1. October 21, 2003LST Mechanical Design Review - SLACN. Yu BaBar IFR Upgrades An FEA Study of the Effects of Adding Brass Plates in the IFR

2. October 21, 2003LST Mechanical Design Review - SLACN. Yu Present BaBar Configuration FEA (Finite Element Model) of BaBar As-built with Doors Off.

3. October 21, 2003LST Mechanical Design Review - SLACN. Yu The Problem Removal of the gap and forward corner plates provides clear access to components in the barrel. Will removal of the gap and corner plates deform the barrel to the point that the gap and corner plates could not be re-assembled?

4. October 21, 2003LST Mechanical Design Review - SLACN. Yu Analysis Determine with Finite Element Analysis (FEA) whether the deformation of the barrel will affect the re-assembly of the gap and corner plates.

5. October 21, 2003LST Mechanical Design Review - SLACN. Yu BaBar FEA Model J. Hodgson (SLAC) created a quarter-model of BaBar for the original BaBar structural analysis.

6. October 21, 2003LST Mechanical Design Review - SLACN. Yu New FEA Model - #1 As-built Present Loads: Solenoid (14000 kg) – 4 points inside lower side plates DIRC (8000 kg) – 14 points from the top & bottom gap plates & on 100 & 50-mm IFR plates Calorimeter (30000 kg) – 4 pts. at outside of mid-plane corner plates Flux bars (8000 kg) – at each corner No end plug weight here

7. October 21, 2003LST Mechanical Design Review - SLACN. Yu New FEA Model - #2 Upgrade Configuration Upgrade Configuration Loads: Solenoid (14000 kg) – 4 points inside lower side plates DIRC (8000 kg) – 14 points from the top & bottom gap plates & on 100 & 50-mm IFR plates Calorimeter (30000 kg) – 2 pts. on bwd. end on outside of mid-plane corner plates and 6 pts. on fwd. end on earthquake wide flange supports Flux bars (8000 kg) – at each corner No end plug weight here

8. October 21, 2003LST Mechanical Design Review - SLACN. Yu New FEA Model - #2 Upgrade Configuration Consider the following extreme scenario: All Forward corner plates are removed Top & bottom gap plates on Forward end are removed Top & bottom gap plates on Backward end are left on All other center gap plates are removed (were not part of original model)

9. October 21, 2003LST Mechanical Design Review - SLACN. Yu New FEA Model - #2 Upgrade Configuration Brass loading: Six layers of brass plate segments are installed in all sections Layers 5, 7, 9, 11, 13, 15

10. October 21, 2003LST Mechanical Design Review - SLACN. Yu FEA Model 2 Consider von Mises stresses: – Max is 18 ksi (occurs on bolts attaching wedge to cradle) (units are in Pa)

11. October 21, 2003LST Mechanical Design Review - SLACN. Yu FEA Model 2 Consider von Mises stresses without the wedge-cradle bolts: – Max range is ~ 10 ksi (units are in Pa)

12. October 21, 2003LST Mechanical Design Review - SLACN. Yu FEA Model 3 - Deflections Model 3 = Model 2 (Upgrade) – Model 1 (As-built) Consider the relative change in position by comparing the vector sum of x,y,z nodal deflections Max overall relative change in position is less than 0.3 mm in the area of the wedge- cradle bolts units are in (m)

13. October 21, 2003LST Mechanical Design Review - SLACN. Yu FEA Model 3 - Deflections The bolt positions on the corner and gap plates are shown here.

14. October 21, 2003LST Mechanical Design Review - SLACN. Yu FEA Model 3 - Deflections Now consider only the nodal points on the x-y plane of bolt holes for corner plates and the ends of the side plates –Fwd end: max change in relative position is ~ 0.2 mm –Bwd end: max change in relative position is ~ 0.3 mm

15. October 21, 2003LST Mechanical Design Review - SLACN. Yu Results Results suggest that the maximum relative movement of the bolt holes and internal component support points on the side plates on the Forward End is ~ 0.3 mm. This also suggests that preliminary results from a year ago are correct: Removal of the gap and forward corner plates to gain access to barrel components seems like a viable option.