Influence of forming processes on crashworthiness of automotive components

The upcoming regulations in the area of passive safety and the constant effort to reduce the emission of cars are driving car manufacturers to search lighter components with improved crash performance. Consequently, a spreading use of innovative materials for structural components such as advanced high strength steels is to be observed. The production process of the structural components can affect their crashworthiness owing to the introduction of modifications in the material characteristics during the sheet metal forming process. For instance, the deep drawing and the subsequent operations introduce a work hardening, a thickness variation and a geometry variation, which is partially ascribed to the springback. Such modifications are not uniform through the single part and may relevantly affect its local features. The modifications due to the springback are especially relevant for parts made of advanced high strength steel. In order to obtain an accurate prediction of crash behaviour of structural components, especially for the ones made in AHSS, the crash simulation could be carried out considering the material history. In this paper, a car component was in-depth analysed and a simulation of the forming operations and the following springback was carried out. The results were finally imported in a crash simulation. The forming operations were simulated using Autoform code. The mapping of the material characteristics at the end of the production process was imported in the crash simulation that was carried out using LS-DYNA explicit code. The crash simulation was then repeated using the nominal characteristic of the material (without considering the effect of forming processes). The obtained results were compared in order to point out the influence of the manufacturing process on the crash performance of the component.