Summary of Thermo-mechanical
analyses of the HOM couplers
Carlo Zanoni EN-MME-EDM
Goal
HOM no bellow
Comparison
(same mesh and defeaturing)
- Stress
- Deformation
H HOM
V HOM
Materials properties
Stainless Steel
316LN
Poisson’s ratio [1]
0.38
0.27
Elastic modulus (GPa) [1]
103
196
Yield strength Rp0.2 (MPa)
75
280
Properties
Integrated thermal contraction
1.43∙10−3
3∙10−3
4.91∙10−6
1.03∙10−5
Yield strength Rp0.2 (MPa) [3]
480÷520
850÷1050
Max allowable stress Rp0.2/1.5
320÷347
567÷700
293 K
Niobium
2K
Material
Δ𝐿
𝐿 𝑅𝑇→4𝐾
Coefficient of thermal contraction
[2]
Δ𝐿
Δ𝑇𝐿 𝑅𝑇→4𝐾
(1/K)
[1] D. Vaucoret, Materials and Ansys Library for Design Office, EDMS 1291793.
[2] H. Kaiser, Ge. Meyer, H.B. Peters, and G. Weichert, “Helium Vessel for the TTF Cavity,” TESLA Collaboration Report 94–26,
October 1994.
3
[3] Information provided by Ignacio.
Loads (nominal)
• Temperature (22 C to -271.15 C)
• Pressure: 0.18 Mpa
• HOM line load: 20 N at 500 mm
• Boundary:
• Remote displacement of the bolts of the
horizontal flange
• Δ gap: Temperature contraction
• Max stress: temperature and pressure
• Modes: Temperature contraction
No bellows
No bellows (HOM line + pressure)
Horizontal Bellow
Horizontal Bellow (HOM line + pressure)
Radial Bellow
Radial Bellow (HOM line + pressure)
Deformation (contraction + HOM line load)
Direction of hook movement
changes with different designs
Deformation
1st Mode: 92 Hz
Nb tube from
plate
No Bellows
Δ gap
Nb tube from
bulk
0.11 mm
0.08 mm
240 MPa
150 MPa/150 MPa
(nominal)
Max Stress
(nominal/5 kg HOM line)
1st Mode
Horizontal Bellow
Δ gap
92 Hz
0.1 mm
0.08 mm
54 MPa
32 MPa/54 MPa
(nominal)
Max Stress
(nominal/5 kg HOM line)
1st Mode
Radial Bellow
Δ gap
92 Hz
0.1 mm
0.07 mm
66 MPa
38 MPa/50 MPa
(nominal)
Max Stress
(nominal/5 kg HOM line)
1st Mode
92 Hz