3 rd EUROPEAN HTC 2009 Technische Simulation GmbH Vision: Global Leader in Computer Aided Engineering (CAE) FORD R&D project: advanced laminated glass modeling for safety FEA using RADIOSS Mark Gevers (General Manager, GmbH) Robert Schilling (Technical Specialist, FORD Werke GmbH) 1
Contents Improve predictability of glass model Targets RADIOSS shell formulations mesh influence : windshield in vehicle assembly head impact in mid area in cowl area roof crush influence parameters on laminated glass model 2
Business Area: is Europe s largest, independent service provider in Computer Aided Engineering (CAE) the computer-based development and optimization of components, structures, and products Markets: Original Equipment Manufacturers (OEMs) and suppliers in automotive, chemical, aerospace, medical, and consumer good industries Turnover: 2008: 20,2 Mio Euro 2007: 18 Mio Euro 2006: 12 Mio Euro Foundation: 1992 Employees: 2008: 240 Employees 2007: 210 Employees 2006: 150 Employees Vision: Global Leader in Computer Aided Engineering 3
Ruesselsheim (Headquarters) Cologne Munich Stuttgart Wolfsburg (Branch) (Branch) (Branch) (Branch) Bangalore Basildon Saitama/Tokyo (Branch India) (Branch UK) (Branch Japan) 4
References (Selection) Adam OPEL Autoliv Karmann AUDI BMW Benteler Bombardier Keiper Kirchhoff Daihatsu Daimler Bosch Brose Lear Magna Group FIAT CR Hammerstein MAN FORD GM Daewoo DLR Dura Automotive MBTech Montaplast Honda Hyundai/Kia Dynamit Nobel Deutz Plastal Perkins Isuzu EADS Recaro Jaguar Land Rover Fendt Georg Fischer Siemens VDO Siemens Power Generation Nissan Getrag FORD Transmissions Takata-Petri Porsche Getrag TRW Renault Faurecia ThyssenKrupp Toyota Hella Visteon Volkswagen HBPO Wagon Automotive IAC ZF-Sachs Johnson Controls etc 5
Vehicle CAE HS/LS-Crash CAE Consulting CAE-Processes Advanced CAE New Vehicle Concepts Dynamics/NVH Product Optimisation CAE-Material Validation Stability/Durability Acoustics CFD/Aerodynamics Software/Hardware Training Barrier Development CAE Process Chain Seats CAE CAE Products Powertrain CAE ECE-xx TEC BENCH TM Dynamics/NVH Dynamics Stability TEC ODM TM TEC PROM TM Stability/Durability CFD/UTM TEC WORX TM Acoustics Interior CAE Occupant Protection Subsystems CAE Stability/Durability Chassis CAE Dynamics/NVH Restraint Systems Dynamics/NVH Stability/Durability Pedestrian Protection Structural Optimisation Impact Simulation CFD/HVAC Interior Concepts DOE Crash Driveover Curb MKS/MKS-Structure Coupling CFD 6
Improve predictability Targets : improve predictability of glass model Regarding pedestrian protection the head impact on the windscreen of a car is focused by several legal requirements and many consumer tests (NCAP) all over the world 7
Improve predictability Targets : improve predictability of glass model For a predictive finite element analysis a improved laminated glass model of the windscreen is needed This investigation for FORD improves the CAE modeling technique for laminated glass under impact load cases using Altair s explicit solver RADIOSS 8
Improve predictability Targets : improve predictability of glass model Because of respecting physical laminated glass properties the advanced RADIOSS model also improves the behavior of the windscreen under quasi-static roof crush load case 9
Improve predictability Targets : targets Improve laminated glass RADIOSS model for windshield modeling to get better test correlation Respect glass failure Use shell mesh only change material an properties One windshield model for all load cases 10
: RADIOSS shell formulations Target: use shell mesh only update material and properties: RADIOSS multi layered shell should be used to improve laminated glass model RADIOSS shell form mesh influence In RADIOSS 44 there was some confusion regarding layered rupture of the multi layered shell Since RADIOSS 51 these issues are solved 11
: mesh influence Classical elasto-plastic model with regular quad mesh RADIOSS shell form mesh influence 12
: mesh influence Improved laminated glass model respecting rupture with regular tria mesh RADIOSS shell form mesh influence 13
: mesh influence Improved laminated glass model respecting rupture with impact depending mesh RADIOSS shell form mesh influence 14
: mesh influence Best visual results with circular tria mesh around impact point RADIOSS shell form mesh influence The mesh was generated using HyperMesh, controlled by TEC WORX automation technology 15
: windshield in vehicle assembly head impact Component models windshield in vehicle head imp in mid area head imp in cowl area roof crush FORD Mondeo FORD Galaxy 16
