Optimierung von Kunststoffbauteilen im Crash: Status und Ausblick - PowerPoint PPT Presentation

Optimierung von Kunststoffbauteilen im Crash: Status und Ausblick Torsten Hensel – BASF SE Dr. Steffen Frik, Opel AG Andreas Wüst, BASF SE Dr. Stefan Glaser, BASF SE

Content  Motivation  Material modelling of Short fibre reinforced thermoplastics for Crash  ULTRASIM™ examples and applications at OPEL  Modelling Energy absorbing structures out of glass-filled thermoplastic materials  Vision  Integrative Approach  Summary Wüst, Frik, Hensel, Glaser LS-DYNA Forum 2011 - Filderstadt 2

Motivation Application of Polymers • More and more structural components are made of polymers (e.g. short fiber reinforced polymers) • These materials show significant anisotropy due to fiber orientation caused by injection molding • In order to predict component behavior, kinematics and structural response with required accuracy, anisotropy must be captured Wüst, Frik, Hensel, Glaser LS-DYNA Forum 2011 - Filderstadt 3

Lower Bumper Support Development targets: • Optimized, ribbed plastic structure to provide sufficient support for lower leg during the impact • Needs to fail in a controlled manner during RCAR impacts in order not to damage other components • Low weight at reasonable costs Wüst, Frik, Hensel, Glaser LS-DYNA Forum 2011 - Filderstadt 4

Lower Leg Impact Kinematics Without Lower Bumper Support With Lower Bumper Support Support lower leg, No support of lower leg reduce knee bending angle Wüst, Frik, Hensel, Glaser LS-DYNA Forum 2011 - Filderstadt 5

6 LS-DYNA Forum 2011 - Filderstadt Lower Leg Impact (Full Model) Wüst, Frik, Hensel, Glaser

Simulation Results Impact on stiffness and rupture Normalized acceleration 7 Wüst, Frik, Hensel, Glaser LS-DYNA Forum 2011 - Filderstadt

Integrative Simulation ULTRASIM™ for fiber reinforced thermoplastics Process Measurement BASF Material model • Anisotropic • Nonlinear Part • Strain-rate sensitive • Tension-compression asymmetric • Failure modelling • Temperature dependent Wüst, Frik, Hensel, Glaser LS-DYNA Forum 2011 - Filderstadt 8

Integrative Simulation ULTRASIM™ Fiber orientation and material behaviour Calculated glass fiber orientation based Stress on optimum processing conditions Fiber orientation of 0,5 Local true stress strain at a fiber orientations of 0.5 Orientation of fibers Strain Stress Stress Fiber orientation of 0,7 Fiber orientation of 0,9 Local true stress strain at a Local true stress strain at a fiber orientations of 0.7 and 0.3 fiber orientations of 0.9 and 0.1 Strain Strain Wüst, Frik, Hensel, Glaser LS-DYNA Forum 2011 - Filderstadt 9

Integrative Simulation ULTRASIM™ Data flow structure ABAQUS, LS-Dyna, PAM, RADIOSS, NASTRAN Geometry, Boundary Finite Element Simulation Cond. MOLDFLOW FIBER anisotropic material model MOLDEX    homogenization of p Filling- orientation simulation homogenization of fibers Material- parameter and polymer Material model Material model Material- for fibers parameter for polymer •elastic •elastic •lastic-plastic •brittle •viscoplastic Wüst, Frik, Hensel, Glaser LS-DYNA Forum 2011 - Filderstadt 10

LBS Implementations 2006 2008 2009 2010 Wüst, Frik, Hensel, Glaser LS-DYNA Forum 2011 - Filderstadt 11

Additional Applications  Engine Mounts (e.g. Insignia)  Special Seats (e.g. Insignia OPC) Wüst, Frik, Hensel, Glaser LS-DYNA Forum 2011 - Filderstadt 12

Stress-Strain behaviour Tension-Compression Asymmetry influence: fiber orientation Injection moulded plate and hydrostatic stress state Stress [MPa] Compression 120 100 Tension 80 60 Tension Compression 40 20 0 Strain [%] 0 2 4 6 8 9 10 Wüst, Frik, Hensel, Glaser LS-DYNA Forum 2011 - Filderstadt 13

Example for an Energy absorbing plastics structure – BASF Test Specimen for compression load Needed for Calibrating Failure Simulation Parameters Specimen is designed for controlled collapse Material: B3WG6 CR (PA6 GF30%) sliding barrier 60 mm 60 mm Wüst, Frik, Hensel, Glaser LS-DYNA Forum 2011 - Filderstadt 14

