cmat39 ,
cmat46
cmat47 ,
cmat54
cmat55 ,
cmat62
, cmat14
...
,
Unique material identiﬁcation number
Density
Young’s modulus
Poisson’s ratio
Custom material properties
Custom material properties
...
,
Custom material properties
...
,
Custom material properties
...
,
Custom material properties
...
,
Custom material properties
...
,
Custom material properties
Descrip on
User deﬁned material model in javascript.
IMPETUS Afea Solver v.3.0
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Material proper es
*MAT USER X
*MAT USER X
mid, ρ, E, ν
cmat7 , ... , cmat14
cmat15 , ... , cmat22
cmat23 , ... , cmat30
cmat31 , ... , cmat38
cmat39 , ... , cmat46
cmat47 , ... , cmat54
cmat55 , ... , cmat62
Parameter deﬁni on
Variable
Description
mid
ρ
E
ν
cmat7 , ...
cmat15 ,
cmat22
cmat23 ,
cmat30
cmat31 ,
cmat38
cmat39 ,
cmat46
cmat47 ,
cmat54
cmat55 ,
cmat62
, cmat14
...
,
Unique material identiﬁcation number
Density
Young’s modulus
Poisson’s ratio
Custom material properties
Custom material properties
...
,
Custom material properties
...
,
Custom material properties
...
,
Custom material properties
...
,
Custom material properties
...
,
Custom material properties
Descrip on
User deﬁned material model for fortran compiled DLL.
IMPETUS Afea Solver v.3.0
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Material proper es
*MAT VISCO PLASTIC
*MAT VISCO PLASTIC
mid, ρ, E, ν, did, tid
σ0 , Q1 , C1 , Q2 , C2 , cid, cdec , α
β, m, T0 , Tm
Parameter deﬁni on
Variable
Description
mid
ρ
E
ν
did
tid
σ0
Q1
C1
Q2
C2
cid
cdec
α
β
m
T0
Tm
Unique material identiﬁcation number
Density
Young’s modulus
Poisson’s ratio
Damage property command ID
Thermal property command ID
Initial yield stress
Voce hardening coeﬃcient
Voce hardening coeﬃcient
Voce hardening coeﬃcient
Voce hardening coeﬃcient
ID of a FUNCTION[/ref] or [ref]CURVE deﬁning the viscosity of the material
Viscous stress decay coeﬃcient
Non-linear elastic stifness coeﬃcient
Plastic ﬂow stress triaxiality factor
Thermal softening parameter
Thermal softening reference temperature
Thermal softening melting temperature
Descrip on
This is a non-linear visco-plastic constitutive model where the total stress σ is the sum of three terms:
σ = σ1 + σ2 + σ3
σ 1 is a non-linear viscous stress, σ 2 is a non-linear elastic stress and σ 3 is a linear elastic stress component.
The rheological model is depicted below.
The non-linear viscous stress σ 1 is deﬁned as:
σ 1 = f (�˙ , ) · �˙
where f is a user deﬁned FUNCTION[/ref] or [ref]CURVE with ID cid. FUNCTION allows the viscosity to
depend on both the eﬀective geometric strain and the strain rate. If using a CURVE, the viscosity is a function
of ¯˙ only. ¯˙ is a smeared out strain rate measure:
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Material proper es
Figure 22: Rheological model for MAT VISCO PLASTIC
1
_
�
(t) =
cdec
∫
t
(τ
˙ )e−τ /cdec dτ
0
Note that ¯˙ = ˙ if cdec = 0. The non-linear elastic stress σ 2 is deﬁned to grow quadratically with the total
deviatoric strain dev :
(
2
σ = 2αG
2
dev : dev
3
)1/2
· dev
G is the linear shear modulus. The linear elastic stress component σ 3 is deﬁned as:
σ 3 = −pI + 2Gedev
p is the hydrostatic pressure and edev is the deviatoric part of the linear elastic strain tensor e in the relation:
= e + p
where p is a plastic strain tensor. The plasticity model is based on a von Mises eﬀective stress deﬁnition
and an iso-choric plastic ﬂow law. The plastic yield stress is deﬁned as:
[
] [
] [
]
2
∑
T − T0 m
βp
−Ci pef f
σy = σ0 +
Qi (1 − e
) · 1−
· 1+
Tm − T0
σ0
i=1
Note that β 6= 0 leads to a pressure dependent yield stress. β 6= 0 and an iso-choric plastic ﬂow makes the
ﬂow rule non-associated. The hydrostatic pressure p is deﬁned as:
p = −Kv + 3KαT (T − Tref )
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Material proper es
where K is the linear bulk modulus, v is the volumetric strain. αT is the thermal expansion coeﬃcient and Tref
is the reference temperature (see PROP THERMAL).
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Material proper es
*PROP DAMAGE BRITTLE
*PROP DAMAGE BRITTLE
did, erode, noic
σs , Kc , ts , αs
Parameter deﬁni on
Variable
Description
did
erode
Unique damage identiﬁcation number
Element erosion ﬂag
options:
0 → failed element is not eroded
1 → failed element is eroded
2 → node splitting at failure (crack plane orthogonal to max principal strain)
3 → node splitting at failure (crack plane orthogonal max principal stress)
Flag to turn oﬀ cracking along interface between diﬀerent materials
options:
0 → material interface cracks are allowed
1 → material interface cracks are not allowed
Threshold stress (maximum principal stress) for initiation of fracture.
Stress intensity factor for crack propagation (only used with node splitting)
default: not used
Time to initiate fracture at threshold stress
default: not used
Exponent controlling time to initiate fracture
default: not used
noic
σs
Kc
ts
αs
Descrip on
This is a brittle fracture criterion. The material cracks once the damage parameter, D, has evolved from 0 to 1.
The damage is deﬁned as:
∫
1 t
D=
(σ1 /σs )αs dt
ts 0
where σ1 is the maximum principal stress. Note that the damage only grows if σ1 ≥ σs . Crack propagation is controlled by a stress intensity criterion (if having node splitting activated). The stress intensity KI is
estimated for the integration points surrounding the crack tip. The crack will propagate if KI > Kc (Modus I
crack).
IMPETUS Afea Solver v.3.0
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Material proper es
*PROP DAMAGE CL
*PROP DAMAGE CL
did, erode, noic
Wc , GI , σs , ts , αs
Parameter deﬁni on
Variable
Description
did
erode
Unique damage identiﬁcation number
Element erosion ﬂag
options:
0 → failed element is not eroded
1 → failed element is eroded
2 → node splitting at failure (crack plane orthogonal to max principal strain)
3 → node splitting at failure (crack plane orthogonal max principal stress)
Flag to turn oﬀ cracking along interface between diﬀerent materials
options:
0 → material interface cracks are allowed
1 → material interface cracks are not allowed
Damage parameter. If referring to a function (see FUNCTION STATIC) the damage
parameter can be deﬁned to depend on the location
options: constant, fcn
Fracture energy parameter (only used with node splitting)
default: not used
Spall strength (threshold stress)
default: not used
Time to develop spall fracture at threshold stress
default: not used
Exponent controlling time to develop spall fracture
default: not used
noic
Wc
GI
σs
ts
αs
Descrip on
This is the Cockcroft-Latham failure criterion. It has been complemented with a tensile fracture/spalling crierion.
The material will lose its shear strength once the damage parameter, D, has evolved from 0 to 1. The damage
is deﬁned as:
D=
1
Wc
∫
pef f
0
max(0, σ1 )dpef f +
1
ts
∫
t
(σ1 /σs )αs dt
0
where σ1 is the maximum principal stress. Note that the tensile fracture/spalling term only contributes to
the damage growth if σ1 ≥ σs .
IMPETUS Afea Solver v.3.0
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Material proper es
*PROP DAMAGE CL ANISOTROPIC
*PROP DAMAGE CL ANISOTROPIC
did, erode, noic
W0 , W90 , Wt
Parameter deﬁni on
Variable
Description
did
erode
Unique damage identiﬁcation number
Element erosion ﬂag
options:
0 → failed element is not eroded
1 → failed element is eroded
2 → node splitting at failure (crack plane orthogonal to max principal strain)
3 → node splitting at failure (crack plane orthogonal max principal stress)
Flag to turn oﬀ cracking along interface between diﬀerent materials
options:
0 → material interface cracks are allowed
1 → material interface cracks are not allowed
Damage parameter for the rolling/extrusion direction
Damage parameter for the transverse direction
Damage parameter for the material thickness direction
noic
W0
W90
Wt
Descrip on
This is an anisotropic Cockcroft-Latham like failure criterion. The material will fail once the damage parameter,
D, has evolved from 0 to 1.
∫
D=
0
pef f
max(0, σ1 ) p
def f
Wc
where σ1 is the maximum principal stress. Wc is a weighted ductility parameter and it depends on the loading
direction:
√
2 cos2 α + W 2 cos2 α
Wc = W02 cos2 α0 + W90
90
t
t
α0 , α90 and αt are the angles between the maximum principle stress and the material rolling/extrusion, transverse
and thickness directions, respectively.
The initial material orientation is deﬁned using either INITIAL MATERIAL DIRECTION[/ref], [ref]INITIAL MATERIAL DIRE
or [ref]INITIAL MATERIAL DIRECTION WRAP.
