MQXF support structure
An extension of LARP experience
Helene Felice
MQXF Design Review
December 10th to 12th , 2014
CERN
Snapshot of LARP support structure
experience
Length
2004
0.3 m
1m
3.6-3.7 m
2005
SQ
2006 Subscale quad
2007
2008
LR
Long Racetrack
TQ
Technology Quadrupole
LRS01-02
TQS01/02a-b-c/03a-b-c-d
2009
LQ
Long
Quadrupole
2010
2011
2012
HQ
High-field
Quadrupole
LQS01a-b/02/03
HQ01a-b-c-d-e
HQ02a-b / HQ03a
2013
2014
Time
Helene Felice
12/10/2014
2
Step-by-step technology demonstration
Length
2004
0.3 m
1m
3.6-3.7 m
2005
SQ
2006 Subscale quad
Concept
2007
2008
TQ
Technology Quadrupole
2009
TQS01/02a-b-c/03a-b-c-d
Concept on cos2q
Technology selection
LR
Long Racetrack
LRS01-02
Length demonstration
Scale-up & design optimization
2010
2011
2012
2013
HQ
High-field
Quadrupole
LQ
Long
Quadrupole
LQS01a-b/02/03
Some accelerator quality features
Length with cos2q
Accommodating variability in coil
dimension
HQ01a-b-c-d-e
HQ02a-b / HQ03a
Accelerator quality features
Mechanical alignment
2014
Time
Helene Felice
12/10/2014
3
Exploration of the stress limits
Length
2004
0.3 m
1m
3.6-3.7 m
2005
SQ
2006 Subscale quad
Concept
2007
LR
Long Racetrack
2008
TQ
Technology Quadrupole
2009
TQS01/02a-b-c/03a-b-c-d
Concept on cos2q
Scale-up & design optimization
Technology selection
Ultimate stress exploration
2010
2011
2012
2013
2014
HQ
High-field
Quadrupole
LRS01-02
Length demonstration
LQ
Long
Quadrupole
LQS01a-b/02/03
Some accelerator quality features
Length with cos2q
Accommodating variability in coil
dimension
HQ01a-b-c-d-e
HQ02a-b / HQ03a
Accelerator quality features
Mechanical alignment
High stress regime
Time
Helene Felice
12/10/2014
4
Outline
• Shell-based support structure concept
• Exploring the limits
– TQ high stress
• Step-by-step technology demonstration
– Design optimization
– Length
• QXF support structure
– Main features
Helene Felice
12/10/2014
5
Shell-based support structure
Motivation and concept
• Shell-based support structure often referred as
“bladder and keys” structure
developed at LBNL for strain sensitive material
coil
pad
shell
Helene Felice
12/10/2014
6
Shell-based support structure
Supporting tools
• Numerical tools
• Instrumentation
•
•
•
Helene Felice
Assembly based on analysis
Control of the pre-stress
level
Constant feedback between
SG measurements and
model
12/10/2014
7
Shell-based support structure
Concept
• Shell-based support structure often referred as
“bladder and keys” structure
developed at LBNL for strain sensitive material
Helene Felice
12/10/2014
8
Shell-based support structure
Concept
Inflated Bladders
• Shell-based support structure often referred as
“bladder and keys” structure
developed at LBNL for strain sensitive material
Bladder
Displacement scaling 30
Helene Felice
12/10/2014
9
Shell-based support structure
Concept Shimming of the load leys
• Shell-based support structure often referred as
“bladder and keys” structure
developed at LBNL for strain sensitive material
Bladder
Keys
Displacement scaling 30
Helene Felice
12/10/2014
10
Shell-based support structure
Concept
Cool-down
• Shell-based support structure often referred as
“bladder and keys” structure
developed at LBNL for strain sensitive material
Cool-down
Bladder
Keys
Displacement scaling 30
Helene Felice
12/10/2014
11
Shell-based support structure
Concept
Energized
• Shell-based support structure often referred as
“bladder and keys” structure
developed at LBNL for strain sensitive material
With shell structure
cold
Cool-down
Lorentz
forces
