AUW @ CERN, the 9th of Nov. 09 1

FEA Updates on Structures

(overall ID model)

University of Geneva: G. Barbier, F. Cadoux, A. Clark, D. Ferrère, M. Weber

ATLAS Upgrade WeekCERN, 09-13 of November 2009

AUW @ CERN, the 9th of Nov. 09 2

RECALL of the FE model features [1]

Overall CAD model of ID (part descriptions…PIXEL, Strip BARREL, 2 End Cap, services, Outer Cylinder)

End flange

Outer Cylinder (OC)

6.3 m

End Cap (EC)

Barrel

Pixels

AUW @ CERN, the 9th of Nov. 09 3

RECALL of the FE model features [2]

Baseline used for simulations:PIXEL attached to Barrel (as a lumped mass of 300Kg total)

Pixels

Barrel:5 concentric cylindersPer side: 8 interlinks,4 Superlinks

Pixels

Services for bothPixel and Barrel(100Kg per side)

Pixel Mass location(150 Kg per side) Needs soon a first mechanical model for Pixel

AUW @ CERN, the 9th of Nov. 09 4

Model description & Weight assumptions

Baseline used for simulations:BARREL geometrical model (made of surfaces)

5 cylinders(single skin material)with reinforcing rings

4 Superlinks (to Outer Cylinder)

8 Interlinks(3mm thick)

Bare weight: 103 Kg (no STAVE)from both CAD and FEA…1mm thick

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Model description & Weight assumptions

Baseline used for simulations:Lumped mass to be added onto the BARREL

STAVE weight (720 Kg total)As follows:-Barrel1: 100 Kg-Barrel2: 130 Kg-Barrel3: 150 Kg-Barrel4: 150 Kg-Barrel5: 190 Kg

Ex: Barrel1 lumped mass(surfaces in red)

Service weight (200Kg total)100Kg per side

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Model description & Weight assumptions

Baseline used for simulations:END CAP (EC) geometrical model (made of surfaces)

Inner cone:CFRP material/0.5mm thick

Outer cylinder:Honeycomb 0.3mm CFRP facings / 10mm Nomex core

EC feet:CFRP material / 4mm thick

DIS

K 1

DIS

K 2

DIS

K 3

DIS

K 4

DIS

K 5

EC Disks:All in honeycomb 0.3mm CFRP facings / 10mm Nomex core

AUW @ CERN, the 9th of Nov. 09 7

Model description & Weight assumptions

Baseline used for simulations:

Lumped mass to be added onto EC surfaces

STAVE weight (100 Kg total)Applied to the 5 Disks (proportional to the surfaces)

EC Services weight (100 Kg total)Applied to the Outer cylinder

AUW @ CERN, the 9th of Nov. 09 8

Model description & Weight assumptions

Baseline used for simulations:Outer Cylinder (OC) geometrical model Outer Cylinder (OC):

Honeycomb 2.5 mm CFRP facings / 30mm Nomex core

OC End Flange Honeycomb 1 mm CFRP facings / 20mm Nomex core

Close up on the tiesbetween OC and its flanges

Shape given by servicecross section

AUW @ CERN, the 9th of Nov. 09 9

Model description & Weight assumptions

Baseline used for simulations:Outer Cylinder lumped mass…Polymoderator and services

Polymoderator weight (316 Kg total)Applied to the middle part

Service weight (500 Kg total)Applied to both ends

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Model description & Weight assumptions

Baseline used for simulations:The overall CAD model (all made of surfaces elements)

OC Barrel

EC

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Material mechanical features (CFRP & Honeycomb)

CFRP material(Quasi Isotropic facing, density=1,6)Honeycomb is assumed to be in Nomex

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FEA Overall Model (meshing)

3D model

Model total mass:(given by FEA)M= 3043 Kg

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FEA Outcomes [With OC End flanges; BC#1]

Sagging Uy = 1.24mm Barrel / 0,4mm OCVon Mises stresses: 93 MPa Barrel links

Outer BC’s (handling/cryostat):4 pts (simply supported)

EC and Barrel fixed by 4 pts / OC(2 per side)

AUW @ CERN, the 9th of Nov. 09 14

FEA Outcomes [With OC End flanges; BC#2]

Sagging Uy = 0.7mm Barrel Von Mises stresses: 49 MPa

EC fixed by 4 pts / OCBarrel fixed 6 pts / OC(3 per side)

AUW @ CERN, the 9th of Nov. 09 15

FEA Outcomes [Without OC End flanges; BC#1]

Sagging Uy =1.34mm Barrel / 0.4mm OC Von Mises stresses: 92 MPa (Barrel)

EC and Barrel fixed by 4 pts / OC(2 per side)

AUW @ CERN, the 9th of Nov. 09 16

FEA Outcomes [MODAL shape & Eigen value 1]

z

Modal Shape: Barrel movement along z axis with a slight twisting (freq. : 9 Hz)

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FEA Outcomes [MODAL shape & Eigen value 2]

z

y

Modal Shape: Barrel movement along y axis (freq. : 20 Hz)

AUW @ CERN, the 9th of Nov. 09 18

FEA studies Conclusions and Outlooks

No big issue up to now (Deflection/Stresses of the Barrel can be reduced by a 3rd point) Still need to investigate: The EC design (new baseline ?) The BARREL behavior in case of a DISK conceptual design The PIXEL design to be implemented into the FE Model

Still need to understand/estimate the relative deformations within each detector (what sagging is acceptable for physics?)

This FE model is only to give a first feedback/feeling about the overall behavior (rigidity). And to play with different conceptual designs for cross comparisons.Fine tuning on parameters (material, meshing,…) will be done as soon as the designs are more “realistic”…