Irfu.cea.fr ATLAS-NSW 4 TH MMM WORKSHOP THERMO-MECHANICAL SIMULATIONS FOR THE MM WEDGES (TDR OPTIONS...

Irfu.cea.fr

ATLAS-NSW4TH MMM WORKSHOP

THERMO-MECHANICAL SIMULATIONS

FOR THE MM WEDGES (TDR OPTIONS –

SCREWED QUADRUPLETS)

24-25 of June 2013

Patrick PONSOT & Patrick GRAFFIN for the CEA-Saclay-Irfu group:

F.Bauer, P.Daniel-Thomas, E.Ferrer-Ribas, J.Galan, W.Gamache, A.Giganon, P-F.Giraud, S.Hassani, S.Herlant, S.Hervé, F.Jeanneau, H.LeProvost, O.Meunier, A.Peyaud, Ph.Schune

4th MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT & Patrick GRAFFIN

OUTLINE

2013/06/24-25 | PAGE 2

As reminder, the status presented during the MMM Saclay workshop (on the 18th of April 2013)

New results about thermo-mechanical simulations with 3 screwed modules on the spacer (tension of the mesh has been included,…)

New results about thermo-mechanical simulations with full size wedge screwed on the spacer (segmented skins ?)

Conclusion (2 parts)

• The design of M4 prototype before these new results• Statement for the design of the quadruplets: Modifications of the

prototypes ?


TO KEEP IN MIND !

2013/06/24-25 | PAGE 3

In all cases the thermo-mechanical simulations are made with simplified modeling. The results

must be considered as predictive tendencies and not as absolute values.

Material used for all the simulations:Component PCB Honeycomb StructureMaterial FR4 Aluminum G10 AluminumDensity (Kg/m3) 1950 129.7 1900 2770Young modulus (MPa) 17000 2999 24000 71000Poisson’s ratio 0.37 0.3 0,3 0,3Coefficient of thermal expansion α.K-1 15x10-6 23x10-6 13x10-6 23x10-6

Thermal conductivity (W.m-1.K-1) 0,3 150 0,3 150


AS REMINDER

2013/06/24-25 | PAGE 4

Status on the end of April : Presented at Saclay during the 3rd MMM workshop

The modeling has been

improved !


NEWS ON 2x3 SCREWED MODULES

2013/06/24-25 | PAGE 5

Geometry, boundary and loading conditions• 2x3 modules + spacer• 3 kinematic mounts on the spacer• Self weight + Inclined at 0.704° + temperature gradient in Z direction ΔT=2°C• The tension of the mesh is included: 15N/cm



2013/06/24-25 | PAGE 6

2x3 modules with aluminum frames and aluminum honeycombs, only screwed on their external frame on an aluminum spacer (FR4 skins 0.5mm, no sliding around the screws)

• Displacement for the modules

Sector 5~44µm

~94µm~16µm

Global 3D

Only 16 microns out of the plane, if we can guarantee the full contact with the spacer (planarity)



2013/06/24-25 | PAGE 7

2x3 modules with aluminum frames and aluminum honeycombs, only screwed on their external frame on an aluminum spacer (FR4 skins 0.5mm, no sliding for the screws )

• Stresses for the modules

Sector 5

The increasing of the stresses up to ~111 MPa is localized

around the support (it should be solved with kinematic mounts)

~15 MPa

~111 MPa

Only ~2 MPa on the skins

The increasing of the stresses up to 15MPa is localized around the screws. The detailed design should take in account this effect. Higher will be the stiffness of the

quadruplets, higher will be the stresses around the fixations



2013/06/24-25 | PAGE 8

2x3 modules with aluminum frames and aluminum honeycombs, only screwed on their external frame on an aluminum spacer (FR4 skins 0.5mm, no sliding for the screws)

Statement:

• Addition of the tension of the mesh at 15N/cm is possible without increasing of the displacements

• Remark: In all cases the displacement out of the plane is very dependent of the symmetry and planarity of the components (full contact between the spacer and the modules reduced the Z displacement)

• To keep under control the stresses, we must use the detailed design for the quadruplet according to its evolution inside the MM community

• New questions for MM community: With mechanical prototypes, do we want to test also the screwing of the modules on the spacer frame? Can we measure the stresses with a temperature gradient?