Bladder
Room
temperature
Keys
Support structure allowing
fine tuning of the
Collaring
processDisplacement
scaling
30 Courtesy of Paolo Ferracin
Helene Felice
12/10/2014
12
Shell-based support structure
Key features
• Gradual application of the preload: no overshoot
• Tunable preload
– During assembly
– In between tests
• Reversible assembly process
– Allowing replacement of a defective coil if needed
• Correlation between models and strain gauges
measurements
Helene Felice
12/10/2014
13
Outline
• Shell-based support structure concept
• Exploring the limits
– TQ high stress
• Step-by-step technology demonstration
– Design optimization
– Length
• QXF support structure
– Main features
Helene Felice
12/10/2014
14
Stress limits: defining an acceptable range
TQS03 program
CONDUCTOR
• OST RRP 108/127 strand
• High RRR
• 54 % Cu fraction
• Jc (12T, 4.3 K) 2770 A/mm2
• 27 strands cable
• 1.26 mm mid-thickness bare
• 10 mm width bare
• 0.125 mm insulation
TQS03
parameters
4.3 K
1.9 K
13.2
14.5
Bpeak ss (T)
12
13
Gss (T/m)
234
254
Iss (kA)
4 tests: TQS03 a, b, c and d
• performed with variable pre-stress
• TQS03a: 120 MPa
• TQS03b: 160 MPa
• TQS03c : 200 Mpa
• TQS03d: 120 MPa
• supported by ANSYS analysis
Helene Felice
12/10/2014
15
TQS03a
300K
4.2 K
TQS03b
300K
4.2 K
TQS03c
300K
4.2 K
TQS03d
300K
Strain gauges
location
4.2 K
3000
200MPa
2500
2000
180MPa
160MPa
160MPa
shell T meas
eq (me)
1500
Pole T meas
1000
In boxes: sig theta
measured
shell T ANSYS
Pole T ANSYS
500
Add predicted on
box
0
-110 MPa
-160 MPa
-500
-1000
-1500
-120 MPa
Good agreement
between
measurements and
ANSYS prediction
-190 MPa
Helene Felice
12/10/2014
16
100
98
96
Fraction of Iss (%)
94
92
TQS03a
93 % ~ 12.3 / 13.5 kA
90
TQS03b
91 % ~ 12 / 13.2 kA
TQS03c
88 % ~ 11.6 / 12.8 kA
TQS03d
88 %
88
86
84
82
80
78
4.3 K
1.9 K
4.3 K
• Only 5 % degradation from TQS03a to TQS03c
• TQS03d did not recover => Permanent
degradation
Helene Felice
12/10/2014
17
Strain gauge data during excitation
TQS03a
TQS03b
Preload
increase
Preload
increase
TQS03c
Strain
gauge
• conclusion
Correlation between preload levels and magnet performance allowed the
definition of a safe range of transverse stress in Nb3Sn coils
Helene Felice
12/10/2014
18
Outline
• Shell-based support structure concept
• Exploring the limits
– TQ high stress
• Step-by-step technology demonstration
– Design optimization
– Length
• QXF support structure
– Main features
Helene Felice
12/10/2014
19
From TQ to HQ
Design optimization
TQ
LQ
Plot of stress
along the
length
• No alignment
features
• Optimization of the design
• load key positon
• Pad extremity in
stainless steel to
lower peak field in the
end
• Implementation of
alignment features from
pad to shell
Helene Felice
12/10/2014
20
From TQ to HQ
Design optimization: key position optimization
TQ
- 90 mm aperture
- 12 T peak field
- 240 T/m
LQ
- 90 mm aperture
- 12 T peak field
- 240 T/m
- Fq Layer 1 = -1.5 MN/m
- Fq Layer 2 = -1.02 MN/m
- Fq Layer 1 = -1.5 MN/m
- Fq Layer 2 = -1.02 MN/m
20 MPa
-100 MPa
20 MPa
-85 MPa
Key
optimization
-187 MPa
-171 MPa
=> Optimization of the key position to improve stress distribution
Helene Felice
12/10/2014
21
From TQ to HQ
Design optimization
TQ
• No alignment
features
LQ
• Optimization of the design
• load key positon
• Pad extremity in
stainless steel to
lower peak field in the
end
• Implementation of
alignment features from
pad to shell
Helene Felice
HQ
• Cross-section
optimization
considering force
distribution between
layers
• Alignment features
