1. GANIL-SPIRAL2 DESIGN OFFICE MECHANiCAL SIMULATION WITH
Mechanical Simulation for Detectors
GANIL-SPIRAL2 DESIGN OFFICE
MECHANiCAL SIMULATION WITH
F.E.A. (Finite Element Analysis) ANSYS

2. What is F.E.A. (Finite Element Analysis) ?
Mechanical Simulation for Detectors
What is F.E.A. (Finite Element Analysis) ?
Finite element analysis (FEA) is numerical method used to solve typical problem including :
structural mechanics,
heat transfer,
fluid flow
electromagnetic field.
It can be applied to many physical fields as long as : homogenous and continuous material
The finite element method formulation of the problem results in a system of algebraic equation. The method yields approximate values of the unknowns at points over the domain.
To solve the problem, it subdivides a large problem into smaller, simpler parts that are called finite elements. All the finite elements create a mesh.
The simple equations that model these finite elements are then assembled into a larger system of equations that models the entire problem.
Mesh exemple : different type and size of elements

3. Why ANSYS? Mechanical Simulation for Detectors
ANSYS is one of the most common software for F.E.A. for wide range of physical and engineering problems
It was selected in 2012 by all CNRS/IN2P3 research labs after a common global specification describing our needs . The call for tenders was sent to 5 different software suppliers.
Now all license are provided by CNRS/IN2P3 (no direct cost for GANIL).
All trainings on the different modules are provided by ANSYS France (Paris and Lyon).

4. VAMOS Multi-wire Support Frame VAMOS Ionization Chamber
Mechanical Simulation for Detectors
Examples :
ACTAR vacuum chamber
Static load : vaccum (stress)
ACTAR anode plate
Static load : vaccum (displacement)
VAMOS Multi-wire Support Frame
Static load : traction on each wire
VAMOS Ionization Chamber
CFD analysis : pressure and velocity of gasflow
REGLIS-SIRIUS Multi-Diag. Chamber
Static + Dynamic load : weight and vacumm + Sismic spectrum

5. Vacuum Chamber (M. Michel)
Mechanical Simulation for Detectors
1- ACTAR
Vacuum Chamber (M. Michel)
STEP 1 : CAD model
STEP 2 : Simplified calculation model
St Steel Ep. 7
St Steel Ep. 20
Alu. Ep. 20
STEP 3 : Mesh
Alu. Ep. 20

6. Ultimate Strength (MPa)
Mechanical Simulation for Detectors
1- ACTAR Vacuum Chamber (M. Michel)
STEP 4 : Boudary Conditions and Loading
STEP 5 : Results (post-processing)
Alu. 5083
Stainless Steel 316L
Young Modulus(MPa)
70000
200000
Density (g/cm3)
2.7
7.9
Yield Strength (MPa)
290
320
Ultimate Strength (MPa)
360
610
CONCLUSION : Max stress is 15MPa. This value is less than Yield strenth of stainless steel => OK

7. 2- ACTAR Anode Plate (M. Michel) Mechanical Simulation for Detectors
STEP 3 : Refined Mesh
STEP2 : Calculation Model
STEP 4 : Load (pressure)

8. 2- ACTAR Anode Plate (M. Michel) Mechanical Simulation for Detectors
Alu. 7075
Stainless Steel 316L
Module d’Young (MPa)
72000
200000
Masse volumique (g/cm3)
2.8
7.9
Limite élastique (MPa)
505
320
Résistance à la rupture par traction (MPa)
570
610
STEP 5 : RESULTS
- Maximum stress in material => less than Yiel Strength threshold => OK
- BUT The displacement in the aluminium sheet : 5.4mm => will introduce problems for connexion and wear due to material fatigue => NO
CONCLUSION : We Propose to use Stainless steel instead of Aluminium

9. 3- Multi-wires VAMOS Support Frame (M. Michel)
Mechanical Simulation for Detectors
3- Multi-wires VAMOS Support Frame (M. Michel)
3000 x Vertical Tungsten Wires thickness =20µm on length 1050mm
150 x Horizontal Tungsten Wires thickness 20µm on length 200mm
- Traction on each wire : weight 20g
Material
section
Max Displacement en mm
Weight Kg
Stainless Steel
plain
0.05 17
Hollow section
0.11 5
Aluminium
0.13 6
0.3
1.7
CONCLUSION : Specific steel to limit deformation /displacement => steel 315 => OK

10. 4- VAMOS Gas Flow in Ionization Chamber (C. BD)
Mechanical Simulation for Gaseous detectors
4- VAMOS Gas Flow in Ionization Chamber (C. BD)
C.F.D. =Computationnal Fluid Dynamic => Simulate gas flow inside a chamber
The Code used is a sub-module of ANSYS called CFX
The behaviour of the gas is simulated and NOT the chamber itself
STEP 2 : Simplified MODEL
Gas INLET
1000 mm
200 mm
400 mm
Gas OUTLET
STEP 3 :MESH
The mesh represents the volume of the gas inside the chamber

11. 4- VAMOS Gas Flow in Ionization Chamber (C. BD)
Mechanical Simulation for Detectors
4- VAMOS Gas Flow in Ionization Chamber (C. BD)
STEP 5 : RESULTS
Gas : Isobutane
Density ρ=2.53 kg/m3
Viscosité : 6.87 x 10-6 Pa.s
Outlet pumping flowrate
Internal pressure 50 mbar
200cm3/min => laminar
STEP 4: Load and boundary conditions
1000cm3/min
Conclusion : increasing the flowrate does not solve the problem of gas flow near the corner of the chamber

12. 5- S3 REGLIS-SIRIUS Diagnostic chamber -in progess (F. Lutton)
Mechanical Simulation for Detectors
5- S3 REGLIS-SIRIUS Diagnostic chamber -in progess (F. Lutton)
Sismic calculation : the aim is to demonstrate that the chamber equiped with its diags and pumps cannot fall in case of earhquake. (ASN requirement for all equipement more >500 kg for SPIRAL2 and Experimental areas)
STEP 1 : CAD model
STEP 2 : Simplified model
Each diag or pump represent by its weight

13. 5- S3 REGLIS-SIRIUS Diagnostic chamber -in progess (F. Lutton)
Mechanical Simulation for Detectors
5- S3 REGLIS-SIRIUS Diagnostic chamber -in progess (F. Lutton)
Type of calculation : Dynamic Modal-Spectral analysis
STEP 3 : Mesh
STEP 4 : Boundary conditions and Load
Processing time depends on mesh size… the modal analysis can be quite long but usually less than 30 min.

14. THANK YOU FOR YOUR ATTENTION
Mechanical Simulation for Detectors
THANK YOU FOR YOUR ATTENTION
ANY QUESTIONS ?