Technische Universität München
New Approaches for Shape & Topology Optimization for Crashworthiness keynote lecture
Prof. Dr. Fabian Duddeck Technische Universität München Germany [email protected] Technische Universität München
Acknowledgements
My PhD students: S. Hunkeler, M. Rayamajhi, A. Berger Queen Mary University of London (QMUL) K. Volz, T. Dietrich, J. Fender Technische Universität München (TUM) C. Ortmann TUM in collaboration with HAW Hamburg My research partners K.-U. Bletzinger and his team from the TUM H. Zimmer, M. Prabhuwaingankar, and the team of SFE GmbH L. Rota, M. Zarroug (PSA Peugeot-Citroen) A. Schumacher (HAW Hamburg) and E. Schelkle (ASC-S) H. Müllerschön (DYNAmore GmbH) F. Dirschmid, G. Fichtinger, O. Meyer, A. Übelacker, M. Zimmermann (BMW) J. Will (DYNARDO GmbH) T. Pyttel (ESI GmbH & FH Gießen-Friedberg)
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Outline
1. New Challenges 2. State-of-the-Art in Shape & Topology Optimization for Crashworthiness 3. New Approaches for Shape & Topology Optimization for Crashworthiness 4. Conclusions
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Outline
1. New Challenges 2. State-of-the-Art in Shape & Topology Optimization for Crashworthiness 3. New Approaches for Shape & Topology Optimization for Crashworthiness 4. Conclusions
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New Challenges: New Structural Concepts!
Aixam Mega BMW Bolloré/Pininfarina BYD Daimler Mega E-City E-mini Blue Car E6 Smart ed
General Motors Heuliez Mitsubishi Nissan Reva Volt Will i-Miev E-Cube G-Wiz
???
Subaru Tesla Motors Th!nk Volkswagen R1e Roadster City Twin Drive
ETC/ACC Technical Paper 2009/4 Electric Cars F. Hacker, R. Harthan, F. Matthes, W. Zimmer
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New Challenges: New Structural Concepts!
www.loremo.com
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New Challenges: Electromobility
www.mute-automobile.de www.llb.mw.tum.de
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New Challenges: Electromobility
www.mute-automobile.de www.llb.mw.tum.de
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New Challenges: New Materials (CFRP)
www.bmw-i.de
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Lightweight Design (e.g. SuperLightCar EU Project)
SP1 Design Concepts SLC Body Concept
1) Steel intensive < 2,5 €/kg
2) Multi material, economic (ULBC) < 5 €/kg
3) Multi material, advanced (SLBC) < 10 €/kg
SP2 Materials & Manufacturing Technologies SP4 End of 2008 Technology-Benchmarking Complete Multi-Material Forming Body structure Joining Prototype Assembly Demonstration
SP3 Simulation & Testing Life Cycle Analysis (LCA) ■ Cost assessment ■ Virtual and physical Testing
2005 2006 2007 2008 2009
M. Stehlin, Volkswagen 2008
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New Approach: Integral Lightweight Design
Established: Multi-material, forming, joining assembly, life-cycle, etc.
SFE GmbH & Porsche SFE GmbH + Optimal Structure + Optimal Package & Design (Size, Shape & Topology) (New Concepts)
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Shape and Topology Optimization for Crash
Concept
Material Steel Aluminium Composites
Topology
Shape
Size (thickness)
Zimmer, Hänschke
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Topology Opt. for Crash (1): Ground Structure
Ground structure approach
Domain is meshed by beams.
• Design variables: size of cross-section areas
• Objectives: acceleration, displacement, compliance Pedersen (2004)
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Topology Opt. for Crash (1): Ground Structure
Rigid wall (sliding) Passenger cabin
Tire
Engine 75 kg Car mass 750 kg
• Implicit FEM • Analytic sensitivities • No contact, no inertia • Low generality in geometry Pedersen (2004)
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Topology Opt. for Crash (2): Equivalent Static Loads
Communal structure • Nonlinear crash cases Partly comm. structure represented by equivalent Topology variation linear static load cases Specific structure • Only beam elements and single masses • For optimisation: size variables dimensions of the cross-sections (gauge, height, width, orientation) Mass-beam model for size, shape • Shape variables: and topology optimisation Connection points of the beams
Torstenfelt B and Klarbring A (2007): Conceptual optimal design of modular car product families using simultaneous size, shape and topology optimization. Finite Elem. in Analysis & Design 43, 1050 – 1061.
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Shape Opt. for Crash (1): Morphing
Morphing boxes
Georgios 2009 Morphing can only realise small geometrical modifications a More flexible shape optimization methods required
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Shape Opt. for Crash (1): Beyond Morphing
© SFE GmbH 2011
SFE CONCEPT model SFE CONCEPT FE model
H. Zimmer, M. Prabhuwaingankar, F. Duddeck (2009): Topology & geometry based structure optimization using implicit parametric models and LSOPT. 7th Europ. LS-DYNA Conf., Salzburg, Austria.
