Light Weight Design of Al-Mg Hybrid Space Frames for Urban E-Vehicles Christian M. Chimani, Matthias Hartmann, Peter Simon, Martin Roschitz, Ziad Khalil, AIT Austrian Institute of Technology 03.11.2011
Contents General Company Information Vehicle Design Vehicle Design Details FE Simulation Conclusion and Outlook
General Company Information LKR Number of employees: 34 Location: Ranshofen, Austria Turnover: about 5 million euros 100% subsidiary of the AIT Non-university research establishment Certificates ISO 9001:2008 ÖNORM EN ISO/IEC 17025 Blin dtext auf einer PPT-Folie, ein Text without Ranshofen weitere Bedeutung, allein Vienna der Visualisierung LKR eines grafischen AIT Konzeptesdienend. (16pt) Seibersdorf Blindtext auf einer PPT-Folie, ein Text without weitere Bedeutung, allein der Visualisierung dienend.
Vehicle Design I Build up from Standard aluminium profiles (6060 T6) Extruded magnesium profiles (AZ 31) Casted aluminium joints (AlSi 7) Casted magnesium joints (AZ31) Aluminium sheet metal Machined aluminium parts
Vehicle Design II Mass distribution Mass space frame 130kg Overall mass for running chassis 570kg Component Simulated Mass: 800kg Battery, range extender Frame, Seats, Steering, Wheels Engine, Gearbox El. Parts, Cables, Bolts etc. Mass 210kg 238kg 47kg Ca. 75kg
Vehicle Design Details I Distance bushing For joining higher loaded parts, e.g. Suspension Seat belt anchor Pre-drilled holes Bushing welded into the holes Grinding of the welding seam
Vehicle Design Details II Connection of Al and Mg parts No welding procedure to secure stability Combination of baseplate and glue Roll forming of Mg roof beams Connection Aluminium to Magnesium 03.11.2011
FE Model I General Modelling 1.159.539 nodes 1.075.638 shell elements 108.393 solid elements 142 contacts
FE Simulation I Boundary conditions Euro NCAP frontal collision 64km/h 40% Offset
FE Simulation II Damage models in LS-Dyna CrachFEM (failure model) Plasticity with Damage (von Mises plasticity) DAMAGE_2 (continuum damage mechanics CDM) SAMP GTN GISSMO Failure or damage model can be implemented optionally to different elasto-plastic material models (e.g. von Mises plasticity, Hill`48, Barlat`89, YLD2000, ) Parameter determination directly from experiments
FE Simulation III GISSMO Generalized Incremental Stress State dependent damage MOdel Development of DAIMLER AG & Dynamore Aim is the linkage of forming simulation (yield locus, thinning) with crashsimulation (energy absorption, failure) different material models in each process Quelle: Neukamm, Haufe, Feucht; 7th Eur. LS-Dyna Conference 2009
FE Simulation IV Results - Structural deformation During whole simulation no exterior penetration of cabin Structural deformation only during first three steps (75ms) After ca. 75ms vehicle turns around barrier Safety potential left
FE Simulation V Results - Seat cross member Max. deceleration 35-40g Returns to zero after ~95ms Linear decline to zero Negative velocity (rebound) after ~90ms
Conclusion and Outlook I L7e vehicle designed for Euro NCAP scenario Realization as running chassis mostly build up from standard profiles Cabin withstands load of frontal impact with 64km/h Acceleration within the limits for good crashworthiness
Conclusion and Outlook II Weight optimisation possible by using more different profile cross sections Implement more functions to casted joints Lower part of A-pillar Door hinge Body panels
Acknowledgement Financing Involved partners
Danke für Ihre Aufmerksamkeit 03.11.2011