Topological optimization of the roof structure of a passenger car in order to increase energy intensity in a side impact

Abstract

This article considered the main issues of finding options for strengthening the roofing of the vehicle body based on topological optimization in order to meet the requirements of passive safety with a minimum mass. The method for achieving this goal was mathematical modeling using the Topology Optimization modules of the ANSYS software package and the explicit dynamics of LS-Dyna. In order to test the effectiveness of the reinforcements, the pillar side impact according to UNECE 135 “Uniform provisions concerning the approval of vehicles with regard to their performance in side impact on a pillar” was selected as the loading mode. The efficiency criterion was the energy intensity of the body, defined as the ratio of the energy of the system to the residual (plastic) deformation at the level of the center of the door. Based on the topological optimization, two variants of the arrangement of the reinforcing elements, practically equivalent in efficiency, were obtained. For the most complete assessment of the influence of the parameters, several options for strengthening the roofing were considered: placement of steel reinforcing elements; placement of foam aluminum under the roof; combination of steel elements with filling their cavities with foam aluminum. Based on the simulation results, a comparative assessment of the effectiveness of the considered amplification options was carried out. The most effective were the options for reinforcing the roofing with channel-shaped beams and filling them with foam and the option for reinforcing the roofing with channel-shaped beams and diagonal bridges in them, causing it to increase compared to the original structure by 20.88 and 19.94%, respectively, but at the same time the mass of the first option is 42 kg less than the mass of the second.