Crash Analysis and Size Optimization of a Vehicle’s Front Bumper System

Abstract

Bumper beams and crash boxes are structural vehicle elements that have very critical functions during frontal collisions. This study examined the energy ab-sorbed by the front bumper system and the reaction forces to the cage structure representing the vehicle cabin frame during a full frontal crash against a rigid wall. For this purpose, 25 different crash analyses were conducted using the ANSYS software by changing the sheet thickness values of the bumper beam (t1) and crash boxes-frontal crash rails (t2) that make up the front bumper system. The internal energy (absorbed energy) of the front bumper elements from the analysis results and the reaction forces acting on the representative cage struc-ture in the opposite direction to the movement were examined. When the ob-tained data were interpreted according to variable thickness, it was observed that the variable t2 significantly affected both the absorbed energy and reaction force results, while the variable t1 did not have a significant effect on the results. Based on this, the thickness value t2 was determined as the design variable of the size optimization problem. When the optimization problem established with the reac-tion force and absorbed energy constraint functions was solved, the optimal t2 thickness value with the highest absorbed energy / peak reaction force ratio was found.