1. Adam Carreon July 19, 2012 Technical Division SRF Department Dressed SSR1 Cavities

2. SSR1 cryomodule development for PXIEPage 2 Assignments 1.Engineering Note Learn the SSR1 resonator’s components and their purpose (specifically helium pressure vessel) Read and understand ASME Boiler and Pressure Vessel Code, Division 2: Design-By-Analysis Create main body of Note from failure modes in ASME Code Understand and discuss material properties, system properties, CAD models, and other specifications to fill Note Help perform analyses of failure modes and report results in Note 2.Tuner Support Arms Understand how the tuner of a cavity works Understand the support arms purpose in the tuner system Get requirements for the support arms to begin theoretical design Perform analyses on support arms in several phases

3. SSR1 cryomodule development for PXIEPage 3 Description of SSR1 Resonator Helium Vessel - The helium vessel is the outermost vessel of the SSR1 resonator and is constructed from stainless steel 316L. The SSR1 helium vessel will be designed to withhold liquid helium at a temperature of 2 K. The helium vessel's sensitivity to helium pressure fluctuations has been minimized and also reduced further by the addition of the transition ring. The helium vessel also provides two platforms which hold the tuning system is place.

4. SSR1 cryomodule development for PXIEPage 4 Description of SSR1 Resonator Superconducting Cavity - The inner vessel of the SSR1 resonator is a superconducting cavity. Most of the cavity is machined from niobium. The several locations on this cavity that are SS316L include the connecting pipes at the beam pipes, vacuum port, and power coupler locations.

5. SSR1 cryomodule development for PXIEPage 5 ASME Boiler and Pressure Vessel Code In the Code's Section VIII, Div. 2, Part 5, one can find detailed design procedures that make use of the results from the stress analysis to test the system for plastic collapse, local failure, buckling, and cyclic loading. Plastic Collapse - The analysis for this failure mode focuses on the internal pressure of the vessel and prevents plastic instability, ensuring that the pressure vessel does not experience plastic deformation that may lead to collapse. Also, the analysis avoids unbound displacement in each cross-section of the SSR1 resonator. Local Failure - The analysis for this failure mode focuses on the local strain limit for locations that have high stress values. It is a procedure to check and verify all the details of the SSR1 resonator (i.e. joints). This analysis ensures that the pressure vessel does not experience fracturing under the designed loads. Buckling - The analysis for this failure mode focuses on the compressive stress of the vessel. The failure is characterized by a sudden failure of a structural component subjected to a high compressive stress. A point of failure will occur where the actual compressive stress is greater than the ultimate compressive stress the material can withstand. Cyclic Loading - The analysis for this failure mode focuses on vessel components that experience a cyclic operation. The purpose of this analysis is to make an evaluation for fatigue based on the number of cycles the vessel will experience.

6. SSR1 cryomodule development for PXIEPage 6 Applied Loads P – Pressure in the helium space under the fault condition P S – Static head from liquid helium (considered as negligible) D – Dead weight of the vessel system T 1 – Applied tuner load of 7500 N T 2 – Cooldown from 293 K to 2 K

7. SSR1 cryomodule development for PXIEPage 7 Protection Against Plastic Collapse – GC 1 Model Material - The material model used for this analysis contained elastic-plastic material properties at 293 K. Loads - The load combination in this analysis was the following: 2.4(P+D) 1.Ramped Dead weight of the system (D) 2.Constant Dead weight of the system (D) plus ramped pressure (P) [(8 bar)] To evaluate the MAWP of the system, the last convergent solution before the collapse must be taken from the analysis result and divided by the given Load Combination Factor. Results – The time of last solution evaluated was 1.848s. This gives a MAWP at RT of: MAWP RT = (8*0.848)/2.4 = 6.79/2.4 = 2.83 bar