IMPETUS Afea Solver v.3.0
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Material proper es
*PROP DAMAGE IMP
*PROP DAMAGE IMP
did, erode, noic
Wc , n
Parameter deﬁni on
Variable
Description
did
erode
Unique damage identiﬁcation number
Element erosion ﬂag
options:
0 → failed element is not eroded
1 → failed element is eroded
2 → node splitting at failure (crack plane orthogonal to max principal strain)
3 → node splitting at failure (crack plane orthogonal max principal stress)
Flag to turn oﬀ cracking along interface between diﬀerent materials
options:
0 → material interface cracks are allowed
1 → material interface cracks are not allowed
Damage parameter
Damage growth exponent
noic
Wc
n
Descrip on
IMPETUS failure criterion is similar to the Cockcroft-Latham failure criterion. However, it has been equipped
with one extra parameter n that allows for an anisotropic damage growth. The model is based on the assumption
that defects deform with the material. It is further assumed that compressed defects exposed to tensile loading are
more harmful than elongated defects. The damage growth is assumed proportional to the maximum eigenvalue
σ
ˆ1 of a distorted stress tensor σ
ˆ.
1
D=
Wc
∫
pef f
0
max(0, σ
ˆ1 )dpef f
The distorted stress tensor σ
ˆ is formed as:
σ
ˆ = AσA
where σ is the current stress tensor and A is a symmetric tensor describing the defect compression. A is a
function of the principal stretches (λ1 , λ2 , λ3 ) and of their corresponding eigenvectors (v1 , v2 , v3 ).
A=
)
3 (
∑
λ1 n
i=1
λi
vi ⊗ vi
Note that λ1 is the maximum principal stretch. The formulation ensures that the damage growth is equivialent to Cockcroft-Latham in proportional loading where λ1 coincides with σ1 .
IMPETUS Afea Solver v.3.0
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Material proper es
*PROP DAMAGE IMP ISO
*PROP DAMAGE IMP ISO
did, erode, noic
Aimp , Bimp , Wimp
Parameter deﬁni on
Variable
Description
did
erode
Unique damage identiﬁcation number
Element erosion ﬂag
options:
0 → failed element is not eroded
1 → failed element is eroded
2 → node splitting at failure (crack plane orthogonal to max principal strain)
3 → node splitting at failure (crack plane orthogonal max principal stress)
Flag to turn oﬀ cracking along interface between diﬀerent materials
options:
0 → material interface cracks are allowed
1 → material interface cracks are not allowed
Damage parameter
Damage parameter
Damage parameter
noic
Aimp
Bimp
Wimp
Descrip on
This is the IMPETUS isotropic failure criterion. The material will lose its shear strength pressure once the damage
parameter, D, has evolved from 0 to 1. The damage is deﬁned as:
]
[
∫ p
ef f
1
p
p
Aimp
max(0, σ1 )def f + Bimp σ1 ef f
D=
Wimp
0
where σ1 is the maximum principal stress.
IMPETUS Afea Solver v.3.0
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Material proper es
*PROP DAMAGE JC
*PROP DAMAGE JC
did, erode, noic
d1 , d2 , d3 , d4 , d5 , 0 , T0 , Tm
Parameter deﬁni on
Variable
Description
did
erode
Unique damage identiﬁcation number
Element erosion ﬂag
options:
0 → failed element is not eroded
1 → failed element is eroded
2 → node splitting at failure (crack plane orthogonal to max principal strain)
3 → node splitting at failure (crack plane orthogonal max principal stress)
Flag to turn oﬀ cracking along interface between diﬀerent materials
options:
0 → material interface cracks are allowed
1 → material interface cracks are not allowed
Damage parameters
Reference strain rate
default: 1
Reference and melting temperatures
noic
d1 , d2 , d3 , d4 , d5
0
T0 , Tm
Descrip on
This is the Johnson-Cook failure criterion. The material will lose its shear strength pressure once the damage
parameter, D, has evolved from 0 to 1. The damage growth rate is deﬁned as:
D˙ =
˙pef f
f
where:
|d3 | p
f = (d1 + d2 · e σef f ) · (1 + d4 · ln(
˙pef f
0
)) · (1 + d5 · (
T − T0
))
Tm − T0
and:
p = −(σxx + σyy + σzz )/3
IMPETUS Afea Solver v.3.0
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Material proper es
*PROP DAMAGE STRAIN
*PROP DAMAGE STRAIN
did, erode, noic
t
c
vol
geo
f ail , f ail , f ail , f ail
Parameter deﬁni on
Variable
Description
did
erode
Unique damage identiﬁcation number
Element erosion ﬂag
options:
0 → failed element is not eroded
1 → failed element is eroded
2 → node splitting at failure (crack plane orthogonal to max principal strain)
3 → node splitting at failure (crack plane orthogonal max principal stress)
Flag to turn oﬀ cracking along interface between diﬀerent materials
options:
0 → material interface cracks are allowed
1 → material interface cracks are not allowed
Eﬀective geometrical failure strain
default: not active
Tensile failure strain
default: not active
Compressive failure strain
default: not active
Volumetric failure strain
default: not active
noic
geo
f ail
tf ail
cf ail
vol
f ail
Descrip on
Various strain failure criteria. The material will lose its shear strength pressure once at least one of the criteria
is met. The eﬀective geometrical strain deﬁnition is:
√
2
geo
=
:
3
IMPETUS Afea Solver v.3.0
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Material proper es
*PROP THERMAL
*PROP THERMAL
tid, αT , Cp , λ, k, Tref
Parameter deﬁni on
Variable
Description
tid
αT
Cp
λ
k
Unique thermal property identiﬁcation number
Heat expansion coeﬃcient
Heat capacity
Heat conductivity
Plastic work heat conversion factor
default: 0.9
Reference temperature for thermal expansion
Tref
Descrip on
Thermal property command. It is to be referenced from a material command.
IMPETUS Afea Solver v.3.0
111
Ini al condi ons
Ini al condi ons
*INITIAL
*INITIAL
*INITIAL
*INITIAL
*INITIAL
*INITIAL
*INITIAL
*INITIAL
*INITIAL
*INITIAL
*INITIAL
DAMAGE RANDOM
DAMAGE SURFACE RANDOM
MATERIAL DIRECTION
MATERIAL DIRECTION VECTOR
MATERIAL DIRECTION WRAP
STATE
STATE HAZ
STATE WELDSIM
STRESS FUNCTION
TEMPERATURE
VELOCITY
IMPETUS Afea Solver v.3.0
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Ini al condi ons
*INITIAL DAMAGE RANDOM
*INITIAL DAMAGE RANDOM
entype, enid, a, b, Dmax , R, cid
Parameter deﬁni on
Variable
Description
entype
Entity type
options: M, P, PS
Entity ID
Defect distribution parameter
Defect distribution parameter
Maximum initial damage
Optional imperfection radius
ID of a CURVE[/ref] or [ref]FUNCTION deﬁning yield stress (sigy0) as function of initial
damage
default: not used
enid
a
b
Dmax
R
cid
Descrip on
This command is used to deﬁne a randomly distributed initial damage. A distribution function f (D) describes
the number of defects per unit volume of matter.
{
a · e−bD D ≤ Dmax
f (D) =
0
D > Dmax
Note that the maximum initial damage cannot be larger than Dmax . The number of defects N per unit volume
of matter in the range D0 to Dmax can be calculated by integrating f (D) from D0 to Dmax :
∫
Dmax
N=
f (D)dD
D0
Based on the assumed damage distribution f (D) one can show that the probability p of having at least one
initial defect larger than or equal to D0 in a volume v is:
p = 1 − e−N ·v
This probability expression can be used to assign an initial damage level to to each integration point in the
model. The damage level is obtained by solving the expression for D0 (given a random number p and an
integration point volume v).
IMPETUS Afea Solver v.3.0
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Ini al condi ons
*INITIAL DAMAGE SURFACE RANDOM
*INITIAL DAMAGE SURFACE RANDOM
entype, enid, ∆0 , m, Dmax , R, cid
Parameter deﬁni on
Variable
Description
entype
Entity type
options: M, P, PS
Entity ID
Defect distribution parameter
Defect distribution parameter
Maximum initial damage
Optional imperfection radius
ID of a CURVE[/ref] or [ref]FUNCTION deﬁning yield stress (sigy0) as function of initial
damage
default: not used
enid
∆0
m
Dmax
R
cid
Descrip on
This command is used to deﬁne randomly distributed initial defects on the surface of a body. The defects are
interpreted as equivalent to an initial damage D. The probability P of having an initial defect larger or equal to
D on a surface A is deﬁned as:

1


[
(
) ] : D=0

1−D m
P (A, D) =
1 − exp −A
: 0 < D ≤ Dmax

∆0


0
: D > Dmax
The variables ∆0 , m and Dmax are input parameters that typically need to be tuned to match experimental
data with a certain spread.
The inverse function D(A, P ) is used to deﬁne the intitial damage level for each integration point near the
material surface. In this context 0 ≤ P ≤ 1 is a random number and A is the area represented by the integration
point.

