Crashworthiness topology optimisation of a crash box to improve passive safety during a frontal impact

Abstract This paper focuses on the application of topology optimisation algorithms to improve the crashworthiness of heavy passenger vehicles, in frontal impact conditions. The objective is to find the optimal arrangement of material to minimise compliance, satisfying a volume constraint. Ultimately, it is intended to analyse the influence of this component in the energy absorption capability of the vehicle structure during a crash. Crashworthiness design plays a crucial role in the automotive industry, particularly in enhancing passenger safety. It aims to develop structures that can absorb more energy while minimising intrusion, to maintain the driver’s survival space. If so, crashworthiness design deals with conflicting objectives, and optimisation methods can be used to find a compromise between these parameters. The application of topological optimisation in the context of vehicle structure crashworthiness is still limited, mainly due to the high computational costs associated with crash simulations that deem these approaches impractical. To tackle this difficulty, this study performed the optimisation process on a single component, a crash box, employing optimisation algorithms built within a Matlab code, that iteratively interfaces with Abaqus® where the non-linear crash simulation is performed. Afterwards, the optimised component was incorporated into the coach chassis baseline and tested using an already established finite element model on VPS/PamCrash®, simulating a frontal impact, according to the ECE R29 regulation. The application of this methodology demonstrated that evolutionary algorithms can effectively be applied for topology optimisation under crashworthiness conditions, generating an optimised crash box that improves the crashworthiness metrics of the coach baseline structure.