Opportunité et défis de l'utilisation des composites pour l'automobile

Transcription

1 Opportunité et défis de l'utilisation des composites pour l'automobile C. Binetruy 1, O.Allix 1, D. Guillon 3, Y. Amossé 4 1 GeM 2 LMT Cachan 3 CETIM (COMP INNOV : Composite Innovation Openlab) 4 Faurecia (Chaire Faurecia / Centrale Nantes) christophe.binetruy@ec-nantes.fr

2 Cost and manufacturing driven optimization of composite part designs Structural part design Mechanical simula-on Material Scale Local Microstructure Performance density Manufacturing? 2

3 Stamping of composite prepregs Without blankholder With blankholder 3

4 Stamping of composite prepregs 4

5 Thermostamping of prepregs Influence of the stamping time Initial ply temperature : 290ºC Tool temperature :180ºC Stamping time : 1s Initial ply temperature : 290ºC Tool temperature :180ºC Stamping time : 10s Initial ply temperature : 290ºC Tool temperature :20ºC Stamping time : 1s Initial ply temperature : 290ºC Tool temperature :20ºC Stamping time : 2s 5

6 Thermostamping of prepregs + overmolding of LFTs 6 6

7 Injection/compression 7

8 Injection/compression Injection unit Mold heated by induction Hot runner Hot runner Upper part of the press Mold Cavity Bo8om part of the press Injec-on unit Injection from the bottom via the hot runner 8

9 Injection/compression # Vf [%] h [mm] Q [cm 3 /s] v [mm/s] ,5 Defects Fibre washing in the centre Bundle deformation at the borders Over-compaction in the middle

10 Compression of SMC [3DTimon] 10

11 11 Compression of SMC

12 Compression of SMC Fiber Representative volume element Homogeneous equivalent medium Part scale p p (orientation of a fiber) Thousands of fibers Ψ (probability distribu-on func-on) Ψ(x) a(x) a (orienta-on tensor) 12 12

13 Compression of SMC First step : Loading of the charge Second step : Compression of the charge : flow of the charge after 2 seconds Second step : computation of velocities and fiber orientations 13 13

14 Compression of SMC Through-thickness fiber orientation after 2s 14

15 Cost and manufacturing driven optimization of composite part designs 15

16 Cost and manufacturing driven optimization of composite part designs Structural part design Mechanical simula-on Material Scale Local Microstructure Process design Process simula-on 16

17 Process enhanced composite part optimization 17

18 Process enhanced composite part optimization 18

19 Process enhanced composite part optimization Optimization objectives q Full optimization cycle: q Design space definition q Topology optimization q Stacking sequence optimization on a final geometry q Stacking sequence optimization: q 7 zones with distinct UD ply lay-ups q The whole part can be enclosed by an isotropic chopped fiber material q Process: RTM injection with an injection line q Two optimization scenarios: q Without any manufacturing consideration q Using the RTM Process Estimator 19

20 Process enhanced composite part optimization q Different stacking sequences for every zone Without process considera9ons Using the RTM Process Es9mator Chopped fiber ply No Yes Differences Part Mass g g < 2% RTM filling -me 9.2 s 1.2 s 84% q RTM fill patterns Zones of flow weld lines Fill pattern without process consideration Resin injection line Resin injection line Fill pattern using the RTM Process Estimator 20

21 Computational framework Thermo-stamping Development of rapid process simulation models Overmolding SMC Process simulation with advanced rheological and flow models Multiphysics problem Multiply simulation considering thermal effects Process combination possible Fluid Flow Displacement Forces Temperature Solid mechanics Temperature Heat Transfer Deformation Deformation Complex flow models Meshless methods Compression molding Temperature Interface Liquid Solid Solid Liquid Interface Hydraulic press Press force speed Process comparisons: SMC, RTM, F3P Grade of automation Advanced process simulation, virtual material A characterization and optimization of composite parts Introduction of the Process Estimators Rapid manufacturability prediction Mould Macrostructure: Darcy Material class Material library Machine class Machine library Workforce class Workforce library Composite part Part class Production cost Material cost Preparation stage Process stage Finishing stage MAIN PROGRAM Variables: Automation grade Manufacturing volume Cost of the fiber Composite part cost prediction Outputs Combination Composite part optimization Combination Microstructure: Stokes Mesostructure: Brinkman Replace tensile and compression tests Virtual material characterization Ecole Centrale de Nantes / GeM 21