0



D(A, P ) =
IMPETUS Afea Solver v.3.0



1 − ∆0
Dmax
(
−ln(1 − P )
A
)1/m
: P > P (A, 0)
: P (A, Dmax ) < P ≤ P (A, 0)
: P < P (A, Dmax )
114
Ini al condi ons
Figure 23: Typical initial damage probability function P (A, D) - ∆0 = 0.15, m = 6, Dmax = 0.4, A = 2.0e − 5
Figure 24: Typical initial damage function D(A, P ) - ∆0 = 0.15, m = 6, Dmax = 0.4, A = 2.0e − 5
IMPETUS Afea Solver v.3.0
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Ini al condi ons
*INITIAL MATERIAL DIRECTION
*INITIAL MATERIAL DIRECTION
nid, x
ˆx , x
ˆy , x
ˆz , y¯x , y¯y , y¯z
Parameter deﬁni on
Variable
Description
nid
x
ˆx , x
ˆy , x
ˆz
y¯x , y¯y , y¯z
Node ID
Direction of local x-axis
Vector needed for the deﬁnition of the local y- and z-axis
Descrip on
This command is used to deﬁne local material directions. Data is input for the element corner nodes. The local
directions at the element integration points at time 0 are interpolated from the element corner node values. The
local y-axis (ˆy) and z-axis (ˆz) are deﬁned as:
ˆz =
ˆx × ¯y
|ˆx × ¯y|
ˆy = ˆz × ˆx
Alternative commands for deﬁnitions of local material directions are INITIAL MATERIAL DIRECTION VECTOR[/ref]
and [ref]INITIAL MATERIAL DIRECTION WRAP.
IMPETUS Afea Solver v.3.0
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Ini al condi ons
*INITIAL MATERIAL DIRECTION VECTOR
*INITIAL MATERIAL DIRECTION VECTOR
coid, entype, enid
x
ˆx , x
ˆy , x
ˆz , y¯x , y¯y , y¯z
Parameter deﬁni on
Variable
Description
coid
entype
Command ID
Entity type
options: P, PS
Entity ID
Direction of local x-axis
Optional vector used for the deﬁnition of the local y- and z-axis
enid
x
ˆx , x
ˆy , x
ˆz
y¯x , y¯y , y¯z
Descrip on
This command is used to deﬁne local material directions. If ¯y = (¯
yx , y¯y , y¯z ) has been deﬁned the local and z-axis
(¯z) is computed as:
ˆz =
ˆx × ¯y
|ˆx × ¯y|
If ¯y has not been deﬁned the local z-axis (¯z) is equivalent to:
ˆ
ˆz = n
ˆ is the local element face normal. Note that this option only works if the structure is modeled with
where n
one single element in its thickness direction. Once ˆz has been computed ˆy is calculated as:
ˆy = ˆz × ˆx
All direction parameters can either be constants or deﬁned as functions of the local coordinate (x, y, z).
IMPETUS Afea Solver v.3.0
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Ini al condi ons
*INITIAL MATERIAL DIRECTION WRAP
*INITIAL MATERIAL DIRECTION WRAP
coid, entype, enid
x 0 , y0 , z 0 , u
ˆx , u
ˆy , u
ˆz , α
Parameter deﬁni on
Variable
Description
coid
entype
Command ID
Entity type
options: P, PS
Entity ID
Coordinate used for deﬁnition of the ply location
Vector used for deﬁnition of the ply orientation
Angle used for deﬁnition of ﬁber direction
enid
x0 , y0 , z0
u
ˆx , u
ˆy , u
ˆz
α
Descrip on
This command is used to deﬁne local material directions in ﬁber composites. The user deﬁnes the location and
orientation of a ”ply” in space. This ply is then wrapped around the component.
The ply ﬁrst needs to be projected onto/wrapped around the component. This projection generates intermediate
in-plane directions ¯x and ¯y.
¯y =
ˆ
ˆz × u
ˆ|
|ˆz × u
¯x = ¯y × ˆz
where ˆz is the local face surface normal direction. The local ﬁber direction ˆx and the orthogonal direction ˆy
can now be deﬁned by rotating the intermediate directions with the angle α.
ˆx = cos(α)¯x + sin(α)¯y
ˆy = − sin(α)¯x + cos(α)¯y
IMPETUS Afea Solver v.3.0
118
Ini al condi ons
Figure 25: Deﬁnition of ﬁber direction
IMPETUS Afea Solver v.3.0
119
Ini al condi ons
*INITIAL STATE
*INITIAL STATE
eid, etype, ip, mtype, V0
F11 , F12 , F13
F21 , F22 , F23
F31 , F32 , F33
σ11 , σ22 , σ33 , σ12 , σ23 , σ31
11 , 22 , 33 , 12 , 23 , 31
v01 , ..., v08
v09 , ..., v16
v17 , ..., v24
Parameter deﬁni on
Variable
Description
eid
etype
ip
mtype
V0
F11 , F12 , F13
F21 , F22 , F23
F31 , F32 , F33
σ11 , σ22 , σ33
σ12 , σ23 , σ31
11 , 22 , 33
12 , 23 , 31
v01 , ..., v08
v09 , ..., v16
v17 , ..., v24
Element ID
Element type
Integration point number
Material type
Integration point volume in undeformed state
Deformation gradient components
Deformation gradient components
Deformation gradient components
Stress components
Strain components
State variables 1-8
State variables 9-16
State variables 17-24
Descrip on
Deﬁnition of the initial state (deformation, stresses and state variables) on integration point level. This command
is used by the solver when writing a state ﬁle (impetus stateX.k and impetus stateX.bin) with the complete state
for a set of parts deﬁned in the input deck (see parameter resid in OUTPUT).
IMPETUS Afea Solver v.3.0
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Ini al condi ons
*INITIAL STATE HAZ
*INITIAL STATE HAZ
entypeweld , enidweld , entypebase , enidbase , cidsigy , cidD0
Parameter deﬁni on
Variable
Description
entypeweld
Weld entity type
options: P, PS
Weld entity ID
Base material entity type
options: P, PS
Base material entity ID
ID of a CURVE[/ref] or [ref]FUNCTION describing yield stress as function of the distance
from the weld
default: not used
ID of a CURVE[/ref] or [ref]FUNCTION describing initial damage as function of the
distance from the weld
default: not used
enidweld
entypebase
enidbase
cidsigy
cidD0
Descrip on
This command is used to deﬁne mechanical properties in a HAZ after a welding operation. Initial yield stress and
damage are deﬁned as functions of the distance from the weld. The yield stress can be accessed in FUNCTION
through the built in variable sigy0.
IMPETUS Afea Solver v.3.0
121
Ini al condi ons
*INITIAL STATE WELDSIM
*INITIAL STATE WELDSIM
type, sf1 , ..., sf6
nid1 , v1 , ..., v6
.
nidn , v1 , ..., v6
Parameter deﬁni on
Variable
Description
type
Input type
options: 1 → initial yield stress is imported from WeldSim (TM)
Scale factors
Node identiﬁcation number
Node quantities
Node identiﬁcation number
Node quantities
sf1 , ..., sf6
nid1
v1 , ..., v6
nidn
v1 , ..., v6
Descrip on
This command allows the user to import simulation results from WeldSim (TM), in order to deﬁne the distribution
of material properties in the heat aﬀected zone (HAZ) after a welding operation. The GUI of IMPETUS Afea
Solver can read and visualize result data from WeldSim (TM) and export it to a format that can be handled
by IMPETUS Afea Solver for further computational analysis. Currently only the yield stress can be imported
(type=1). The yield stress can be accessed in FUNCTION through the built in variable sigy0.
IMPETUS Afea Solver v.3.0
122
Ini al condi ons
*INITIAL STRESS FUNCTION
*INITIAL STRESS FUNCTION
entype, enid, ﬁdxx , ﬁdyy , ﬁdzz , ﬁdxy , ﬁdyz , ﬁdzx
multi
Parameter deﬁni on
Variable
Description
entype
Entity type
options: M, P, PS
Entity ID
ID of FUNCTION deﬁning σxx as function of (x, y, z)
ID of FUNCTION deﬁning σyy as function of (x, y, z)
ID of FUNCTION deﬁning σzz as function of (x, y, z)
ID of FUNCTION deﬁning σxy as function of (x, y, z)
ID of FUNCTION deﬁning σyz as function of (x, y, z)
ID of FUNCTION deﬁning σzx as function of (x, y, z)
Treatment of multiple commands
options:
0 → stresses from previous commands are overwritten
1 → stresses from multiple commands are superposed
2 → stress component with largest absolute value is kept
enid
ﬁdxx
ﬁdyy
ﬁdzz
ﬁdxy
ﬁdyz
ﬁdzx
multi
Descrip on
Deﬁnition of initial stresses.
IMPETUS Afea Solver v.3.0
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Ini al condi ons
*INITIAL TEMPERATURE
*INITIAL TEMPERATURE
entype, enid, ﬁd
Parameter deﬁni on
Variable
Description
entype
Entity type
options: P, PS
Entity identiﬁcation number
ID of a FUNCTION deﬁning the temperature ﬁeld
enid
ﬁd
Descrip on
Deﬁnition of an initial temperature ﬁeld.
IMPETUS Afea Solver v.3.0
124
Ini al condi ons
*INITIAL VELOCITY
*INITIAL VELOCITY
entype, enid, vx0 , vy0 , vz0 , ωx , ωy , ωz
x0 , y0 , z0 , δvx , δvy , δvz
Parameter deﬁni on
Variable
Description
entype
Entity type
options: N, NS, P, PS, ALL, G
Entity identiﬁcation number
Initial velocity in x-direction
default: 0
Initial velocity in y-direction
default: 0
Initial velocity in z-direction
default: 0
Initial angular velocity vector
default: (0,0,0)
Center of rotation
default: (0,0,0)
Gradient of velocity ﬁeld
default: (0,0,0)
enid
vx0
vy0
vz0
ωx , ωy , ωz
x0 , y0 , z0
δvx , δvy , δvz
Descrip on
This command is used to deﬁne initial velocities and initial angular velocities, applying to nodes and to soil
particles (see PBLAST). The command is additive and multiple velocity deﬁnitions are summed up to form a
total velocity.