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Outline
1. New Challenges 2. State-of-the-Art in Shape & Topology Optimization for Crashworthiness 3. New Approaches for Shape & Topology Optimization for Crashworthiness 4. Conclusions
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Topology Opt. for Crash (3): Hybrid Cellular Automata
Initial design
Crash analysis x(k+1) U(x(k))
Update material distribution using HCA rule Δx = f(U,U*)
x(k+1) = x(k)+Δx
Convergence test no
yes
Final design
A Tovar & JE Renaud (2008): Altair HyperWorks Symposium
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Topology Opt. for Crash (3): Hybrid Cellular Automata
Linear-static
v 0=40 m/s Nonlinear 5 x 10 static 16 linear nonlinear 14 dynamic
12
10 Nonlinear 8 dynamic
6
4
2
0 0 50 100 150 200 A Tovar & JE Renaud (2008): Altair HyperWorks Symposium
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Topology Opt. for Crash (3): Hybrid Cellular Automata
Hunkeler (PhD thesis), Duddeck (QMUL)
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Topology Opt. for Crash (4): Graph-based Method
• Setup of different designs with „library parts“, e.g. beams, panels • Each library part has a representation as an attributed mathematical (sub-)graph • Library parts can be connected to make up structures • Topological changes are applied as changes to the design graph • Graph based topology optimization is understood as optimization of the design graph topology • Shape optimization is applied in an inner loop in each topological iteration
A Schumacher & C Ortmann (2011): CARHS Automotive Grand Challenge
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Topology Opt. for Crash (4): Graph-based Method
A Schumacher & C Ortmann (2011): CARHS Automotive Grand Challenge
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Topology Opt. for Crash (4): Graph-based Method
triangular panel
beam
coordinate vertex and structural link
quadrangular panel
A Schumacher & C Ortmann (2011): CARHS Automotive Grand Challenge
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Technische Universität München Parametric models revolutionize the VPD
SFE CONCEPT for Shape and Topology Optimization
SFE CONCEPT Parametric Model
Points and Lines
Cross Sections
Joints & Beams
Freeform Surfaces
Beads, Stamps, Ribs
FE Meshes
Welds, Adhesives
Loading, Etc.
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Technische Universität München Parametric models revolutionize the VPD
SFE CONCEPT for Shape and Topology Optimization
May-11 Duddeck 26 SFE CONCEPT: Data Flow Challenges in optimization Technische Universität München Parametric models revolutionize the VPD
Parameterization for Optimization (Two Types)
Maintaining geometrical and Maintaining geometrical and topological compatibility is topological compatibility is nearly impossible automatic and very easy
Explicit parameterization Implicit parameterization (CAD) (SFE CONCEPT)
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Parameterization for Optimization (Two Types)
Without With surface map surface map
1.1)
1.1) 2.) ? 1.2)
Following information is lost: Automatically done: • Multi-flange assignment • Reparametrising the map-targets • Joining assignment • Identifying the flanges/joining
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Technische Universität München Parametric models revolutionize the VPD
Combined Shape and Topology Optimization
Script for model FE mesh & Batch update & FE boundary mode DV in mesh creation conditions ASCII format DV-file SFE CONCEPT FE mesh & Design Design Boundary Modified variables design variables in conditions variables optimizer format Problem definition (only done once) Design variables Optimization loop FE SOLVER Optimizer LS-DYNA, NASTRAN, (e.g. LS/OPT, in house) PAM-CRASH, PERMAS ASCII output Objective function RADIOSS, ABAQUS & constraints ASCII output
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Algorithmic Aspects
Hybrid and hierarchical methods for multi-level optimization
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Technische Universität München Parametric models revolutionize the VPD
Combined Shape and Topology Optimization
Topology Opt. Principle Load Paths
SFE CONCEPT Geometry Model Design Space Package Opt.
Shape & Topology changes
Refinements Optimization
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Topology Optimization for Crash (ESLM)
• Equivalent static load method Package Design space (ESLM) and standard topology optimization (linear FEM). • Equivalent loads are defined for Optimisation model different time steps based on energy considerations. • Result is embedded in an overall loop “topology – shape – size” optimization. Transfer to shape opt. • Result corresponds well to reference designs • New design alternatives can be Result (topol. opt.) identified K. Volz (PhD Dissertation) TU München & BMW (2011)
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Topology Optimization for Crash (ESLM)
First load phase Second load case Third load case
K. Volz (Dissertation) TU München & BMW (2011)
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Topology Optimization for Crash (ESLM)
K. Volz (Dissertation) TU München & BMW (2011)
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Combined Shape & Topology Opt. (SFE CONCEPT)
K. Volz (Dissertation) TU München & BMW (2011)
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Conclusions
1. New approaches for topology optimizaton (crash): • Equivalent Static Load Method (ESLM) • Hybrid Cellular Automata (HCA) • Graph-based method 2. New approaches for shape optimization (crash) • Implicit parameterization (SFE CONCEPT) • Direct parameterization (CAD-based) • Morphing, etc. 3. Combined package / material / structure (shape & topology) optimization required.
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End.
Automotive Trains
Shipping Front Radiator door support
Lift gate Offshore
Front sub-frame
Hood White goods Aerospace SFE GmbH
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Contact
Prof. Dr. Fabian DUDDECK FG Computational Mechanics Technische Universität München
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