Plastic specimen under compression load Simulation and Experiment Wüst, Frik, Hensel, Glaser LS-DYNA Forum 2011 - Filderstadt

Test-specimen under compression load Simulation and Experiment 60 mm Wüst, Frik, Hensel, Glaser LS-DYNA Forum 2011 - Filderstadt 16

Lower Loadpath Traditional Metal Crashbox: Loadpath 1 Space for additional New Loadpath 2 Absorber Wüst, Frik, Hensel, Glaser LS-DYNA Forum 2011 - Filderstadt 17

Videocomparison Absorber  enhanced ULTRASIM™ failure modelling ULTRASIM™ Integrative Math. Simulation Optimierung Wüst, Frik, Hensel, Glaser LS-DYNA Forum 2011 - Filderstadt

Dynamic Test Video Drop mass: 60 kg Drop height: 2.5 m Drop Energy: 1.47 kJ  25 msec Duration:  75 mm Displacement: Part weight: ~130gr Wüst, Frik, Hensel, Glaser LS-DYNA Forum 2011 - Filderstadt

Parameter Optimization in CAE Iterative process based on mathematical optimization methods Design Variables Mathematical FE-Solver Optimization Methods System responses Design parameters • Wallthickness • Contours • Rib heights • … Wüst, Frik, Hensel, Glaser LS-DYNA Forum 2011 - Filderstadt

Shape Optimization using Morphing Morphing parameter 1 Morphing parameter 2 Wüst, Frik, Hensel, Glaser LS-DYNA Forum 2011 - Filderstadt

Vision – Integrative Optimization Standard Optimization and Integrative Approach Plastics granulate with Injection Part Assembly Product in use glass fibers molding process BASF ULTRASIM • Crash • Static Loads • NVH • Warpage • … Standard Approach Integrative Optimization Approach Wüst, Frik, Hensel, Glaser LS-DYNA Forum 2011 - Filderstadt 22

Workflow for Standard Optimization Approach   x   1 Mathematical System parameters Vector of Design   x e.g. wallthicknesses Optimizer 2 Variables     x 3 Modified FE-Inputfile vector of Responses   FE-Solver r   1 ABAQUS, LS-Dyna, PAM   r 2     r 3 FE-Results Response Extraction Wüst, Frik, Hensel, Glaser LS-DYNA Forum 2011 - Filderstadt 23

Workflow for Integrative Optimization Approach Single disciplinary (without morphing)   x   1 Mathematical General system parameters Vector of Design   x Optimizer 2 Variables     x 3 Wallthickness, Injection time and location, temperatures, gate delay times, … Wallthickness, … vector of Intermediate Mesh Responses for mapping   r   1 Discipline „ 0 “ : Discipline 1:   BASF ULTRASIM ™ Process r 2 Mechanical FE Fiber Orientation   Simulation Mapping Simulation   r Manufacturing 3 Wüst, Frik, Hensel, Glaser LS-DYNA Forum 2011 - Filderstadt 24

Workflow for Integrative Optimization Approach Multi disciplinary (with morphing)   x   1 Mathematical General system parameters Vector of Design   x Optimizer 2 Variables   Morphing   x 3 Wallthickness, Injection time and location, temperatures, gate delay times, … vector of Responses   r   1 Intermediate Intermediate Intermediate Process Mesh Mesh Mesh   BASF ULTRASIM ™ r 2 Fiber Orientation Simulation   Mapping   Manufacturing r 3 Discipline „ 0 “ Discipline 1 Discipline 2 … Discipline n Wüst, Frik, Hensel, Glaser LS-DYNA Forum 2011 - Filderstadt 25

Integrative Optimization Example Filling, Warpage, Impact, Static Load, Shape Optimization by Morphing LS-OPT, MOLDFLOW, LS-Dyna, ANSA, ABAQUS Filling Warpage Integrative Morphing Optimization Static Load Impact Wüst, Frik, Hensel, Glaser LS-DYNA Forum 2011 - Filderstadt

Summary  More and more structural vehicle parts are made of anisotropic polymers  Injection molding process determines fiber orientation and thus local mechanical properties  ULTRASIM TM approach has been applied for numerous applications  Initially: Lower bumper support for pedestrian protection  Extended to engine mounts and seats  Simulation results show excellent correlation with physical tests  Extended ULTRASIM™ failure model is crucial for the accurate design of energy absorbing structures  Integrative Optimization Approach allows simultaneous optimization of process and mechanical characteristics Wüst, Frik, Hensel, Glaser LS-DYNA Forum 2011 - Filderstadt 27