8. SSR1 cryomodule development for PXIEPage 8 Protection Against Plastic Collapse – GC 2 Model – GC 2: RT Material - The material model used for this analysis contained elastic- plastic material properties at 293 K. Loads - The load combination in this analysis was the following: 2.1(P+D+T 1 ) 1.Ramped Dead weight of the system (D) plus ramped Tuner system forces (T 1 ) 2.Constant Dead weight of the system (D) plus ramped pressure (P) [(8 bar)] Results – The time of last solution evaluated was 1.731s. This gives a MAWP at RT of: MAWP RT = (8*0.731)/2.1 = 5.85/2.1 = 2.78 bar Model – GC 2: CT Material - The material model used for this analysis contained elastic- plastic material properties at 2 K. Loads - The load combination in this analysis was the following: 2.1(P+D+T 1 +T 2 ) 1.Ramped Dead weight of the system (D) plus ramped Thermal cooldown (T 2 ) 2.Constant Dead weight of the system (D) plus ramped pressure (P) [(20 bar)] Results – The time of last solution evaluated was 1.94226s. This gives a MAWP at CT of: MAWP CT = (20*0.94226)/2.1 = 18.8/2.1 = 8.97 bar

9. SSR1 cryomodule development for PXIEPage 9 Protection Against Collapse from Buckling – Type 1: RT Model Material - The material model used for this analysis contained elastic-plastic material properties at 293 K. Loads - The load combination in this analysis was the following: (P+D) P = Helium Pressure [MAWP RT (2 bar)] D = Dead Weight of the System To evaluate the MAWP of the system, the lowest pressure at which buckling occurs must be taken from the analysis result and divided by the given Load Combination Factor. Cylinders under external pressure Results - Buckling occurred at a pressure of 33.09 bar MAWP RT = 33.09/2.5 = 13.24 bar

10. SSR1 cryomodule development for PXIEPage 10 Protection Against Collapse from Buckling – Type 1: CT Model Material - The material model used for this analysis contained elastic-plastic material properties at 2 K. Loads - The load combination in this analysis was the following: (P+D+T 2 ) 1.Ramped Dead weight of the system (D) plus ramped Thermal cooldown to 2 K (T 2 ) 2.Constant Dead weight of the system (D) plus ramped Pressure (P) [MAWP CT (4 bar)] Results - Buckling occurred at a pressure of 27.93 bar MAWP CT = 27.93/2.5 = 11.17 bar

11. SSR1 cryomodule development for PXIEPage 11 Protection Against Local Failure – RT: NO Tuner/Tuner Model Material - The material model used for this analysis contained elastic plastic material properties at 293 K. Loads - The load combination in this analysis was the following: (P+D) P = 2 bar (Helium Pressure) which is the target value for MAWP RT D = (mass of system)(gravity) With Tuner Loads become - (P+D+T 1 ) T 1 = 7500 N

12. SSR1 cryomodule development for PXIEPage 12 Room Temperature: NO Tuner Results

13. SSR1 cryomodule development for PXIEPage 13 Room Temperature: Tuner Results

14. SSR1 cryomodule development for PXIEPage 14 Protection Against Local Failure – CT: NO Tuner/Tuner Model Material - The material model used for this analysis contained elastic plastic material properties at 2 K. Loads - The load combination in this analysis was the following: (P+D+T 2 ) P = 4 bar (Helium Pressure) which is the target value for MAWP CT D = (mass of system)(gravity) T 2 = Loads due to thermal contraction With Tuner Loads become - (P+D+T 1 +T 2 ) T 1 = 7500 N

15. SSR1 cryomodule development for PXIEPage 15 Cryogenic Temp. : NO Tuner Results

16. SSR1 cryomodule development for PXIEPage 16 Cryogenic Temp. : Tuner Results

17. SSR1 cryomodule development for PXIEPage 17 Protection Against Failure from Cyclic Loading Model Material - The material model used for this analysis contained elastic perfectly plastic material properties at both 293 K and 2 K.

