Mass Reduction and Energy Absorption Maximization of Automotive Bumper Systems

Giorgio Buccilli, René Wohlgethan (Enginsoft)

CHALLENGE – The main goal of automotive bumpers is to absorb kinetic energy during plastic structural deformation in order to prevent occupant injury.  Typically, the more mass a bumper has, the more energy it can absorb. However, more mass also means more material, higher costs and poorer fuel efficiency.

SOLUTION – To analyze the bumper behavior and identify a solution that simultaneously improves absorption capability without increasing weight, engineers created the simulation models required for the analysis. CATIA was used to create the 3D geometry with Profile Depth, Crimping Depth and Radius considered as inputs; HYPERMESH was used to convert the CAD to an LS-DYNA mesh; LS-DYNA was used to run the crash simulation with varying inputs being the Bumper Sheet Thickness and Closing Sheet Thickness. The design simulation process was successfully automated, enabling effective process automation while the MOGA-II algorithm drove the multi-objective optimization.

BENEFITS – The final design resulted in the best possible combination between the two opposing objectives.  and decreased the force acting on the crush cans behind the bumper​ by ~6.25% while reducing the bumper’s mass by ~8.25%. A multi-objective optimization and design environment is crucial in obtaining these results and they would not be possible using a manual design process. In addition, automating the design evaluation process using modeFRONTIER saves the designer’s time and allows them to concentrate on new safety concepts.