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INFN Milano

ATLAS PIXEL Inserted B-Layer Eng. Meeting 3 February 2009. Wrap up of the thermal and thermo mechanical simulation on the IBL stave Simone Coelli Mauro Monti. INFN Milano. EDMS PAGES WITH REPORT ON THE FEM SIMULATIONS. ATL-IP-EA-0002 In Work

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INFN Milano

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  1. ATLAS PIXEL Inserted B-Layer Eng. Meeting 3 February 2009 Wrap up of the thermal and thermomechanicalsimulation on the IBL staveSimone CoelliMauro Monti INFN Milano

  2. EDMS PAGES WITH REPORT ON THE FEM SIMULATIONS ATL-IP-EA-0002In Work “Thermo mechanical simulation of the homogeneous stave” 1-REPORT ON THE NEW STAVE THERMO-MECHANICAL FEM SIMULATIONS FOR ATLAS PIXEL DETECTOR B-LAYER REPLACEMENT 2-FINITE ELEMENT METHOD VALIDATION REPORT FOR THERMO-STRUCTURAL SIMULATIONS ON THE NEW STAVE COOLING PIPES Will be soon upgraded with new updated summary report documents on the FEM simulations

  3. SUMMARY: The purpose of this document is to summarize the results of FEM simulations carried out till now on the new B-Layer Stave concept for the Atlas Pixel Detector. Simulation Finite Element Analysis software used is ANSYS code (11.0). Cross-check calculation have been made using the Classical Laminate Theory (CLT). The software ESAComp has been used for a cross-check of some laminate thermal expansion coefficient (CTE). The following subjects have been studied: • VALIDATION OF THE METHOD: comparison of ANSYS and CLT results for easy to handle problems • THERMAL STEADY-STATE: temperature field on the new stave with pipe cooling and power on (max heat flux from modules 7200 W/m2) • STATIC STRUCTURAL MECHANICS: stress and deformation in the composite pipe caused by the internal pressure (design pressure 150 bar) and composites CTE calculation (using a ΔT). • THERMO-MECHANICAL SIMULATION: full length stave (800 mm) stress and deformation induced by the thermal field, cooling down the stave to -40°C from the ambient temperature 20°C, considering both the alternatives with power on modules or not.

  4. VALIDATION OF THE METHOD Comparison of ANSYS and CLT results for easy to handle problems These mechanical simulations were performed with standard load conditions provided by the science of construction and the FEM results were compared with the theoretical calculated values, in order to validate the FE models and the boundary conditions applied. The FE models used have the same characteristics (type of elements, element dimensions, number of elements, etc.) of the components in the Stave FE model We carried out some mechanical simulations on a pipe under different loading conditions. The pipe materials in the simulations are aluminium (isotropic) and composite carbon fiber/epoxy laminate with two different lay-up.

  5. VALIDATION OF THE METHOD Single ply monoaxial stress simulation, changing fibers orientation .

  6. Single ply biaxial stress simulation, changing fibers orientation .

  7. Single ply biaxial stress simulation like in a cylindrical pressure vessel (Mariotte theory) changing fibers orientation .

  8. Single ply shear stress simulation, changing fibers orientation.

  9. Single ply biaxial stress plus shear stress simulation, changing fibers orientation.

  10. Single ply thermal strain due to uniform heating simulation, changing fibers orientation.

  11. Single ply thermal strain due to uniform heating simulation and mechanical stress, changing fibers orientation.

  12. LAMINATE monoaxial stress simulation, changing lay-up.

  13. LAMINATE biaxial stress simulation, changing lay-up.

  14. LAMINATE ply biaxial stress simulation like in a cylindrical pressure vessel (Mariotte theory) , changing lay-up.

  15. CARBON FIBER COMPOSITE PIPE biaxial stress simulation as a cylindrical pressure vessel, axial symmetric shell element changing lay-up, OD, thickness.

  16. CARBON FIBER COMPOSITE PIPE biaxial stress simulation as a cylindrical pressure vessel, Looking at the strain and stress of the laminate global and in the single plies.

