1. NSTX outer TF leg analysis (with diamonds not uniformly distributed) *Full 360º model *Al blocks connected to springs to simulate umbrella structure (stiffness is calculated from HM’s vv model) *diamonds are exactly in the bays that are possibly to place them. *standard (full or partial) diamonds have intersections at exactly the TF coil center. Non-standard (shorter) diamond don’t. *rings are exactly at the position of existing turn buckle. Bay A Non-standard (short) diamond bar standard diamond

2. standard (partial) diamond standard (full) diamond Intersection exactly at the coil center A3,41, 2 BY C0 D03? E0 F01, 3, 2 GY HY I1, 3, 42, JY K31, LY Bay F Bay Std diamond, 1,3 upper, 2,4 lower Non-Std diamond (shorter), 1,3 upper, 2,4 lower

3. Pinned ring (DIA=2.5”) and diamond bar (2”x2”) Max theta displacement=39mm (1.54”) --Non-uniformly distributed diamonds cause TF coils and rings to deform --welded rings are required to reduce the deflection in horizontal plane. Max coil stress is ~500MPa (72.5ksi), but can be reduced by adding ss case to the coil. Fmag Fmag (OOP) Fmag Stess here is 350MPa

4. welded ring (5” rect tube with 3/8” thickness) and 5 standard full diamonds (2”x2”) Click to show animation (360º rotation). The 1 st picture, from left is Bay A. Max theta displacement reduced to 18mm (0.71”), total disp is 20mm.

5. welded ring (5” rect tube with 3/8” thickness) and 5 standard full diamonds (2”x2”) Bay E High coil stress at the connection between coil and ring: ~500MPa (72.5ksi), and at the connection between coil and Al. block: ~250MPa (36.3ksi) But these can be reduced by adding ss case of Peter’s design: ring TF ss case Max stress here

6. welded ring (5” rect tube with 3/8” thickness) and 5 standard full diamonds (2”x2”) Bay B Max stress here Ring bending stress very high at the connection between bays with diamond and bays without diamond. Reinforcement for the ring will be required at these places. Bay with diamond

7. welded ring (5” rect tube with 3/8” thickness) and std full and partial diamonds (2”x2”) Click to show animation (360º rotation). The 1 st picture, from left is Bay A. Max theta displacement reduced to 18mm (0.71”), total disp is 21mm.

8. welded ring (5” rect tube with 3/8” thickness) and std full and partial diamonds (2”x2”) Max coil stress and max hoop stress both at the connection of coil and ring. Bay E

9. welded ring (5” rect tube with 3/8” thickness) and std and non-std diamonds (2”x2”) Click to show animation (360º rotation). The 1 st picture, from left is Bay A. Max theta displacement reduced to 16mm (0.7”), total disp is 19mm.

10. welded ring (5” rect tube with 3/8” thickness) and std and non-std diamonds (2”x2”) Max coil stress and max hoop stress both at the connection of coil and ring. Adding non-std diamond causes the empty bays (C,D,E) to have higher coil stress. Bay E

11. Summary 1.Pinned ring not recommended: results in larger coil displacement (1.5”) upon extreme negative PF curr. 2.Welded ring recommended: can correct the non-uniform distribution effect of diamonds. 3.High stress produced at the connections of Al block--TF coil, TF coil--ring, ss case as Peter’s design will help to reduced it. 4.High bending stress in the ring happens at the joint between bay with diamond and bay without diamond, the ring requires reinforcement at these places. ring TF ss case