M4


NEWS ON 2 FULL SIZE WEDGES

2013/06/24-25 | PAGE 9

Sector 5

Geometry, boundary and loading conditions• 2 Full size wedges + spacer• 3 kinematic mounts on the spacer• Self weight, Inclined at 0.704°, temperature gradient in Z direction ΔT=2°C• The tension of the mesh is included: 15N/cm• Modification of the boundary conditions for the screwing (2 DoF have been added)



2013/06/24-25 | PAGE 10

Sector 5

Full size wedges with aluminum frames and aluminum honeycombs, only screwed on the external frame of an aluminum spacer (FR4 skins 0.5mm, with 2 DoF for the screws)

• Displacements

~55µm

~105µm~37µm

Global 3D

37 microns out of the plane, if we can guarantee the full contact with the spacer (planarity)



2013/06/24-25 | PAGE 11

Sector 5


• Stresses

Only ~1.5 MPa on the skins

Increasing of the stresses up to ~37 MPa,is localized around the support

The stresses for the skins have been decreased a lot with additional

DoF on the screws.


WITH SEGMENTED SKINS

2013/06/24-25 | PAGE 12

Sector 5

Geometry, boundary and loading conditions• 2 Full size wedges + spacer• 3 kinematic mounts on the spacer• Self weight, Inclined at 0.704°, temperature gradient in Z direction ΔT=2°C• The tension of the mesh is included: 15N/cm• Modification of the boundary condition for the screwing (2 DoF have been added)



2013/06/24-25 | PAGE 13

Sector 5

Full size wedges with aluminum frames and aluminum honeycombs, only screwed on the external frame of an aluminum spacer (FR4 segmented skins 0.5mm, with 2 DoF for the screws)

• Displacement

~38µm

~86µm

~30µm

Global 3D

30 microns out of the plane, but we found “unsticking” in the central part of the spacer



2013/06/24-25 | PAGE 14

Sector 5


• Behavior of the spacer

Out of plane ~30µm

Global 3D

~28 MPa is localized around the supports

Same behavior as the IP wedge



2013/06/24-25 | PAGE 15

Sector 5


• Displacement of the 2 wedges

~22µm~10µm

Displacement out of the plane of the 2 wedges are not the same:10 microns compare to 22 microns (Nota: All the simulations are done

without the spacers inside the drift gap)

HO wedge IP wedge



2013/06/24-25 | PAGE 16

Sector 5


• Stresses

Only ~1.2 MPa on the skins

~23 MPa on the screws Only ~4.5 MPa on the rectangular

tubes which linked the segmented skins (20mmx10mmx1mm)



2013/06/24-25 | PAGE 17


Statement:

• Addition of the tension of the mesh at 15N/cm is possible without increasing of the displacements

• Stresses for the skins can be decreased a lot if we have more DoF around the screws (friction factor is not still taken in account?)

• Segmentation of the skins “introduced” different displacement for the 2 wedges. We should learn a lot of things with the mechanical prototypes (e.g. result with the spacers inside the drift gap)

• Remark: In all cases the displacement out of the plane is very dependent of the symmetry and planarity of the components

Full size skins Segmented skins

Displacement out of plane of the quadruplets (m)

37 HO quadruplet 10IP quadruplet 22

Stresses for the skins 1.5 1.2

Stresses for the screws (MPa) 37 23


Only one panel - Segmented skins ?

2013/06/24-25 | PAGE 18

Only thermal behavior (temperature gradient on Z) for only one full size panel with aluminum frame and aluminum honeycomb, (FR4 skins 0.5mm)

Difference about displacement is less than 5 microns


Only one panel - Segmented skins ?

2013/06/24-25 | PAGE 19

Only thermal behavior for only a full size panel with aluminum frame and aluminum honeycomb, (FR4 skins 0.5mm)

Difference about stresses:Structures: 1,9 MPa to 2,3 MPa

Skins: 0,4 MPa for both


CHECKING WITH SECTOR 7 (45°)

2013/06/24-25 | PAGE 20

Sector 7


~1,5MPa

~37µm

As for sector 5, only ~37 microns out of the plane, but we found also an “unsticking” at the center of the spacer

Global~100µm

~20µm


CHECKING WITH SECTOR 7 (45°)

2013/06/24-25 | PAGE 21


Sector 7

~1,2MPa

~30µm

As for sector 5, only ~30 microns out of the plane, but we found “unsticking” on all the internal bars of the spacer

Global~75µm

~20µm


Before conclusion : Status of the design for M4 prototype

2013/06/24-25 | PAGE 22

Where we stand before this workshop !