  17. PIPE FE MODEL • The main characteristics of the pipe FE model are the following: • OUTSIDE DIAMETER D = 3.0 mm • INNER DIAMETER d = 2.4 mm • WALL THICKNESS t = 0.30 mm • LENGTH l = 100 mm • AVERAGE RADIUS Rm = 1.35 mm • FE MODEL ELEMENTS SOLID186 STRUCTURAL for aluminium pipe • SOLID186 LAYERED for composite pipe • NUMBER OF ELEMENTS 3200 • (n.32 in the cross section x n.100 along longitudinal axis) • ELEMENT DIMENSIONS 0.3 x 0.3 x 1 (length) mm CARBON FIBER COMPOSITE OR METALLIC PIPE MECHANICAL SIMULATIONS FOR VALIDATION • COMPOSITE LAMINATE – LAY UP ± 54.7 • Carbon Fiber : T-300 (HR) • Matrix: Epoxy • Lay-up: 2 layers -54.7/+54.7 • Layer thickness: 0.15 mm • Vf : 60% • COMPOSITE LAMINATE – LAY UP 0-90-0 • Carbon Fiber : T-300 (HR) • Matrix: Epoxy • Lay-up: 3 layers 0-90-0 • Layer thickness: 0.10 mm • Vf : 60%

  18. AXIAL TENSILE LOAD F FE MODEL CONSTRAINTS Pipe end face 1 (at X=0 mm) : all nodes constrained UX,UY,UZ Nodal solution - displacement vector sum Amplified scale (10) Element solution - stress along fibers in layer 1

  19. SUPPORTED PIPE DEFLECTION DUE TO GRAVITY EFFECT

  20. CANTILEVERED PIPE DEFLECTION DUE TO GRAVITY EFFECT

  21. PIPE INTERNAL PRESSURE Pipe subjected to internal pressure and hydrostatic head pressure. FE MODEL CONSTRAINTS Pipe end face 1 (at X=0 mm): all nodes constrained UX,UY,UZ (see picture 19)

  22. STAVE SIMULATIONS WITH DIFFERENT MESH

  23. THERMAL STEADY-STATE SIMULATIONS THERMAL STEADY-STATE calculation of the temperature field on the new stave with pipe cooling and power on (max heat flux from modules 7200 W/m2). Internal wall pipe temperature set to 0° C. Mono-pipe and bi-pipe cases.

  24. THERMAL STEADY-STATE SIMULATIONS THERMAL STEADY-STATE: temperature field on the new stave with pipe cooling and power on (max heat flux from modules 7200 W/m2). See next table for the results. Thermal simulation with carbon pipe - nodal temperatures resulting Thermal simulation with aluminum pipe - nodal temperatures resulting Thermal simulation with titanium pipe - nodal temperatures resulting • Comparison between staves with different pipe materials: • Carbon fiber composite (0.3 mm) • Aluminum (0.3 mm) • Titanium (0.1 mm)

  25. THERMAL STEADY-STATE SIMULATIONS THERMAL STEADY-STATE: temperature field on the new stave with pipe cooling and power on (max heat flux from modules 7200 W/m2). See next table for the results. Thermal simulation with carbon pipes - nodal temperatures resulting Thermal simulation with aluminum pipes - nodal temperatures resulting Thermal simulation with titanium pipes - nodal temperatures resulting • Comparison between staves with different pipe materials: • Carbon fiber composite (0.3 mm) • Aluminum (0.3 mm) • Titanium (old value 0.3 mm)

  26. THERMAL STEADY-STATE SIMULATIONS summary table

  27. COMPOSITE PIPE STATIC STRUCTURAL MECHANICS The materials database which we refer for the simulations, is located at the following web address: http://dgiugni.web.cern.ch/dgiugni/upgrade/simulation/ In the database are collected the known materials mechanical and thermal properties. PIPE 3D FE MODEL PIPE ELEMENTS COORDINATE SYSTEMS FOR LAYERED ELEMENTS ORIENTATION • The materials used for the composite pipe simulations are : • Carbon fiber: T300 HR • Matrix: Epoxy, with two different CTE (70 ppm/C or 110 ppm/C) • Volume fiber ratio (Vf) : 60% (baseline) or, alternatively, 30% (*) • (*) For the carbon pipe with lay-up [54,7 / -54,7] also have been carried out simulations with Vf = 40%, 50% and 70%,only for the calculation of the CTE.

