1. ATLAS ITk Upgrade: SLIM Update
Diego Álvarez Feito
PH-DT Engineering Office, CERN
CERN, January 2015
20/01/2015

2. SLIM Stave: Mechanical Analysis
Mechanical/deformation analysis of two ‘longeron’ design concepts
Mass optimisation started by S. Michal
Six ribs (0.3mm thick) connecting the longerons
Module cells & barrel section assumed not to play structural role
“Open” Longerons
Longerons with “stiffening box”
20/01/2015

3. SLIM Stave: Open Longeron
“Open” Longerons
Sandwich construction for longerons
0.2mm thick CFRP longerons (Quasi-isotropic 67µm ply, [-60,0,60])
1.5mm thick core (PVC foam, 80kg/m3)
CFRP Ribs (Quasi-isotropic 67µm ply, [-45,0,45,90])
Cells modelled as forces (applied to bolt holes)
Tilted Cells: 8.99g each
Barrel Cells: 36.4g each
Quasi-kinematic supports at the ends of the cooling lines
Layered shells
Solid elements
Layered shells
Unidirectional K13D has been assumed in all the simulations to see the lower limit of the deformation. However, alternatives such as M55J or M50J will be investigated next.
Woven plies could also be considered next to meet specific thickness requirements.
20/01/2015

4. Open Longeron: Results
Total mass: 525g
Max. deformation (Gravity) ≈ 192µm
20/01/2015

5. Open Longeron + Central Covers: Results
Top and bottom covers for increased stiffness
0.2mm thick CFRP (Quasi-isotropic 67µm ply, [-60,0,60])
Bonded to longerons and first two ribs
Total mass: 548g
Max. deformation (Gravity) ≈ 154µm
20/01/2015

6. SLIM Stave: Longeron + Stiffening Box
Sandwich section
0.3mm skins (67µm ply, [-45,0,45,90])
1.5mm thick core (PVC foam, 80kg/m3)
Stiffening box
0.3mm skins (67µm ply, [-45,0,45,90])
2mm thick top core (PVC foam, 80kg/m3)
Longerons with “stiffening box”
CFRP skins: Layered shells
Solid bodies: Solid elements
CFRP Ribs (Quasi-isotropic 67µm ply, [-45,0,45,90])
Cells modelled as forces (applied to bolt holes)
Tilted Cells: 8.99g each
Barrel Cells: 36.4g each
Quasi-kinematic supports at the ends of the cooling lines
Unidirectional K13D has been assumed in all the simulations to see the lower limit of the deformation. However, alternatives such as M55J or M50J will be investigated next.
Woven plies could also be considered next to meet specific thickness requirements.
20/01/2015

7. Longeron with SBox: Results
Total mass: 586g
Max. deformation (Gravity) ≈ 153µm
20/01/2015

8. Longeron + Reinforced SBox
Core at the top of stiffening box made out of QI T300 for increased inertia
Total mass: 633g
Max. deformation (Gravity) ≈ 95µm
20/01/2015

9. Future Work Material optimisation
Alternative materials (e.g. M55J, M50J, M46J)
Optimised layups and skin thickness
Structural analysis/integrity of tilted cells
20/01/2015