An initial velocity term of a node or a soil particle at coordinate (x, y, z) is deﬁned as:
 
 
 
 


 vx   vx0   x − x0   ωx   δvx (x − x0 ) 
vy
vy0
y − y0
ωy
δvy (y − y0 )
=
+
×
+
 
 
 
 


vz
vz0
z − z0
ωz
δvz (z − z0 )
IMPETUS Afea Solver v.3.0
125
Boundary condi ons
Boundary condi ons
*BC MOTION
*BC SYMMETRY
*BC TEMPERATURE
IMPETUS Afea Solver v.3.0
126
Boundary condi ons
*BC MOTION
*BC MOTION
coid
entype, enid, bctr , bcrot , csysidtr , csysidrot , tbeg , tend
pmeth1 , direc1 , cid1 , sf1
.
pmethn , direcn , cidn , sfn
Parameter deﬁni on
Variable
Description
coid
entype
Command ID (optional)
Entity type
options: N, NS, P, PS, ALL, G
Entity identiﬁcation number
Translational constraints
options: 0, X, Y, Z, XY, YZ, ZX, XYZ
Rotational constraint
options: 0, X, Y, Z, XY, YZ, ZX, XYZ
Coordinate system ID for translational constraints
Coordinate system ID for rotational constraints (negative or 0 for rotation around COG)
Activation time
Termination time
Method used to prescribe motion (acceleration/velocity or displacement)
options: A, V, D
Direction of precsribed motion
options: X, Y, Z, RX, RY, RZ
ID of a CURVE[/ref] or [ref]FUNCTION deﬁning prescribed motion
Scale factor for curve ordinate values
default: 1
Method used to prescribe motion (acceleration/velocity or displacement)
options: A, V, D
Direction of precsribed motion
options: X, Y, Z, RX, RY, RZ
ID of a CURVE[/ref] or [ref]FUNCTION deﬁning prescribed motion
Scale factor for curve ordinate values
default: 1
enid
bctr
bcrot
csysidtr
csysidrot
tbeg
tend
pmeth1
direc1
cid1
sf1
pmethn
direcn
cidn
sfn
Descrip on
Deﬁnition of kinematic boundary conditions. When referring to a local cylindrical coordinate system (csystr), X
corresponds to the radial direction, Y to the tangential direction and Z to the axial direction.
IMPETUS Afea Solver v.3.0
127
Boundary condi ons
*BC SYMMETRY
*BC SYMMETRY
plane, csysid1 , csysid2 , csysid3 , tol
Parameter deﬁni on
Variable
Description
plane
Symmetry planes through the origin
options: X, Y, Z, XY, YZ, ZX, XYZ
IDs of coordinate systems that deﬁne up to 3 diﬀerent symmetry planes (only active if
plane=0)
maximum distance between a node and the symmetry plane for symmetry conditions to
be applied
csysid1 ,
csysid3
tol
csysid2 ,
Descrip on
This command deﬁnes up to three symmetry planes at x, y or z = 0 or at the origin of speciﬁed coordinate
systems. When referring to a local coordinate system, the symmetry plane normal is deﬁned as the local xdirection of the coordinate system. The normal direction of the nearest element face is taken as symmetry plane
normal in case the local x-direction has not been explicitly deﬁned in the coordinate system command.
Appropriate boundary conditions are automatical applied to nodes located on a symmetry plane. External faces
on a symmetry plane are excluded from the contact.
Symmetry conditions are also applied to the boundary of global PBLAST domains.
Symmetry planes can also be used as rigid frictionless walls, that nodes can not penetrate.
IMPETUS Afea Solver v.3.0
128
Boundary condi ons
*BC TEMPERATURE
*BC TEMPERATURE
entype, enid, cid, sf , tbeg , tend
Parameter deﬁni on
Variable
Description
entype
Entity type
options: P, PS
Entity identiﬁcation number
ID of a CURVE[/ref] or [ref]FUNCTION deﬁning temperature versus time
Temperature curve scale factor
default: 1
Start time
default: 0
End time
default: 1.0e10
enid
cid
sf
tbeg
tend
Descrip on
Deﬁnition of temperature boundary condition. Note that the temperature is computed and stored directly at the
integration points.
IMPETUS Afea Solver v.3.0
129
Loads
Loads
*LOAD CENTRIFUGAL
*LOAD DAMPING
*LOAD FORCE
*LOAD GRAVITY
*LOAD PRESSURE
*LOAD SHEAR
*LOAD THERMAL BODY
*LOAD THERMAL SURFACE
*PRESTRESS BOLT
IMPETUS Afea Solver v.3.0
130
Loads
*LOAD CENTRIFUGAL
*LOAD CENTRIFUGAL
entype, enid, cid, csysid, tbeg , tend
Parameter deﬁni on
Variable
Description
entype
Entity type
options: N, NS, P, PS
Entity identiﬁcation number
ID of a CURVE[/ref] or [ref]FUNCTION deﬁning angular velocity versus time
Local coordinate system ID
Start time
End time
default: 1.0e10
enid
cid
csysid
tbeg
tend
Descrip on
This command is used to apply centrifugal forces on a component without actually spinning the model. The
command is typically used to initialize stresses in a rotating fan blade. The local coordinate system is used to
deﬁne the center of rotation and the rotational axis (local x-axis).
IMPETUS Afea Solver v.3.0
131
Loads
*LOAD DAMPING
*LOAD DAMPING
entype, enid, cid, µ, cdec
Parameter deﬁni on
Variable
Description
entype
Entity type
options: N, NS, P, PS, ALL
Entity ID
ID of a CURVE[/ref] or [ref]FUNCTION deﬁning the mass damping coeﬃcient C versus
time
Viscous damping coeﬃcient
Viscous decay coeﬃcient
enid
cid
µ
cdec
Descrip on
This command is used to deﬁne mass damping and viscous damping for a given subset of the model. The mass
damping force Fi acting a node i is deﬁned as:
Fi = −C · mi · vi
where C is the damping coeﬃcient deﬁned by the CURVE[/ref] or [ref]FUNCTION with ID cid, mi is the
node mass and vi is the node velocity. The viscous damping is deﬁned as an artiﬁcial material viscosity. This
viscosity produces an extra, strain rate dependent, stress term σµ :
∫ t
µ
(τ
˙ ) · e(τ −t)/cdec dτ
σµ =
cdec 0
IMPETUS Afea Solver v.3.0
132
Loads
*LOAD FORCE
*LOAD FORCE
entype, enid, direc, cid, sf , csysid, tbeg , tend
Parameter deﬁni on
Variable
Description
entype
Entity type (P only for rigid bodies)
options: N, NS, G, FS, P
Entity identiﬁcation number
Force/moment direction
options: X, Y, Z, RX, RY, RZ
ID of a CURVE[/ref] or [ref]FUNCTION deﬁning force/moment versus time
Force/moment scale factor
default: 1
Local coordinate system ID
default: global coordinates are used
Start time
End time
default: 1.0e10
enid
direc
cid
sf
csysid
tbeg
tend
Descrip on
This command is used to apply external forces to a node, to a set of nodes or to a rigid body. If the force is
distributed to more than one node (entype = NS, G or FS), the contribution to each node is proportional to the
node mass. That is, the force applied to a node i is:
Fi =
mi
Ftot
mtot
where mtot is the total mass of all nodes in the set and Ftot is the total force.
IMPETUS Afea Solver v.3.0
133
Loads
*LOAD GRAVITY
*LOAD GRAVITY
direc, cid, addmass, csysid
Parameter deﬁni on
Variable
Description
direc
Direction for gravity loading
options: X, Y, Z
ID of a CURVE[/ref] or [ref]FUNCTION deﬁning gravity coeﬃcient versus time
Exclude added mass due to mass scaling from gravity loading
options:
0 → include added mass
1 → exclude added mass
Optional local coordinate system ID
cid
addmass
csysid
Descrip on
Deﬁnes gravity loading that acts on the full model. It is to be noted that a positive gravity constant results in
body forces acting in the negative coordinate axis direction.
IMPETUS Afea Solver v.3.0
134
Loads
*LOAD PRESSURE
*LOAD PRESSURE
entype, enid, cid, sf , tbeg , tend , csysid
Parameter deﬁni on
Variable
Description
entype
Entity type
options: P, PS, G, GS, FS
Entity identiﬁcation number
ID of a CURVE[/ref] or or [ref]FUNCTION deﬁning pressure versus time
Pressure curve scale factor
default: 1
Start time
default: 0
End time
default: 1.0e10
Optional coordinate system ID. If deﬁned, only surfaces visible from its origin are exposed
to the pressure load
default: not used
enid
cid
sf
tbeg
tend
csysid
Descrip on
Deﬁnition of pressure boundary condition.