: windshield in vehicle assembly head impact mesh size mesh type glass properties 672%!"#$% &"'#()*% After varios investigation on PVB-layer properties windshield in vehicle head imp in mid area head imp in cowl area roof crush number of integration points over thickness we found a highly improved model behavior compared to current state-of-the-art modeling technique 2345-*"/% +/0+"/1"#% ('8"#1,10'%,-##% +/0+"/1"#%!"#$% )*+"% 17
: head impact in mid area windshield in vehicle head imp in mid area head imp in cowl area roof crush 18
windshield in vehicle head imp in mid area head imp in cowl area roof crush : head impact in mid area Normalized head form acceleration 100 % 80 % 60 % 40 % 20 % 0 % old model improved model 0 1 2 3 4 5 6 7 8 9 10 Time [ms] High influence of glass rupture stress on first head form acceleration Influence of glass rupture stress on after first peak area is less Influence of PVB stiffness is less Influence of mesh technique is less: regular tria mesh usable test 19
: head impact in cowl area windshield in vehicle head imp in mid area head imp in cowl area roof crush 20
: head impact in cowl area Rupture behavior: windshield in vehicle head imp in mid area head imp in cowl area roof crush Fine tria circular mesh Coarse tria mesh Test 21
: head impact in cowl area windshield in vehicle head imp in mid area head imp in cowl area roof crush 22
: head impact in cowl area Rupture behavior: windshield in vehicle head imp in mid area head imp in cowl area roof crush Fine tria circular mesh Coarse tria mesh Test Influence of non-physical rupture direction to head form acceleration is less Regular impact independent mesh respecting full vehicle time step is usable Rupture area in test is bigger than in simulation Non-physical behavior of glass-adhesive found further improvement needed 23
: windshield in vehicle assembly roof crush windshield in vehicle head imp in mid area head imp in cowl area roof crush FORD Mondeo 24
: roof crush windshield in vehicle head imp in mid area head imp in cowl area roof crush 25
: roof crush Influence of rupture is less Coarse regular mesh is usable 120 % test old model improved model windshield in vehicle head imp in mid area head imp in cowl area roof crush Normalized reaction force 100 % 80 % 60 % 40 % 20 % 0 % 0 1 2 3 4Intrusion 5 6 7 8 9 10 glass rupture 26
Advanced laminated glass modeling technique for RADIOSS gives high improvements in head form impact simulation for different impact points (mid area and edge area) compared with current FORD model Modeling technique with multi layered shell respecting laminated glass layers (glass-pvb-glass) works with physical material properties (no tuning needed) Behavior after first breakage should be improved in further investigation PVB influence seems to be less for model used in this investigation Fulfilling full vehicle time step is possible The improved model has also a positive impact on roof crush load case The addition of model-setup and simulation time is less 27
To improve the laminated glass behavior after first breakage a deeper understanding of pre-stress resulting from production process and assembly is needed Pre-stress situation: t glass PVB glass σ 28
influence parameters To improve the laminated glass behavior after first breakage a deeper understanding of pre-stress resulting from production process and assembly is needed Mapping of pre-stress data to the different integration points over the shell thickness must be possible for the laminated shell property Using shell elements might not be sufficient because pre-stress is a non-thin phenomena Respecting difference rupture strain of glass in traction and compression direction PVB behavior is not properly definable in RADIOSS material models but influence seems to be less Respecting physical properties and understanding physical phenomena will result in further improvement of glass model with a highly predictive behavior for all load cases 29
influence parameters : influence parameters on laminated glass model Normalized head form acceleration 100 % 80 % 60 % 40 % 20 % 0 % Mesh influence and glass rupture criteria Scalable via glass rupture criteria Scalable via meshing technique Influence of pre-stress situation and PVB layer properties Time [ms] test old model improved model Scalable via pre-stress and/or PVB properties 0 1 2 3 4 5 6 7 8 9 10 30
: influence parameters on laminated glass model influence parameters For further improvements a study on all influence parameters using statistical analysis will be helpful will investigate on improved laminated glass model via a funded research project in deep cooperation with FORD 31
Contact Technische Simulation GmbH Mark Gevers General Manager Robert-Bosch-Str 10 D-50769 Cologne Germany Phone +49 221 56949 411 Fax +49 221 56949 449 Mail mgevers@detecosimcom wwwtecosimcom 32
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