Topology Optimization of a Steel-Aluminium-Hybrid for an Automotive Body Structure

Transcription

1 Altair EHTC Topology Optimization of a Steel-Aluminium-Hybrid for an Automotive Body Structure Speaker: D. unke (Imperia GmbH) November 4th, 2009 Ludwigsburg

2 Agenda 1. Common Hybrid Structures in today s Automotive Industry 2. The Steel-Aluminium-Hybrid: VarioStruct 3. Principle of Hybrid Structures 4. Loadcases 5. Dimensioning of the Sheet Metal Profile 6. Analogous Model for Rib Optimization 7. Dimensioning of Rib Structure with Submodel 8. Dimensioning of Rib Structure with Component Model 9. The VarioStruct Roof Crossmember 10. Mechanical Properties of the VarioStruct Roof Crossmember Page 2

3 1. Common Hybrid Structures in today s Automotive Industry Application of metal-plastic-hybrid in an automotive body Steel-lightmetal-composite casting in motor manufacture Source: Lanxess Source: Honda Roof crossmember with masterformed plastic reinforcement orm closure Engine block with cast-in cylinder liners orm closure Metallic continuity Page 3 Thin-walled steel-lightmetal-hybrids for automotive body structures

4 2. The Steel-Aluminium-Hybrid: VarioStruct Material 1 (Sheet) property profile 1 + Material 2 (Cast) property profile 2 master forming Steel-Aluminium- Hybrid metallic continuity frictional connection Aluminium rib structure casted in steel sheet profile Advantage of both material will be taken Connection steel casting Complex cast structures with sheetmetals possible form closure continued sheet metal cast cantilever assembly attachment Page 4 High potential of integration Possible to combine other materials extrusion joint

5 3. Principle of Hybrid Structures supporting effect Conventional sheet metal structure cross section height Conventional sheet metal structure Hybrid structure Hybrid structure Prevention of local buckling Limitation of plastic hinges less weight higher energyabsorption cross section height Page 5 Maximum supporting effect: Optimal dimensioning of cast ribs Design proposal: topology optimization with OptiStruct

6 4. Loadcases Example of Submodel Component Model Roof impact Design space 3-point-bending, centric Pole impact 3-point-bending, excentric Torsion Axial compression Page 6 Combination of all loadcases Combination of all loadcases

7 5. Dimensioning of the Sheetmetal Profile Topology optimization (solids) Submodel Combination of all loadcases Result of topology optimization Derived profile of sheetmetal Page 7 Next step: dimensioning of rib structure

8 6. Analogous Model for Rib Optimization Application of volume elements Elements, calculation time Maximum rib thickness element size (Maxdim = 6 * l c ) Remedial action with approach by Hartzheim [1] Design space: shell elements Approximation of volume: rigid bars Elements High resolution with small elements thin ribs shell layer 1, design space rigid bar shell layer 2, sheetmetal, nondesign space Page 8 [1] HARTZHEIM, Lothar: Strukturoptimierung, Verlag Harri Deutsch, rankfurt, 2008

9 7. Dimensioning of Rib Structure with Submodel design space Iteration 10 Topology optimization (shells) Iteration 20 Submodel Combination of all loadcases Suitable for outer rib structures Iteration 30 derived structure Page 9 Next step: dimensioning of rib structure in crossmember s middle area

10 8. Dimensioning of Rib Structure with Component Model ribs derived from first optimization design space Iteration 15 Iteration 25 Topology optimization (shells) Component model Combination of all loadcases Suitable for inner rib structures Iteration 36 Page 10 Next step: derive initial rib structure for nonlinear optimization

11 9. The VarioStruct Roof Crossmember loadcases, constrains, designspace,... topology optimization, solids topology optimization, shells component model submodel derive rib structure initial design nonlinear optimization (crash loadcases) Page 11 final design

12 10. Mechanical Properties of the VarioStruct Roof Crossmember Hybrid structure Page 12 Conventional sheetmetal structure

13 11. Mechanical Properties of the VarioStruct Roof Crossmember 3-point-bending test orce [-] Conventional Original VarioStruct Displacement [mm] 120% 100% 80% 60% 40% 20% 0% 75% 106% 112% Mass Maximum orce Absorbed Energy Page 13

14 Thanks to BMB Thanks to project partners Thanks for support in research project from Page 14

15 Thank you for your attention! Imperia GmbH Automotive Engineering Soerser Weg 9 D Aachen Page 15 Dipl.-Ing. (H) David unke Tel.: (0) ax: (0) Mail: funke@imperia.info Dipl.-Ing. Niels Nowack Tel.: (0) ax: (0) Mail: nowack@imperia.info