analysis of d2 collaring operation

1. analysis of d2 collaring operation S.Farinon, P.Fabbricatore, A.Bersani Oct. 2nd 2019

2. Collaring mechanism • each aperture is individually collared • a pressure is applied to align the holes, the keys are inserted, the pressure is released

3. 2D FE modeling of winding • FE model of winding is built piling up the turns starting at the pole • turns are bigger than nominal dimensions at 70 MPa • turn dimensions are set to get the measured coil dimensions @ 70 MPa • collaring force obviously depends on the coil dimensions midplane

4. measured coil dimensions • dimension of manufactured coils @70 MPa with respect to nominal:

5. measured coil dimensions • dimension of manufactured coils @70 MPa with respect to nominal: • half-dimension of apertures @70 MPa with respect to nominal:(aperture V1 and V2 have missing 0.15 mm of kapton per coil in the midplane)

6. collaring force per unit length f • the force per unit length calculated by ANSYS is nearly linear with respect to the half-dimension of the aperture @70 MPa

7. total collaring force F • F = f×1.2 (lenght of straight section) + H (estimated contribution of the ends) this point is the most significative for the mechanicalanalysis because the aperture V2 repairedunderwentseveral «massage» cycles

8. 3D FE model of winding • to understand the level of stress reached in the coil ends during collaring of aperture V2 repaired I’m working on a detailed 3D model(no results to show yet) • particularly important could be the tapered fillers put on the midplane below coil ends

9. coil ends tapered fillers • ASG dimensioned the coil ends tapered fillers in the following way for all the apertures • this was ok for apertures V1 and V2, but possibly too big for the aperture V2 repaired, considering its dimensions at 70 MPa (+0.4 mm) and the additional 0.3 mm of kapton in midplane.

10. analysis of d2 YOKING operation S.Farinon, P.Fabbricatore, A.Bersani Oct. 2nd 2019

11. Yoking mechanism • once collared, the aperture are inserted inside the Al sleeves • then a pressure is applied to the yokes to close the 1.2 mm gap, the C-clamps are inserted, the pressure is released • calculated and measured force are: • calculated force per unit length: 256 tons/m • calculated total force: 410 tons • measured force: 370 tons

12. strain gauges readings strain gauge position • during yoking of aperture V2 repaired only 1 strain gauge was working • under pressure: • calculated transverse strain: -346 mm/m • measured transverse strain: -315 mm/m • pressure relieved: • calculated transverse strain: -248 mm/m • measured transverse strain: -225 mm/m • longitudinal strain is not calculated (2D FE analysis in plane stress); measured values are around 1/3 of the measured transverse values

13. feedback on prototype S.Farinon, P.Fabbricatore, A.Bersani Oct. 2nd 2019

14. 1. Coil dimensions • the collaring of the aperture V2 repaired assessed that, if the coils are 0.4 mm bigger than nominal @70 MPa, the stress in the winding due to collaring is too large to be sustained by the system • prototype coil dimensions @70 MPa have to be: • >0 to get the proper pre-load • <0.2 mm bigger than nominal to ensure a safe collaring operation

15. 2. Straight section collars • removable poles have been eliminated(in addition to an excess of insulation of the exit, they caused the malfunctioning of the I aperture damaging 20 strands out of 36 in the jump) prototype short model

16. 3. Connection side collars • the passage for the exit has been reduce in width and height to reinforce the collar prototype short model

17. 4. Exit box • the exit box has been modified accordingly prototype short model

18. 5. Pole end spacer • the survey circular hole has been removed • the square hole (needed to keepthe filler in the right position during winding) has beenreduced and after windingwill be filled by gluing aG11 block

19. Iron yoke lamination • Following the advice from the international design review, hold on March 2019, we modified the iron lamination to include the circular support short model prototype

20. thanks for your attention S.Farinon, P.Fabbricatore, A.Bersani Oct. 2nd 2019