IMPETUS Afea Solver v.3.0
135
Loads
*LOAD SHEAR
*LOAD SHEAR
entype, enid, cidτ , cidvx , cidvy , cidvz , tbeg , tend
Parameter deﬁni on
Variable
Description
entype
Entity type
options: P, PS, FS
Entity identiﬁcation number
ID of a CURVE[/ref] or [ref]FUNCTION
ID of a CURVE[/ref] or [ref]FUNCTION
ID of a CURVE[/ref] or [ref]FUNCTION
ID of a CURVE[/ref] or [ref]FUNCTION
Start time
default: 0
End time
default: 1.0e10
enid
cidτ
cidvx
cidvy
cidvz
tbeg
tend
deﬁning
deﬁning
deﬁning
deﬁning
the shear traction
reference velocity in x-direction
reference velocity in y-direction
reference velocity in z-direction
Descrip on
This command deﬁnes shear traction on a surface. It can be used to model drag forces and prescribed friction
loads. The local direction of the traction ˆt is in that of the reference velocity vref vector minus the local velocity
vector v(x), projected onto the surface.
ˆt =
ˆ⊗n
ˆ)(vref − v)
(I − n
ˆ⊗n
ˆ)(vref − v)k
k(I − n
ˆ=n
ˆ(x) is the local surface normal direction.
Here n
IMPETUS Afea Solver v.3.0
136
Loads
*LOAD THERMAL BODY
*LOAD THERMAL BODY
coid, entype, enid, cid1 , sf , tbeg , tend , cid2
Parameter deﬁni on
Variable
Description
coid
entype
Command ID
Entity type
options: P, PS, ALL
Entity identiﬁcation number
ID of a CURVE[/ref] or [ref]FUNCTION f1 deﬁning the thermal body load versus time
(power/unit volume)
Curve scale factor
default: 1
Start time
End time
default: 1.0e20
ID of an optional CURVE[/ref] or [ref]FUNCTION f2 deﬁning the total thermal body
load versus time (power)
enid
cid1
sf
tbeg
tend
cid2
Descrip on
This command is used to apply a thermal body load (power per unit volume).
f2 is an optional CURVE[/ref] or [ref]FUNCTION describing the exact total power of the heat source. It is needed
in situations where the heat source described by f1 (power/unit volume) is partially outside the body where the
energy is to be deposited. The magnitude of f1 is then scaled with a factor α in order to match the speciﬁed
total power in f2 .
∫
α
f1 (x, t)dV = f2 (t)
V
V is the body volume, x is a spatial coordinate and t is the time. Hence, the heat power per unit volume
p deposited at a location x becomes:
p = α · f1 (x, t)
IMPETUS Afea Solver v.3.0
137
Loads
*LOAD THERMAL SURFACE
*LOAD THERMAL SURFACE
coid, entype, enid, cid, sf , tbeg , tend
Parameter deﬁni on
Variable
Description
coid
entype
Command ID
Entity type
options: FS, G, GS, P, PS, ALL
Entity identiﬁcation number
ID of a CURVE[/ref] or [ref]FUNCTION deﬁning the thermal surface load versus time
(power/unit area)
Curve scale factor
default: 1
Start time
End time
default: 1.0e20
enid
cid
sf
tbeg
tend
Descrip on
This command is used to apply a thermal surface load (power per unit area).
IMPETUS Afea Solver v.3.0
138
Loads
*PRESTRESS BOLT
*PRESTRESS BOLT
pidbolt , pidnut , cid, sf , tbeg , tend
Parameter deﬁni on
Variable
Description
pidbolt
pidnut
cid
sf
Bolt part ID
Nut part ID
ID of a CURVE[/ref] or [ref]FUNCTION deﬁning bolt shaft stress versus time
Shaft stress curve scale factor
default: 1
Start time
End time
default: 1.0e20
tbeg
tend
Descrip on
This command is used to prestress a set of bolts and to apply balancing forces to the corresponding nuts. pid bolt
is assumed to contain one or several bolts. pid nut must contain the same number of nuts. The function identiﬁes
the discrete bolts and nuts and creates bolt-nut pairs. The bolt shafts are prestressed with the axial stress deﬁned
by curve cid.
IMPETUS Afea Solver v.3.0
139
Contact and ed interfaces
Contact and ed interfaces
*CONTACT
*CONTACT SUPER
*MERGE
*MERGE FAILURE COHESIVE
*MERGE FAILURE FORCE
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Contact and ed interfaces
*CONTACT
*CONTACT
coid
entypes , enids , entypem , enidm , µ, pf ac, tbeg , tend
erode, ξ, gids , gidm , δof f set , δmax , αedge , merge
ﬁdswear , ﬁdmwear , ﬁdthermal
Parameter deﬁni on
Variable
Description
coid
entypes
Contact command ID
Slave entity type
options: P, PS, ALL
Slave entity identiﬁcation number
Master entity type
options: P, PS, ALL
Master entity identiﬁcation number
Coulomb coeﬃcient of friction or FUNCTION (see example below)
options: constant, fcn
default: 0
Penalty factor
options:
= 0 → automatic calculation of stiﬀness
6= 0 → | pfac | is the contact pressure per unit penetration distance (rec. option)
Contact start time
default: 0
Contact end time
default: 1.0e10
Flag to update contact surface as elements erode or when creating new free surfaces
through node splitting
options:
0 → contact surface is not updated
1 → contact surface is updated as new free surfaces are created
2 → contact surface is updated as new free surfaces are created + each node can be in
contact with more than one face at a time
Fraction of critical damping
default: 0.05
ID of a GEOMETRY that deﬁnes a sub-space of slave nodes
default: no geometry
ID of a GEOMETRY that deﬁnes a sub-space of master faces
default: no geometry
Maxmimum penetration oﬀset for nodes that are in contact at time zero. The oﬀset is
used to prevent unwanted contact forces
default: 0
Max initial penetration that is allowed. Nodes penetrating more than δof f set + δmax are
released
default: 0
enids
entypem
enidm
µ
pf ac
tbeg
tend
erode
ξ
gids
gidm
δof f set
δmax
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Contact and ed interfaces
αedge
merge
ﬁdswear
ﬁdmwear
ﬁdthermal
Edge-to-edge contact activation angle. An edge between two faces is active in edge-toedge contact if the angle between the face normals is larger than αedge
default: 360
Flag to deactivate merged slave nodes from the contact
options:
0 → merged nodes are active
1 → merged nodes are inactive
ID of a FUNCTION deﬁning the contact wear rate of the slave surface
default: no wear calculation
ID of a FUNCTION deﬁning the contact wear rate of the master surface
default: no wear calculation
ID of a FUNCTION deﬁning the thermal contact conductivity
default: no contact heat transfer
Descrip on
Penalty based node-to-surface contact algorithm. Both (slave) nodes and (master) faces are deﬁned from parts
or part sets. The contact command ID is needed when referring to a contact force in FUNCTION. It is otherwise
optional.
It is recommended to work with a user deﬁned absolute value for the penalty stiﬀness (pf ac < 0). With this
option activated the code automatically accounts for the contact stiﬀness and reduces the time step if necessary
in order to maintain numerical stability. If mass scaling is activated (see ∆tmin in TIME) mass is added where
needed to compensate for the contact stiﬀness.
Time histories of contact forces, energies, artiﬁcially added contact interface mass and maximum contact penetration are output to the ASCII ﬁle contact.out The time history data can be visualized with IMPETUS Afea
Post Processor.
Rigid shell elements must be oriented such that the element face normals (right hand rule) point towards the
object they are to be in contact with.
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Contact and ed interfaces
*MERGE
*MERGE
entypes , enids , entypem , enidm , tol, mﬁd, gid
Parameter deﬁni on
Variable
Description
entypes
Slave entity type
options: P, PS
Slave entity identiﬁcation number
Master entity type
options: P, PS
Master entity identiﬁcation number
Tolerance for merging
default: 1% of the master face side length
ID of MERGE FAILURE command
default: no failure
ID of GEOMETRY deﬁning the region to be merged
default: no geometry
enids
entypem
enidm
tol
mﬁd
gid
Descrip on
This command can be used to merge disjointed meshes.
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Contact and ed interfaces
*MERGE FAILURE COHESIVE
*MERGE FAILURE COHESIVE
mﬁd, σf ail , τf ail , GI , GII , ∆ref
Parameter deﬁni on
Variable
Description
mﬁd
σf ail
τf ail
GI
GII
∆ref
Merge failure command ID
Tensile failure stress
Shear failure stress
Modus I energy per unit area
Modus II energy per unit area
Element reference size
Descrip on
Speciﬁes failure of a merged interface MERGE. Failure is initiated when:
(
ξσ
σf ail
)2
(
+
ξτ
τf ail
)2
≥1
where ξ is a scale factor accounting the inability to resolve stress concentrations at coarse element grids:
√
ξ = max(1, ∆/∆ref )
∆ is the local characteristic element size on the slave side of the merge interface. The stress unloading from
failure is a linear function of the crack opening distance. It is deﬁned such that the consumed energy per unit
area of cracking G is:
√(
)2 (
)2
σ
τ
GI +
GII
G=
σf ail
τf ail
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Contact and ed interfaces
*MERGE FAILURE FORCE
*MERGE FAILURE FORCE
mﬁd, Tf ail , Sf ail
Parameter deﬁni on
Variable
Description
mﬁd
Tf ail
Sf ail
Merge failure command ID
Tensile failure force
Shear failure force
Descrip on
Speciﬁes failure of a merged interface MERGE. Failure is initiated when:
(
T
Tf ail
)2
(
+
S
Sf ail
)2
≥1
where T and S is the total tensile force and shear force between the merged interfaces, respectively. Note
that compressive forces will not lead to failure.
