Modélisation du comportement anisotropique des matériaux thermoplastiques renforcés fibres de verre

Transcription

1 Modélisation du comportement anisotropique des matériaux thermoplastiques renforcés fibres de verre Sulmoni Mattia The information provided herein corresponds to our knowledge on the subject at the date of its publication. This information may be subject to revision as new knowledge and experience becomes available. The data provided fall within the normal range of product properties and relate only to the specific material designated; these data may not be valid for such material used in combination with any other materials or additives or in any process, unless expressly indicated otherwise. The data provided should not be used to establish specification limits or used alone as the basis of design; they are not intended to substitute for any testing you may need to conduct to determine for yourself the suitability of a specific material for your particular purposes. Since DuPont cannot anticipate all variations in actual end-use conditions DuPont makes no warranties and assumes no liability in connection with any use of this information. Nothing in this publication is to be considered as a license to operate under or a recommendation to infringe any patent rights. Copyright 2016 DuPont. All rights reserved. The DuPont Oval, DuPont, The miracles of science and all products denoted with or are registered trademarks or trademarks of E. I. du Pont de Nemours and Company or its affiliates.

2 DuPont: Innovation starts here $9.8B $5.3B $3.5B Agriculture Performance Materials Safety & Protection $3.3B $2.1B $1.2B Nutrition & Health Electronics & Communications Industrial Biosciences 2

3 From ART to PART - Application development Material data generation, R&D, physical & analytical lab, assembly Design Conceptual & creative design, material modeling, mechanical & rheological simulations Processing Injection molding, blow molding, extrusion Global Technical Capabilities for your applications Picture: courtesy Daimler/ElringKlinger Pictures: courtesy of BABYZEN Pictures: courtesy of BMW/Mann+Hummel Investing in application development since the 80s 3

4 Advanced Material Modeling for GR resins Material stiffness and strength are driven by the fiber orientation and the injection molding process Ultimate strain and strength are also influenced by the weld lines To correctly model the component response to high loads, anisotropic properties with accurate failure prediction must be considered in the FEA model 4

5 GR materials show anisotropic behavior Fibers highly oriented in the loading direction Orientation level ~0.9 (90% in flow) Fibers mainly oriented in the loading direction Orientation level ~0.75 (75% in flow) E= E=5 300 MPa MPa E= MPa E=3 000 MPa Fibers mainly oriented perpendicular to the loading direction Orientation level ~0.3 (30% in flow) E=1 500 E= MPa MPa 50% C 5

6 GR materials show anisotropic behavior Experimentally measured fiber orientation via 3D tomography: 3D Tomography Skin Core 6

7 GR materials show anisotropic behavior Orientation Orientation Real test: 2.4 mm Real 23 C Real test: 3.2 mm 7

8 How to simulate GR material behavior? Orthotropic Major assumptions Isotropic Approach Mechanical properties identical in all the directions: Orthotropic Approach Mechanical properties specified in 3 perpendicular planes: Close to reality Anisotropic Approach Mechanical properties change with direction along the object: One representative curve leading to wrong property estimations Rigid rotation approximation not always valid Most accurate but complicated modeling + CPU 8

9 Anisotropic material modeling Directly in Ansys: Or via external software: Material modeling software Based on Micro-mechanics Plug-in to all structural FEA codes 9

10 How Digimat works From per-phase properties + microstructure definition (local orientation / GR content / AR / ) Digimat computes properties at any orientation state: 10

11 Coupled analysis with Digimat Digimat computed material properties are then used in a coupled FEA analysis: Digimat material card Moldflow orientation FEA analysis FEA analysis coupled with Digimat needs: FEA model Digimat material card Fiber orientation Each element has unique property based on local orientation and loading direction Different ways to link Digimat to Ansys (micro, hybrid,..) 11

12 Advanced Material Modeling - Workflow in-house material testing Material modeling in Digimat Applied to real structures Material validation in Ansys 12

13 Plastic Engine Brackets Engine bracket: component supporting the engine weight and vibrations 2 different designs, one per side Metal replacement - challenges : - High loads and T: above 1.5 tonnes and 130 C (+aging) - Static and dynamic loading in 3 different directions - Limited spacing and design freedom Advanced Simulation Isotropic simulation Test Need of advanced simulation methodology to correctly predict the part behaviour + failure and finally propose accurate design modifications

14 Quasi static modeling Engine Bracket bolts L o a d ISOTROPIC ANISOTROPIC bushing 14

15 FEA Modeling - ISO vs. ANISO - displacements ISOTROPIC ANISOTROPIC Higher deformations Max. displacement: 6.7 mm Max. displacement: 20.5 mm [mm] [mm] CPU timing (local 64 Gb PC) : Ansys ~X Mapping ~20 min + Moldflow ~30 min In

16 FEA Modeling - ISO vs. ANISO - displacements ISOTROPIC ANISOTROPIC Test 16

17 FEA Modeling - ISO vs. ANISO failure criteria ISOTROPIC ANISOTROPIC 17

18 FEA Modeling - ISO vs. ANISO failure criteria ISOTROPIC ANISOTROPIC Path of crack Identical for the two material models 18

19 FEA Modeling - ISO vs. ANISO failure criteria ISOTROPIC ANISOTROPIC Clear differentiation Higher risk of failure detected 19

20 FEA Modeling - ISO vs. ANISO failure criteria ANISOTROPIC Failure Indicator is much higher for the anisotropic analysis (factor 2X vs. isotropic). Fibers are orientated perpendicular to the loading direction in that area and a weld line is present. That s why FI is much greater than isotropic. 20

21 Conclusion Anisotropic analysis provide better accuracy and correlation with reality Usage selection depends on the specific load cases and stage of the project Material modeling is complicated and has to be managed by experts FEA approach is identical but may need additional advanced expertise Digimat is now fully integrated in Ansys Ansys Mechanical / Workbench 21

22 The information provided herein corresponds to our knowledge on the subject at the date of its publication. This information may be subject to revision as new knowledge and experience becomes available. The data provided fall within the normal range of product properties and relate only to the specific material designated; these data may not be valid for such material used in combination with any other materials or additives or in any process, unless expressly indicated otherwise. The data provided should not be used to establish specification limits or used alone as the basis of design; they are not intended to substitute for any testing you may need to conduct to determine for yourself the suitability of a specific material for your particular purposes. Since DuPont cannot anticipate all variations in actual end-use conditions DuPont makes no warranties and assumes no liability in connection with any use of this information. Nothing in this publication is to be considered as a license to operate under or a recommendation to infringe any patent rights. Copyright 2016 DuPont. All rights reserved. The DuPont Oval, DuPont, The miracles of science and all products denoted with or are registered trademarks or trademarks of E. I. du Pont de Nemours and Company or its affiliates. 22