Modular Coil Assembly Bolted Joint PDR 2/22/07

1. Modular Coil Assembly Bolted Joint PDR 2/22/07

2. Objectives • The review objectives include... • Define the location of additional inboard bolts • Finalize the material selection and design of the shim and washers • Establish the minimum bolt preloads for both types of joint • Establish the adequacy of the bolted joint design through analysis • consistent with NCSX Structural and Cryogenic Design Criteria and • the NCSX Handbook for Bolted Joint Design • Document the envisioned assembly sequence and assembly requirements

3. Three-Coil Assembly C-C B-C A-B A-A

4. Interface A-B • 25 tapped holes, most on Type-A • 1 through hole Type-B Type-A

5. Interface B-C • 29 tapped holes, most on Type-B Type-C Type-B

6. Interface A-A • 20 tapped holes

7. Interface C-C • 24 through holes • 8 tapped holes

8. A1 is special

9. A1 Welded Adaptor w/ Tapped Hole A-B 2 plcs A-B 3 plcs A-A 4 plcs

10. Inventory of Tapped/Through Holes

11. Tapped Hole

12. Through Hole

13. Assembly Requirements • Position the coils accurately • Minimize gaps

14. Assembly Sequence insulating bushing insulating layer 1- Position coils and measure shim 2- Fabricate and install shim

15. Assembly Sequence (2) Insulating washer 3- Position coils and measure bushing 4- Fabricate and install bushing

16. Assembly Sequence (3) 5- Install ½ in. thk load washer 6- Install spherical washers & nut

17. Bolt Tightening (1) • CAD model layout of wrenches has been performed • Options include low-profile torque wrench, supernut, hydraulic tensioner • Hole catalog being developed by visual inspection, template checking Table A-B based on CAD layout low profile torque wrench

18. Bolt Tightening (2) Supernut Dw=2.5-in D= 2.46-in L=1.93-in T= 1.75-in A286 (4340 is std) Table B-C based on CAD Layout

19. Bolt Tightening (3) Table C-C based on CAD layout

20. Bolt Tightening (4) Table A-A based on CAD layout

21. Bolt Tightening (5) • Layout of hydraulic tensioner is in progress 4.6 DIA 4.9

22. Bolted Joint Parameters (1) MATERIALS-

23. Bolted Joint Parameters (2)

24. Bolt Preload • Nominal preload of 75-kips based on 85% of A286 yield strength • Cool-down relaxation is -4% with Inconel load washer, +2% with Titanium • Preload uncertainty for hydraulically tensioned studs w/ ultrasonic inspection

25. Joint Stiffness min preload joint separates at 90-kip

26. Maximum Shear Load • Local model analyzed for 25-kips shear • Max bushing stress is 67.4-ksi • Compare to bushing material: • Compressive strength = 60-ksi • Min bearing strength = 30-ksi • Max shear load = ~11-kip Through hole Local FEA model Tapped hole

27. abint abinb Global Analysis w/ Bonded Flange Joint • Three coils w/ rotational bc, bonded flange joint, 2T EM load • Shear, normal force by region determines required friction coefficient • Clamping force increased by addition of inboard bolts compression (blue) without inb bolts inboard regions with inb bolts bolts added Interface A-B Normal pressure mu to prevent slip

28. Global Analysis (2) • Additional inboard bolts reduces required coefficient of friction to 0.45 • Bolts added to A-B (3), B-C (4), and A-A (2) interfaces

29. Friction Testing • Friction tests with diamond, alumina shim coatings can increase mu to ~0.5 • Design criteria limits value to 2/3 achievable or 0.3 Standard shim concept Additional bolts Custom shims at interface B-C

30. Location of Inboard Holes (1) Type-A, Flange Datum-D, Winding Side-A

31. Location of Inboard Holes (2) Type-A, Flange Datum-E, Winding Side-B

32. Location of Inboard Holes (3) Type-B, Flange Datum-D, Winding Side-A

33. Location of Inboard Holes (4) Type-B, Flange Datum-E, Winding Side-B

34. Location of Inboard Holes (5) Type-C, Flange Datum-D, Winding Side-A

35. Global Analysis w/ Equivalent Bolt Model • Three coils w/ rotational bc, discrete attachments, sliding interface, 2T EM load • Inboard bolts added, mu=0.3 • Results show slipping w/ “residual” shear load taken by bolts • Some shear loads >11-kips limit for bushing Interface A-B

36. Global w/ Bolts (2) Interface B-C

37. Global w/ Bolts (3) • Load step difference (preload/EM) used to determine alternating bolt load • Results preliminary, but suggest alternating load is ~8% of preload Interface A-A

38. Global w/ Bolts (4) • No problem here Interface C-C

39. Conclusion • Minimum friction condition (mu=0.3) does not work for all bolts, however • both analyses indicate that the friction coefficient seen in testing is adequate • Tests of bolted joint mockups are planned • Additional analysis needed to check joint fatigue life LVDT connecting rods Test joint Shear Test Setup -K Freudenberg

40. Conclusion (2) • The review objectives include... • Define the location of additional inboard bolts • Hole location drawings are being prepared. • Finalize the material selection and design of the shim and washers • Hardware models/drawings are in final final checking for • procurement of tension and shear test joint components. • Establish the minimum bolt preloads for both types of joint • Preload defined according to design criteria. • Access and tooling for bolt tightening is being evaluated. • Establish the adequacy of the bolted joint design through analysis • consistent with NCSX Structural and Cryogenic Design Criteria and • the NCSX Handbook for Bolted Joint Design • Bolt and joint have been shown to have adequate strength if friction • is increased or other shear constraint is considered. • Fatigue evaluation is in progress. • Document the envisioned assembly sequence and assembly requirements • Basic assembly sequence has been defined, but details TBD. • Hole catalog and planned coil-to-coil fitup tests are critical.