Evaluation of the Effects of the Forming Process on the Simulation of a Crash Test of an Automotive Bumper 2020-36-0147

Crash-Test is a vehicle impact test that aims to analyze and evaluate a vehicle’s capacity to withstand different types of collisions. During the shock, most of the impact energy is absorbed by the structural elements of the vehicle in order to greatest protection possible to the passengers. In addition to the test with the impact of the actual vehicle, simulation analysis using the Finite Element Method (FEM) is used. The crash test is extremely expensive and, therefore, unfeasible to be performed repeatedly. In this way, the FEM plays an important role in the analysis of the vehicle's impact resistance, reducing development time and project costs. However, many factors that affect the accuracy of the simulation are not adequately taken into account. Most of the structural components of the vehicle body are manufactured by the stamping process. This manufacturing process imposes a plastic deformation on the parts along with a distribution of non-uniform thickness, residual stresses, and strain hardening of the grains, especially in high strength and high ductility steels. In this paper, the effects of the manufacturing process (thickness variation, plastic strain, hardening and residual stresses) were investigated, acting separately and also simultaneously, in an impact simulation of an automotive bumper. First, the impact simulation was performed, disregarding the influence of the manufacturing process. Then, the simulation of the forming of the structural components and the mapping of the effects. The mappings had a significant influence on the analyzed results, both in the maximum displacement, as in the deformation modes and energy absorption.