  28. Composite pipe CTE evaluation using a ΔT as input to derive the lengthening Vf=30%

  29. Composite pipe CTE evaluation using a ΔT as input to derive the lengthening Vf=60%

  30. Ply calculation for a composite pipe with internal pressure (design pressure 150 bar) - Max stress- safety factor (Tsai-Hill failure criterium)- strain (using transversal strain for tightness verification)

  31. Optimization of the carbon pipe • The design of the laminate of the pipe should satisfy three basic criteria: • 150 bar test pressure with minimum safety factor SF = 4 • Stay tight under pressure, transversal plies strains εT≤ 0.1%, in order to avoid the microcracks growth • Match the longitudinal CTE of the other materials (about -2 ppm/C for the CFRP Omega support with lay-up [0/60/-60]S2 and -0.7/+0.6 ppm/C for the carbon foam). From the simulation results the best lay-up matching the three criteria are: [45 / -45] or [±55/±40]

  32. THERMO-MECHANICAL SIMULATIONS • 3D FE MODELS CHARACTERISTICS • All the simulations have been executed with 3D FE models, for both the different geometries (mono-pipe and bi-pipes stave). • The 3D FE models main characteristics are the following: • Model length [mm] 800 • Elements typesHexahedral 20 nodes bricks • For Thermal analysis: element Solid90 • For Structural analysis: element Solid186 • “structural type” for isotropic materials • “layered type” for composite materials • Number of elements 94,750 for mono-pipe stave geometry • 88,000 for bi-pipes stave geometry • Elements typical dimensions [mm]0.3 x 0.3 (sides) x 3.2 longitudinal length • Ratio length/side  10 • Meshing techniquesPipes and omega support: mapped mesh in volume • Carbon Foam: free extruded mesh • Elements coordinate system orientedCarbon pipes and omega (composite materials) • Contacts between parts: Merged nodes Constraints diagram

  33. THERMO-MECHANICAL SIMULATIONS:to determine the behavior (deformation and stress) of the full length stave subjected to a temperature decrement as:1-A fixed ΔT = -60 C°2- The nodal thermal field from the previous thermal analysis (assuming the temperature of the inner surface of the cooling pipes as 0°C).The ΔT value of -60 C° is determined by the difference between the minimum temperature value of the cooling fluid in the pipes (-40 °C) and the environment temperature, that we assume as 20 °C. So, having fixed to 0°C the temperature of the inner surface of the cooling pipes in the thermal analysis , we consider 60°C the temperature of the non deformed stave FE model in the mechanical environment. • RESULTS EVALUATED IN THERMO-MECHANICAL SIMULATIONS • We want evaluate the following things: • Maximum stave bow in the middle length – UZ [µm] • Maximum stave deformation – USUM [µm] • Maximum Von Mises stress in the carbon foam – SEQV [MPa] • Maximum compression stress in the carbon foam – SX [MPa] • Maximum shear stress in the carbon foam – SXY [MPa]

  34. THERMO-MECHANICAL SIMULATIONS Thermo-mechanical simulation with carbon pipe: carbon foam Von Mises stress Thermo-mechanical simulation with carbon pipe: Stave bow Thermo-mechanical simulation of the stave with one carbon pipe

  35. THERMO-MECHANICAL SIMULATIONS Thermo-mechanical simulation with Titanium pipe: Stave bow Thermo-mechanical simulation with Titanium pipe: carbon foam Von Mises stress Thermo-mechanical simulation of the stave with one Titanium pipe

  36. THERMO-MECHANICAL SIMULATIONS Thermo-mechanical simulation with Aluminum pipe: Stave bow Thermo-mechanical simulation of the stave with one Aluminum pipe

  37. THERMO-MECHANICAL SIMULATIONS Thermo-mechanical simulation with carbon pipes: carbon foam Von Mises stress Thermo-mechanical simulation with carbon pipes: Stave bow Thermo-mechanical simulation of the stave with two carbon pipes

  38. THERMO-MECHANICAL SIMULATIONS summary table

  39. THERMO-MECHANICAL SIMULATIONS

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