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Rigid bodies
Rigid bodies
*RIGID
*RIGID
*RIGID
*RIGID
BODY
BODY
BODY
BODY
IMPETUS Afea Solver v.3.0
DAMPING
INERTIA
JOINT
MERGE
146
Rigid bodies
*RIGID BODY DAMPING
*RIGID BODY DAMPING
pid1 , pid2 , C, tbeg , tend
Parameter deﬁni on
Variable
Description
pid1
pid2
C
tbeg
tend
Rigid body part ID 1
Rigid body part ID 2
Damping coeﬃcient
Start time
End time
Descrip on
Applies a damping force between two rigid bodies. The force is deﬁned as:
F = C · (vpid1 − vpid2 )
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Rigid bodies
*RIGID BODY INERTIA
*RIGID BODY INERTIA
pid, m, xc , yc , zc , I11 , I22 , I33
I12 , I23 , I31
Parameter deﬁni on
Variable
Description
pid
m
xc , yc , zc
I11 , I22 , I33
I12 , I23 , I31
Rigid body part ID
Rigid body mass
Center of gravity
Moment of inertia (diagonal terms)
Moment of inertia (oﬀ-diagonal terms)
Descrip on
This command allows the user to deﬁne the mass, center of gravity and moment of intertia of a rigid body.
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Rigid bodies
*RIGID BODY JOINT
*RIGID BODY JOINT
coid
entype1 , enid1 , entype2 , enid2 , bctr , bcrot , csysid1 , csysid2
rx−, rx+, ry−, ry+, rz−, rz+, gap
cidx , cidy , cidz
Parameter deﬁni on
Variable
Description
coid
entype1
Joint ID
Entity type 1
options: P, CR
Entity identiﬁcation number 1
Entity type 2
options: P, CR
Entity identiﬁcation number 2
Constrained translational degrees of freedom
options: X, Y, Z, XY, YZ, ZX, XYZ
Constrained rotational degrees of freedom
options: X, Y, Z, XY, YZ, ZX, XYZ
ID of coordinate system deﬁning initial location of joint and orientation of Entity 1
default: global coordinates are used
ID of coordinate system deﬁning initial orientation of Entity 2
default: csysid2 = csysid1
Maximum free rotation angle around x-axis in negative direction (deg)
Maximum free rotation angle around x-axis in positive direction
Maximum free rotation angle around y-axis in negative direction
Maximum free rotation angle around y-axis in positive direction
Maximum free rotation angle around z-axis in negative direction
Maximum free rotation angle around z-axis in positive direction
Joint gap in all directions (clearance)
default: no gap
ID of CURVE describing rotational resistance (torque) as function of rotation angle
around x-axis (deg)
default: no rotational resistance
ID of CURVE describing rotational resistance (torque) as function of rotation angle
around y-axis
default: no rotational resistance
ID of CURVE curve describing rotational resistance (torque) as function of rotation angle
around z-axis
default: no rotational resistance
enid1
entype2
enid2
bctr
bcrot
csysid1
csysid2
rx−
rx+
ry−
ry+
rz−
rz+
gap
cidx
cidy
cidz
Descrip on
This command deﬁnes a joint between two rigid bodies or rigid connectors (see CONNECTOR RIGID).
The joint is initially centered at the origin of csysid1 . csysid1 also deﬁnes initial local directions in which the joint
constraints are deﬁned and forces/torques are output. csysid2 is used to deﬁne non-zero relative rotations at the
IMPETUS Afea Solver v.3.0
149
Rigid bodies
initial state. csysid2 is only needed if the free rotations are limited or if rotational resistance is deﬁned.
The joint rotation angle is deﬁned as the rotation of enid2 minus the rotation of enid1 . A non-zero initial rotation
angle can be deﬁned though csysid1 and csysid2 .
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Rigid bodies
*RIGID BODY MERGE
*RIGID BODY MERGE
setid
Parameter deﬁni on
Variable
Description
setid
Rigid body part set ID
Descrip on
This command is used to merge rigid bodies. The part with the lowest ID becomes the master. The master part
ID or title is the one being referred to in the ASCII output ﬁle rigid.out.
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Connectors
Connectors
*CONNECTOR RIGID
*CONNECTOR SPR
*CONNECTOR SPRING
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Connectors
*CONNECTOR RIGID
*CONNECTOR RIGID
coid, entype, enid
Parameter deﬁni on
Variable
Description
coid
entype
Connector ID
Entity type
options: NS, G
Entity ID
enid
Descrip on
This command adds rigid connections between a set of nodes, so that the set of nodes will behave like a rigid
body. The motion of and the forces acting on the connectors is output to the ASCII ﬁle connector rigid.out.
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Connectors
*CONNECTOR SPR
*CONNECTOR SPR
coid, pids , pidm , csysid
R, h, m, fnmax , ftmax , dmax
, dmax
, ξn
n
t
ξt , a1 , a2 , a3
Parameter deﬁni on
Variable
Description
coid
pids
pidm
csysid
R
h
m
fnmax
ftmax
dmax
n
dmax
t
ξn
ξt
a1 , a2 , a3
SPR connector ID
Slave part ID
Master part ID
Coordinate system ID deﬁning location of rivet
Rivet radius
Rivet height
Rivet mass
Pull-out strength
Shear strength
Pull out failure displacement
Shear failure displacement
Dimensionless parameter controlling the shape of the force pull-out curve
Dimensionless parameter controlling the shape of the force shear displacement curve
Parameters deﬁning the strength in directions between pure pull-out and pure shear
Descrip on
This is a point connector model that couples a group of nodes on a slave sheet with a group of nodes on a master
sheet. The members in the groups are those nodes located inside the rivet, deﬁned through location, radius and
height. At least three nodes on each side are required for a consistent transfer of forces and moments. The rivet
radius is automatically increased in case not enough nodes are located within the speciﬁed rivet geometry.
Hanssen et al. (2010) provides a detailed description of the model. A brief description follows below.
The rivet normal and shear forces are:
fn =
dn
fˆn (η max )
max
η
dmax
n
ft =
dt
fˆt (η max )
max
η
dmax
t
where dn and dt are the rivet elongations in the normal and tangential directions. η max is a damage measure that grows from 0 to 1.
{
η˙ : η = η max
max
η˙
=
0 : η < η max
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Connectors
fˆn (η max ) and fˆt (η max ) are force-displacement curves (see ﬁgure below).
Figure 26:
η is a normalized eﬀective displacement:
η = [ξ + (1 − ξ)a]
√
(dn /dmax
)2 + (dt /dmax
)2
n
t
ξ is a parameter ranging from 0 to 1 and it scales the eﬀective displacement as a function of the direction
of the displacement vector in the (dt , dn )-plane.
27
ξ =1−
4
(
2θ
π
)2
27
+
4
(
2θ
π
)3
where θ = arctan(dn /dt ). The directional scaling is allowed to change as damage evolves. This is done by
deﬁning the following relationship for the shape coeﬃcient a:
{
max
ξt −η max
a1 + η ξt a2 : η max < ξt
ξt
max
a=
1−η max
a2 + η ξt−ξt a3 : η max ≥ ξ
ξt
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Connectors
*CONNECTOR SPRING
*CONNECTOR SPRING
coid, N1 , N2 , m, k, ξ, Ff ail , direc
Parameter deﬁni on
Variable
Description
coid
N1
N2
m
k
Spring connector ID
Node 1
Node 2
Mass
Stiﬀness (force per unit distance of elongation) or a FUNCTION deﬁning the elastic force
versus elongation
Fraction of critical damping or a FUNCTION deﬁning the damping force versus elongation
rate
Spring failure force
default: No failure
Spring force direction
options:
0 → tension and compression
1 → tension only
2 → compression only
ξ
Ff ail
direc
Descrip on
This command deﬁnes a linear spring between two nodes.
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Parameters and func ons
Parameters and func ons
*CURVE
*FUNCTION
*FUNCTION STATIC
*PARAMETER
IMPETUS Afea Solver v.3.0
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Parameters and func ons
*CURVE
*CURVE
cid, sfx , sfy
x 1 , y1
.
x n , yn
Parameter deﬁni on
Variable
Description
cid
sfx
Curve identiﬁcation number
Scale factor for abscissa values
default: 1
Scale factor for ordinate values
default: 1
First abscissa ordinate pair
Last abscissa ordinate pair
sfy
x 1 , y1
x n , yn
Descrip on
Deﬁnition of a piecewise linear curve. Note that a curve and a function (see FUNCTION) can not have the same
ID.
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Parameters and func ons
*FUNCTION
*FUNCTION
ﬁd, derivative, f (0), f˙(0)
expression
Parameter deﬁni on
Variable
Description
ﬁd
derivative
Function ID
Function derivative level
options:
0 → f (., t) = expression
1 → f˙(t) = expression
2 → f¨(t) = expression
Function value at time 0 (used if derivative > 0)
First derivative of function at time 0 (used if derivative = 2)
Analytical expression
f (0)
f˙(0)
expression
Descrip on
This command can be used to deﬁne analytical functions to be used in the same way as curves (see CURVE) when
applying loads or boundary conditions. Note that a curve and a function can not have the same ID. Functions can
be deﬁned to depend on certain simulation results, for example node velocities and contact forces. A complete
listing of built in functions and parameters is given in the General section.