18. SSR1 cryomodule development for PXIEPage 18 Protection Against Failure from Cyclic Loading Loads - The cycle of loads taken into account for checking the protection against ratcheting had the following steps: STEP 1 - Ramped pressure in the helium space up to 2 bar STEP 2 - Keeping the load from STEP 1 constant, apply thermal cooldown from 293 K to 2 K STEP 3 - Keeping the loads from STEPS 1-2 constant, apply ramped tuner force up to 7500 N STEP 4 - Keeping the loads from STEPS 2-3 constant, increase the pressure inside the helium space to 4 bar STEP 5 - Keeping the loads from STEPS 2-3 constant, reduce the pressure inside the helium space to 2 bar STEP 6 - Keeping the loads from STEPS 2 & 5, remove the tuner force applied at STEP 3 STEP 7 - Keeping the load from STEP 5, remove the thermal cooldown (STEP 2) to return the system to 293 K STEP 8 - The end STEP; remove the last load, STEP 5, still being applied, making the pressure inside the helium space equal to zero Results - By creating a plot of relevant component dimensions versus time between CYCLE 4 and CYCLE 5, it has been demonstrated that there is no plastic deformation in the overall dimensions of the SSR1 resonator system. Therefore, with negligible changing of plastic deformation between the last two cycles the ratcheting criteria is satisfied.

19. SSR1 cryomodule development for PXIEPage 19 ASME BPV Code SSR1 Resonator Summary

20. SSR1 cryomodule development for PXIEPage 20 Tuner System

21. SSR1 cryomodule development for PXIEPage 21 Optimization of Motor support target stiffness for support: 100,000 N/mm required stiffness for support: 70,000 N/mm 1 st shape: doesn’t meet target stiffness 2 nd shape: higher than target stiffness expect to loose stiffness when attached to HV, therefore high 2 nd value was analyzed Motor Case t s mm t E mm h w mm h m mm k N/mm NO83964590,511 NO939645114,160 YES829645102,406 YES929645133,910

22. SSR1 cryomodule development for PXIEPage 22 Optimizing support shape Model & Mesh h w = 96 mm; h m = 45 mm 9 mm arm thickness gives required stiffness Wide arm is needed near casing to meet required stiffness 2 mm extrusion near tuner motor is for support arm clearance 66 mm flat, top section gives T-bar deflection space mesh convergence study was performed to get appropriate element size mesh with element size ranging from 10 mm – 2 mm gave convergence curve in deflection and stress near 3 mm mesh deflection values remained stable and showed convergence mesh with element length of 2 mm was used for support arm

23. SSR1 cryomodule development for PXIEPage 23 Optimizing support shape Results vertical directional deflection was analyzed by selecting the two circular faces of both pins supporting the motor casing min and max values of each face were averaged and used to find stiffness δ avg = 0.009334 mm k = 133,910 N/mm the stress distribution shows that the max equivalent stress occurs near the connection point to the coarse motor σ max = 35.3 MPa, σ allow = 517 MPa this max stress does not exceed the maximum allowable stress of the material the stresses on standard beam orientations influenced support shape Low stress regions were removed as much as possible

24. SSR1 cryomodule development for PXIEPage 24 “True” stiffness Support attached to the HV 8 mm element mesh was used for both the HV and the cavity main focus for the analysis is the support mesh density is appropriate for deflection in this case A = Standard Earth Gravity B = Coarse Tuning Motor force applied to support arms C = Fixed Supports D, E = Coarse Motor Tuning Arm lever force applied to plate F = Tuning Arm force applied to beam pipe of HV to deflect bellows G = Tuning Arm support force applied to HV

25. SSR1 cryomodule development for PXIEPage 25 “True” stiffness Support attached to the HV with cavity δ avg = 0.0124 mm which gives a support stiffness of 100,770 N/mm attached to the HV/cavity meets the target value of 100,000 N/mm and is within 1% of this value Meets the required stiffness and surpasses this value, 70,000 N/mm, by 30.5% the maximum stress of the HV/cavity system occurred in the bellows σ max = 159 MPa, σ allow = 517 MPa This value is less than the allowable stress of the material

26. SSR1 cryomodule development for PXIEPage 26 Acknowledgements Leonardo Ristori Donato Passarelli Margherita Merio SIST Committee Members

27. SSR1 cryomodule development for PXIEPage 27 Thank You QUESTIONS?