1. LEB 14 X 11 C. Garion Aluminum bellows for LHC experiments C. Garion, TE/VSC

2. LEB 14 X 11 Outline C. Garion Material requirements & choice Design EJMA and Manufacturing requirements Mechanical bellows properties Manufacturing process Tests Status and next steps Conclusion

3. LEB 14 X 11 C. Garion Material Requirements: Formability (high ductility) Weldability (also with 2219) Low Heat affected zone Available in thin foils Good mechanical properties at elevated temperatures (>180  C) 5083 H111, 0.2 and 0.3mm thick, 200 mm width Weld reliability

4. LEB 14 X 11 C. Garion Design Algorithm of optimization of bellows expansion joints (Based on EJMA) Minimise the objective function: inequality constraints: bellows convoluted length inner diameter outer diameter bellows maxi compression membrane stress membrane & bending stress fatigue life column buckling in-plane squirm Atlas constraints (technical specification EDMS 429891): Lb max = 100 mm D min ~ 60 mm D max = 80 mm Stroke = -24/+8mm Nf > 500 cycles

5. LEB 14 X 11 C. Garion Design Manufacturing requirements Plastic strain during forming process  Forming at elevated temperature required

6. LEB 14 X 11 C. Garion Design  13 convolutions, bellows length: ~96mm, Inner diameter: 60 mm, outer diameter: 80 mm

7. LEB 14 X 11 C. Garion Design Bellows properties – FE model Force/displacement curve Elastic-plastic buckling analysis Plastic and total strain fields + Manson Coffin equation:  Fatigue life estimation FE model

8. LEB 14 X 11 C. Garion Bellows manufacturing process (courtesy of L. Prever Loiri, EN/MME) Aluminum foil Rolled tube & longitudinal weld (EB) Welds of the end fittings (EB) Forming @242°C combining pressure and displacement loading Cut of the end fittings Cleaning with phosphor nitric acid [VSC/SCC]  Optimization of the temperature distribution  Automatic displacement Leak test after “bake out”

9. LEB 14 X 11 C. Garion Bellows manufacturing process Some Pictures (EN/MME) Tubes equipped with the end fittings Tubes and pressure system Die system Forming system

10. LEB 14 X 11 Tests (courtesy of H. Rambeau) C. Garion Fatigue tests PrototypeSeries 1Series 2 RT =2300 =19503019 150  C =1000 200  C 1185 250  C 193 All bellows with welding defects Collapse of the convolutions @ 250  C

11. LEB 14 X 11 C. Garion Status and next steps ATLAS (VA chamber): Bellows manufactured Fatigue life qualification done and will be continued Tests on NEG coating ongoing LHCb: Z=2800, same bellows as ATLAS VA, design of compensator to be redone UX85-2/3: design done (limitation by the sheet width) forming tooling being manufactured/assembled first tubes done CMS (End cap pipe compensator): Under consideration

12. LEB 14 X 11 C. Garion Conclusion Design and manufacturing of aluminum bellows are mastered. Aluminum bellows are suitable and have been qualified for UHV applications. Bellows are qualified for a temperature of 200  C. Bellows for ATLAS VA chamber are ready for installation (after leak test). Manufacturing of the bellows for LHCb are in progress.

13. LEB 14 X 11 C. Garion RT 150  C 200  C250  C Tensile curves 0.3 mm, RD

14. LEB 14 X 11 C. Garion S-N curve Fatigue of deep rolled AlMg4.5Mn (AA5083) in the temperature range 20–300 ◦C, P. Juijerm et al., Materials Science and Engineering A 379 (2004) 286–292