If derivative=1 the expression deﬁnes the ﬁrst derivative of the function (with respect to time):
∫ t
f (t) = f (0) +
(expression)dτ
0
With derivative=2 the expression deﬁnes the second derivative of the function:
]
∫ t[
∫ τ
0
˙
f (t) = f (0) +
f (0) +
(expression)dτ dτ
0
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159
Parameters and func ons
*FUNCTION STATIC
*FUNCTION STATIC
ﬁd
expression
Parameter deﬁni on
Variable
Description
ﬁd
expression
Function ID
Analytical expression
Descrip on
This command is used to deﬁne a ﬁeld at time zero. The function is evaluated at each node or integration point
during initialization. The values are accessible throughout out the simulation and are typically used to deﬁne
properties of functionally graded materials.
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Parameters and func ons
*PARAMETER
*PARAMETER
%param = expression, description
Parameter deﬁni on
Variable
Description
%param = expression
description
Parameter name and an expression deﬁning its value
Optional parameter description
Descrip on
The purpose of this command is to deﬁne parameters, that can be used inside expressions anywhere in the
command ﬁle. Brackets are used to mark the beginning and end of an expression. Parameters should always be
preceeded by the preﬁx %.
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Geometries
Geometries
*GEOMETRY
*GEOMETRY
*GEOMETRY
*GEOMETRY
*GEOMETRY
*GEOMETRY
*GEOMETRY
IMPETUS Afea Solver v.3.0
BOX
EFP
PART
PIPE
SEED COORDINATE
SEED NODE
SPHERE
162
Geometries
*GEOMETRY BOX
*GEOMETRY BOX
gid, csysid
x 1 , y1 , z 1 , x 2 , y2 , z 2
Parameter deﬁni on
Variable
Description
gid
csysid
Geometry identiﬁcation number
Local coordinate system ID
default: global coordinate system is used
Box corner coordinate 1
Box corner coordinate 2
x1 , y1 , z1
x2 , y2 , z2
Descrip on
This command is used to deﬁne a box in space, with corner coordinates at (x1 , y1 , z1 ) and (x2 , y2 , z2 ).
Figure 27: box
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Geometries
*GEOMETRY EFP
*GEOMETRY EFP
gid, csysid
x1 , y1 , z1 , x2 , y2 , z2 , R1 , R2
Parameter deﬁni on
Variable
Description
gid
csysid
Geometry identiﬁcation number
Local coordinate system ID
default: global coordinate system is used
Face center coordinate 1
Face center coordinate 2
Cylinder radius
Top face radius
x1 , y1 , z1
x2 , y2 , z2
R1
R2
Descrip on
This command is used to deﬁne the shape of a charge for an explosively formed projectile (EFP) with face center
coordinates at (x1 , y1 , z1 ) and (x2 , y2 , z2 ), radius R1 and top face radius R2 .
Figure 28: efp
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Geometries
*GEOMETRY PART
*GEOMETRY PART
gid
pid
Parameter deﬁni on
Variable
Description
gid
pid
Geometry identiﬁcation number
Part ID
Descrip on
This command is used to deﬁne a geometry with the shape of a part.
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Geometries
*GEOMETRY PIPE
*GEOMETRY PIPE
gid, csysid
x1 , y1 , z1 , x2 , y2 , z2 , R1 , R2
Parameter deﬁni on
Variable
Description
gid
csysid
Geometry identiﬁcation number
Local coordinate system ID
default: global coordinate system is used
Face center coordinate 1
Face center coordinate 2
First radius at face 1
Second radius at face 2
x1 , y1 , z1
x2 , y2 , z2
R1
R2
Descrip on
This command is used to deﬁne a straight pipe or cylinder in space, with its face center coordinates at (x1 , y1 ,
z1 ) and (x2 , y2 , z2 ). Note that the smaller of R1 and R2 is automatically taken as the inner radius.
Figure 29: pipe
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Geometries
*GEOMETRY SEED COORDINATE
*GEOMETRY SEED COORDINATE
gid
x, y, z, αc
Parameter deﬁni on
Variable
Description
gid
x
y
z
αc
Geometry identiﬁcation number
x-coordinate
y-coordinate
z-coordinate
Cut-oﬀ angle
default: 45◦
Descrip on
This command is used to deﬁne a surface from a seed coordinate. The surface propagates from the external
element face nearest the given seed coordinate. αc is the angle between two faces that deﬁnes the boundary of
the surface (default αc = 45◦ ).
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Geometries
*GEOMETRY SEED NODE
*GEOMETRY SEED NODE
gid
nid1 , nid2 , αc
Parameter deﬁni on
Variable
Description
gid
nid1 , nid2
αc
Geometry identiﬁcation number
Seed nodes
Cut-oﬀ angle
default: 45◦
Descrip on
This command is used to deﬁne a surface from seed nodes with ID nid1 and nid2 . nid2 only needs to be given
if nid1 is located on an edge (see ﬁgure below). αc is the angle between two faces that deﬁnes the boundary of
the surface (default αc = 45◦ ).
Figure 30: seed node
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Geometries
*GEOMETRY SPHERE
*GEOMETRY SPHERE
gid, csysid
x, y, z, R
Parameter deﬁni on
Variable
Description
gid
csysid
Geometry identiﬁcation number
Local coordinate system ID
default: global coordinate system is used
Sphere center coordinate
Sphere radius
x, y, z
R
Descrip on
This command is used to deﬁne a sphere in space, with its center at (x, y, z) and with radius R.
Figure 31: sphere
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Sets
Sets
*SET
*SET
*SET
*SET
*SET
ELEMENT
FACE
GEOMETRY
NODE
PART
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Sets
*SET ELEMENT
*SET ELEMENT
setid
eid1 , ..., eid8
.
eidM , ..., eidN
Parameter deﬁni on
Variable
Description
setid
eid1 , ..., eid8
eidM , ..., eidN
Unique element set identiﬁcation number
Element identiﬁcation number 1 to 8
Element identiﬁcation number M to N
Descrip on
This command deﬁnes a set of elements.
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Sets
*SET FACE
*SET FACE
setid
nid11 , nid12 , nid13 , nid14
.
nidN1 , nidN2 , nidN3 , nidN4
Parameter deﬁni on
Variable
Description
setid
nid11 , nid12
nid13 , nid14
nidN1 , nidN2
nidN3 , nidN4
Unique face set identiﬁcation number
Corner node ids of the ﬁrst face in the list
Corner node ids of the last face in the list
Descrip on
This command deﬁnes a set of faces.
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Sets
*SET GEOMETRY
*SET GEOMETRY
setid
gid1 , ..., gid8
.
gidM , ..., gidN
Parameter deﬁni on
Variable
Description
setid
gid1 , ..., gid8
gidM , ..., gidN
Unique geometry set identiﬁcation number
Geometry identiﬁcation number 1 to 8
Geometry identiﬁcation number M to N
Descrip on
This command deﬁnes a set of geometries (see e.g. GEOMETRY BOX).
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Sets
*SET NODE
*SET NODE
setid
nid1 , ..., nid8
.
nidM , ..., nidN
Parameter deﬁni on
Variable
Description
setid
nid1 , ..., nid8
nidM , ..., nidN
Unique node set identiﬁcation number
Node identiﬁcation number 1 to 8
Node identiﬁcation number M to N
Descrip on
This command deﬁnes a set of nodes.
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Sets
*SET PART
*SET PART
setid
range1 , ..., rangeK
.
rangeM , ..., rangeN
Parameter deﬁni on
Variable
Description
setid
range1 , ..., rangeK
rangeM , ..., rangeN
Unique part set identiﬁcation number
Part ID range 1 to K
Part ID range M to N
Descrip on
This command deﬁnes a set of parts. A range is either a part ID (e.g. 10), or a range of parts (e.g. 10..20).
IMPETUS Afea Solver v.3.0
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Coordinate system
Coordinate system
*COORDINATE SYSTEM CYLINDRICAL
*COORDINATE SYSTEM FIXED
*COORDINATE SYSTEM NODE
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Coordinate system
*COORDINATE SYSTEM CYLINDRICAL
*COORDINATE SYSTEM CYLINDRICAL
csysid, x0 , y0 , z0
ˆ 0x , R
ˆ 0y , R
ˆ 0z
zˆx , zˆy , zˆz , R
Parameter deﬁni on
Variable
Description
csysid
x0
y0
z0
zˆx
zˆy
zˆz
ˆ 0x
R
ˆ 0y
R
ˆ 0z
R
Unique identiﬁcation number
X-coordinate of a point on the cylinder axis
Y-coordinate of a point on the cylinder axis
Z-coordinate of a point on the cylinder axis
X-component of axial direction
Y-component of axial direction
Z-component of axial direction
X-component of radial direction at θ = 0
Y-component of radial direction at θ = 0
Z-component of radial direction at θ = 0
Descrip on
Deﬁnes a ﬁxed local cylindrical coordinate system. A point on the cylindrical center axis is located at (x0 , y0 ,
x0 ) and the local axial direction is (ˆ
zx , zˆy , zˆz ).