between coil and
pads: aluminum
collars and key
12/10/2014
22
From TQ to HQ
Design optimization: key position optimization
TQ
- 90 mm aperture
- 12 T peak field at 4.3 K
- 240 T/m
LQ
- 90 mm aperture
- 12 T peak field at 4.3 K
- 240 T/m
HQ
- 120 mm aperture
- 14 T peak field at 4.3 K
- 200 T/m
- Fq Layer 1 = -1.5 MN/m
- Fq Layer 2 = -1.02 MN/m
- Fq Layer 1 = -1.5 MN/m
- Fq Layer 2 = -1.02 MN/m
- Fq Layer 1 = - 2.1 MN/m
- Fq Layer 2 = - 2.6 MN/m
20 MPa
-100 MPa
20 MPa
-85 MPa
MPa
MPa
-187 MPa
Key
Xsection
optimization
optimization
-171 MPa
MPa
=> Improvement of the cross-section to avoid layer 2 overloading
Helene Felice
12/10/2014
23
Helene Felice
12/10/2014
24
Stress in HQ
Adresses:
- Stress distribution
- 2D and 3D
- Pad ss and iron
- Ground for MQXF stress level
Helene Felice
12/10/2014
25
Outline
• Shell-based support structure concept
• Exploring the limits
– TQ high stress
• Step-by-step technology demonstration
– Design Optimization
– Length
• QXF support structure
– Main features
Helene Felice
12/10/2014
26
1st long shell based structure:
the Long Racetrack LR
• LRS01: full length shell
Magnet parameters
•
•
•
q 
E
(1  )
2
Friction limits the shell contractions
• Central part locked
Strain at 4.5 K consistent with 0.2 friction
model results
During excitation e.m. forces induced
slippage
(e q e z )
Helene Felice
12/10/2014
27
Impact of shell segmentation
• LRS01
– High meas. axial strain meas.
– Effect on azimuthal stress
E
(e q e z )
q 
2
1 
(
LRS
)
• LRS02 (with segmented shell)
– Reduced axial strain
LQS
LRS02
LRS01
Helene Felice
12/10/2014
#28
Length demonstration on a cos2q magnet:
the Long Quad LQ
•
•
•
•
90 mm aperture coils with Ti poles
Iron pads, masters, yokes, Al shell
Pre-load with bladders and keys
TQ coil scale-up
•
LQS01-2 Short-sample limits (4.5 K – 1.9 K)
– Gss: 240 T/m – 267 T/m
– Iss: 13.8 kA – 15.4 kA
– Peak field: 12.3 T - 13.6 T
LQS03 Short sample limit
– -Gss: 227 T/m – 250 T/m
– Iss: 12.9 kA – 14.4 kA
– Peak field: 11.5 T - 12.8 T
•
•
•
End support: plate and rods
Magnet/coil length: 3.7/3.4 m
Helene Felice
12/10/2014
29
Mechanical Analysis
Typical Stress distribution
Pole
q (MPa)
Preload for 240 T/m: 471 kN
z and ez at 300 K
- target (3D): +88 Mpa (178 kN)
+455 me
z and ez at 4.3 K
- target (3D): + 239 MPa
+ 1138 me
Preload for 260 T/m
q and eq at 300 K
- target (3D): -82 MPa
-580 me
q and eq at 4.3 K
- target (3D): -157 MPa
-1031 me
149
156
163
170
177
184
191
198
208
212
q (MPa)
-198
-180
-162
-143
-125
-107
-88
-70
-51
-33
70
60
End contact pressure (MPa)
Preload for 260 T/m
q and eq at 300 K
- target (3D): + 56 MPa
+ 750 me
q and eq at 4.3 K
- target (3D): + 183 MPa
+2080 me
Rod
End Contact
pressure (Mpa)
Shell
50
40
30
20
NO gap
10
0
293 K
-0.2
0
0.2
0.4
0.6
0.8
1
Fem/Fem_240T/m
Helene Felice
12/10/2014
30
Axial strain in shell
Helene Felice
12/10/2014
31
Production readiness:
Accommodating coil size variation
shell Strain
Gauge
measured
Expected
coil Strain
Gauge
92 % at 4.5 K
LQS01b
Pole
Strain
Gauge
LQS01a
LQS01a
pad
Nominal
Oversized
Helene Felice
12/10/2014
32
Outline
• Shell-based support structure concept
• Exploring the limits
– TQ high stress
• Step-by-step technology demonstration
– Alignment features
– Length
• QXF support structure
– Main features
Helene Felice
12/10/2014
33
From LARP to MQXF
Helene Felice
12/10/2014
34
MQXF support structure overview
• Show how the key features described before are found in
MQXF support structure design
• Point to Mariusz’s talk
Helene Felice
12/10/2014
35