2 doublets and 3 drift

panels made with

10mm aluminum

honeycombs

3 kinematic mounts are directly fixed on the central drift panel (4 screws M6)

As in the simulation, all is glued inside the quadruplet and we have spacers inside the drift

gap (~40 ceramic pillars)

Nota: During the production, the mesh can be dismounted and

replaced (the frame of the mesh is screwed on the drift panel)

A tension of 15N/cm is applied on the mesh

The sealing can be tested by putting

pressure up to 6mbars


Before conclusion : Status of the design for M4 prototype

2013/06/24-25 | PAGE 23

Preliminary drawings have been prepared !

But before to launch the manufacturing we need to know exactly the criteria for the qualification of the mechanical prototypes (assembly method with a spacer?)


CONCLUSION 1/3

2013/06/24-25 | PAGE 24

Statement for the design and the fixation of the quadruplets

• The screwing of the quadruplets on the spacer can work if we are able to provide DoF around the screws without lost of the positioning (fixed point, sliding between the quadruplets and the spacer, alignment system)

• Segmentation of the skins “introduced” different deformation of the IP and HO wedges. A high rigidity and planarity of the spacer are required to avoid to amplify this phenomena (Spacer made of stainless steel ?)

• Simulations were conservative for the deformation out of the plan (equivalent Young modulus 17GPa) but… We measured higher stiffness for the panel (+30%, see talk from Fabien, “news from Saclay”), the stresses around the fixation could be increased (tbc)

Sector 5 with mesh tension and

aluminum spacer

3 modules(without DoF for

the screws)

Full size skins(with 2 DoF for

the screws)

Segmented skins(with 2 DoF for the

screws)

Displacement out of plane of the quadruplets (m)

16 37 HO quadruplet 10IP quadruplet 22

Stresses for the skins (MPa) 2 (without DoF) 1.5 1.2

Stresses for the supports (MPa) 111 (without DoF) 37 28


CONCLUSION 2/3

2013/06/24-25 | PAGE 25

Thermal simulations demonstrated that the main issue is the assembly of the quadruplets on the spacer

• Kinematic mounts have been rejected (expansive, complex, risk to lose the absolute positioning after installation…etc.)

• Gluing of the quadruplets on the spacer is the backup option (risk to lose a full sector in case of failure during the assembly)

• Screwing is possible if we have under control the displacements (positioning and alignment)


CONCLUSION 3/3

2013/06/24-25 | PAGE 26

Parameters to have under control the displacements with screwed quadruplets

• All the frames inside a quadruplets should have the same displacements (alignment is only outside) : With spacers inside the drift gap, gluing of all the components (inside a quadruplet) is the best option.

• The local stresses around the supports and fixations must be applied only on the frames (no contact between screws and skins)

• A fix point is needed, but all other fixations should allow the sliding (clearance around the screws)

• Planarity of the spacer and quadruplet (and symmetry of the structures) is required to avoid amplification of the bending (rotation of the frames)

• The material of the spacer can be adapted to reduce the gap between coefficient of thermal expansion (mass, cost, …): to be checked with new simulations


DSM

Irfu

SIS/LCAP (PC N°12, Bt 123)

Patrick PONSOT

Commissariat à l’énergie atomique et aux énergies alternatives

Centre de Saclay | 91191 Gif-sur-Yvette Cedex

T. +33 (0)1 69 08 79 30 | F. +33 (0)1 69 08 89 47

Etablissement public à caractère industriel et commercial | RCS Paris B 775 685 0192013/06/24-25

Thank you for your attention !

| PAGE 27

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Irfu.cea.fr ATLAS-NSW 4 TH MMM WORKSHOP THERMO-MECHANICAL SIMULATIONS FOR THE MM WEDGES (TDR OPTIONS...

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