irfu.cea.fr atlas-nsw 4 th mmm workshop thermo-mechanical simulations for the mm wedges (tdr options...
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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 ?
4th MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT & Patrick GRAFFIN
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
4th MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT & Patrick GRAFFIN
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 !
4th MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT & Patrick GRAFFIN
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
4th MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT & Patrick GRAFFIN
NEWS ON 2x3 SCREWED MODULES
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)
4th MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT & Patrick GRAFFIN
NEWS ON 2x3 SCREWED MODULES
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
4th MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT & Patrick GRAFFIN
NEWS ON 2x3 SCREWED MODULES
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
4th MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT & Patrick GRAFFIN
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)
4th MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT & Patrick GRAFFIN
NEWS ON 2 FULL SIZE WEDGES
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)
4th MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT & Patrick GRAFFIN
NEWS ON 2 FULL SIZE WEDGES
2013/06/24-25 | PAGE 11
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)
• 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.
4th MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT & Patrick GRAFFIN
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)
4th MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT & Patrick GRAFFIN
WITH SEGMENTED SKINS
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
4th MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT & Patrick GRAFFIN
WITH SEGMENTED SKINS
2013/06/24-25 | PAGE 14
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)
• Behavior of the spacer
Out of plane ~30µm
Global 3D
~28 MPa is localized around the supports
Same behavior as the IP wedge
4th MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT & Patrick GRAFFIN
WITH SEGMENTED SKINS
2013/06/24-25 | PAGE 15
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 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
4th MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT & Patrick GRAFFIN
WITH SEGMENTED SKINS
2013/06/24-25 | PAGE 16
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)
• 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)
4th MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT & Patrick GRAFFIN
NEWS ON 2 FULL SIZE WEDGES
2013/06/24-25 | PAGE 17
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)
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
4th MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT & Patrick GRAFFIN
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
4th MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT & Patrick GRAFFIN
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
4th MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT & Patrick GRAFFIN
CHECKING WITH SECTOR 7 (45°)
2013/06/24-25 | PAGE 20
Sector 7
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)
~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
4th MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT & Patrick GRAFFIN
CHECKING WITH SECTOR 7 (45°)
2013/06/24-25 | PAGE 21
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)
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
4th MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT & Patrick GRAFFIN
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
4th MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT & Patrick GRAFFIN
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?)
4th MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT & Patrick GRAFFIN
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
4th MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT & Patrick GRAFFIN
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)
4th MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT & Patrick GRAFFIN
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
4th MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT & Patrick GRAFFIN
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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