Figure 32: Cylindrical coordinate system
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Coordinate system
*COORDINATE SYSTEM FIXED
*COORDINATE SYSTEM FIXED
csysid, x0 , y0 , z0
x
ˆx , x
ˆy , x
ˆz , y¯x , y¯y , y¯z
Parameter deﬁni on
Variable
Description
csysid
x0 , y0 , z0
x
ˆx , x
ˆy , x
ˆz
y¯x , y¯y , y¯z
Unique identiﬁcation number
Coordinate of origin
Direction of local x-axis
Vector needed for the deﬁnition of the local y- and z-axis
Descrip on
Deﬁnes a ﬁxed local cartesian coordinate system. The system is deﬁned through the input of direction cosines.
The origin is located at (x0 , y0 , z0 ) and the local x-direction is (ˆ
xx , x
ˆy , x
ˆz ). The local z-direction is deﬁned as
ˆz = ˆx × ¯y/|ˆx × ¯y| and the local y-direction as ˆy = ˆz × ˆx.
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Coordinate system
*COORDINATE SYSTEM NODE
*COORDINATE SYSTEM NODE
csysid, N1 , N2 , N3
Parameter deﬁni on
Variable
Description
csysid
N1 , N 2 , N 3
Unique identiﬁcation number
Nodes deﬁning the location and direction of the local system
Descrip on
Deﬁnes a local cartesian coordinate system. The system is deﬁned through 3 user deﬁned nodes. This system
will automatically be updated if the nodes are moving. The local x-direction, ˆx, is deﬁned as the direction of a
vector pointing from node N1 to N2 . The local z-direction, ˆz is deﬁned as the cross product of ˆx and the vector
pointing from N1 to N3 . The local y-direction is ˆy = ˆz × ˆx.
Figure 33: Coordinate system deﬁned by three nodes
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Discrete Par cles
Discrete Par cles
*PBLAST
*PBLAST AIR
*PSOIL
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Discrete Par cles
*PBLAST
*PBLAST
entype, enid, air, soil, he, Np
bcx0 , bcx1 , bcy0 , bcy1 , bcz0 , bcz1 , µ
gidglob , gidsoil , gidhe , x0 , y0 , z0 , t0 , tend
pack, ρs , ks , µs , ξs
ρhe , ehe , γhe , vhe , Dhe
Parameter deﬁni on
Variable
Description
entype
Structure entity type for particle structure interaction
options: P, PS, ALL
Structure entity ID
Air activation ﬂag
options:
0 → air is not included
1 → air is included
Soil type
options: 0 (no soil), dry, wet, user
High explosive type
options: 0 (no HE), tnt, c4, petn, m46, user
Total number of particles
Boundary conditions for global domain xmin
options:
0 → free
1 → rigid reﬂecting boundary
Boundary condition for global domain xmax
Boundary condition for global domain ymin
Boundary condition for global domain ymax
Boundary condition for global domain zmin
Boundary condition for global domain zmax
Soil-structure contact coeﬃcient of friction
ID of a GEOMETRY deﬁning the global domain
ID of a GEOMETRY deﬁning the soil domain
ID of a GEOMETRY deﬁning the high explosives domain
Detonation point
Detonation time
Particle deactivation end time
Soil packing scheme (this line is only used if soil=user)
options:
1 → dry soil (unit cell with 1k particles)
2 → wet soil (1k)
3 → dry soil (10k)
4 → wet soil (10k)
Soil density
Soil-soil contact stiﬀness
enid
air
soil
he
Np
bcx0
bcx1
bcy0
bcy1
bcz0
bcz1
µ
gidglob
gidsoil
gidhe
x0 , y0 , z0
t0
tend
pack
ρs
ks
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Discrete Par cles
µs
ξs
ρhe
ehe
γhe
vhe
Dhe
Soil-soil contact coeﬃcient of friction
Soil-soil damping coeﬃcient
HE density (this line is only used if type he=user)
HE energy per unit volume
HE fraction between Cp and Cv
HE co-volume at density=ρHE
HE detonation velocity
Descrip on
This command deﬁnes the blast loading of an FE-structure with air, soil and high explosive. Note that this command requires a unit system to be speciﬁed (see UNIT SYSTEM). Borvik et al. (2011) provides a comprehensive
description of the discrete particle method and of the used input parameters.
Note that reﬂective boundary conditions will be applied to global domain boundaries that coincide with a
BC SYMMETRY deﬁnition.
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Discrete Par cles
*PSOIL
*PSOIL
entype, enid, gidglob , gidsoil , soil, Np , µ, tend
bcx0 , bcx1 , bcy0 , bcy1 , bcz0 , bcz1
, pack, ρs , ks , µs , ξs
Parameter deﬁni on
Variable
Description
entype
Structure entity type for particle structure interaction
options: P, PS, ALL
Structure entity ID
ID of a GEOMETRY deﬁning the global domain
ID of a GEOMETRY deﬁning the soil domain
Soil type
options: dry, wet, user
Total number of particles
Soil-structure contact coeﬃcient of friction
Particle deactivation end time
Boundary conditions for global domain xmin
options:
0 → free
1 → rigid reﬂecting boundary
Boundary condition for global domain xmax
Boundary condition for global domain ymin
Boundary condition for global domain ymax
Boundary condition for global domain zmin
Boundary condition for global domain zmax
Soil packing scheme (this line is only used if soil=user)
options:
1 → dry soil (unit cell with 1k particles)
2 → wet soil (1k)
3 → dry soil (10k)
4 → wet soil (10k)
Soil density
Soil-soil contact stiﬀness
Soil-soil contact coeﬃcient of friction
Soil-soil damping coeﬃcient
enid
gidglob
gidsoil
soil
Np
µ
tend
bcx0
bcx1
bcy0
bcy1
bcz0
bcz1
pack
ρs
ks
µs
ξs
Descrip on
This command deﬁnes a domain ﬁlled with discrete particles representing sand or soil.
Note that reﬂective boundary conditions will be applied to global domain boundaries that coincide with a
BC SYMMETRY deﬁnition.
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Smoothed Par cle Hydrodynamics
Smoothed Par cle Hydrodynamics
*SPH FLUID
*SPH SENSOR PRESSURE
*SPH WATER ENTRY LAB
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Smoothed Par cle Hydrodynamics
*SPH FLUID
*SPH FLUID
entype, enid, form, vmax , giddel , ∆tc
pid1 , gid1 , dx1 , dy1 , dz1 , α1 , β1
.
pidn , gidn , dxn , dyn , dzn , αn , βn
Parameter deﬁni on
Variable
Description
entype
Structure entity type for SPH-structure interaction
options: P, PS
Structure entity ID
Formulation type
options:
1 → ﬂuid (default)
2 → gas and ﬂuid
3 → Godunov (no artiﬁcial viscosity)
4 → renormalized
101 → symplectic ﬂuid
Maximum SPH node velocity
Geometry deﬁning a bounding box for SPH node deletion
SPH contact time step size
Part ID
Geometry ID that deﬁnes a region is space that will be ﬁlled with SPH nodes
Node spacing in x-direction
Node spacing in y-direction
default: dy1 = dx1
Node spacing in z-direction
default: dz1 = dx1
Linear artiﬁcial viscosity term
default: 0.1
Quadratic artiﬁcial viscosity term
default: 0.5
Part ID
Geometry ID that deﬁnes a region is space that will be ﬁlled with SPH nodes
Node spacing in x-direction
Node spacing in y-direction
default: dyn = dxn
Node spacing in z-direction
default: dzn = dxn
Linear artiﬁcial viscosity term
default: 0.1
Quadratic artiﬁcial viscosity term
default: 0.5
enid
form
vmax
giddel
∆tc
pid1
gid1
dx1
dy1
dz1
α1
β1
pidn
gidn
dxn
dyn
dzn
αn
βn
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Smoothed Par cle Hydrodynamics
Descrip on
Deﬁnes SPH ﬂuid geometries/grids and interaction between SPH nodes and structure.
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Smoothed Par cle Hydrodynamics
*SPH SENSOR PRESSURE
*SPH SENSOR PRESSURE
sid, gid
Parameter deﬁni on
Variable
Description
sid
gid
Sensor ID
Geometry deﬁning the location of the sensor
Descrip on
Deﬁnes a sensor for pressure sampling. The pressure is output to the ASCII ﬁle sph sensor pressure.out. The
pressure is calculated as the average pressure of all SPH particles inside the geometry with ID gid.
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Smoothed Par cle Hydrodynamics
*SPH WATER ENTRY LAB
*SPH WATER ENTRY LAB
entype, enid, L, W , D, Np , vmax
bcx0 , bcx1 , bcy0 , bcy1 , bcz0
Parameter deﬁni on
Variable
Description
entype
Structure entity type for SPH-structure interaction
options: P, PS
Structure entity ID
Length of water domain (x-direction)
Width of water domain (y-direction)
default: 0 (2D formulation)
Depth of water domain (z-direction)
Number of SPH particles
Maximum expected water velocity
Boundary conditions for water domain xmin
options:
0 → reﬂective
1 → absorbing
2 → free
Boundary condition for water domain xmax
Boundary condition for water domain ymin
Boundary condition for water domain ymax
Boundary condition for water domain zmin
enid
L
W
D
Np
vmax
bcx0
bcx1
bcy0
bcy1
bcz0
Descrip on
Deﬁnes a basin of water modeled with SPH. The command currently only supports SI-units. The command
UNIT SYSTEM needs to be deﬁned. The neutral water level is always at z = 0.
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