Crashworthiness analysis and multi‐objective optimization of Al/CFRP hybrid tube with initial damage under transverse impact

Abstract Damage can cause uncontrollable changes during the service of a structure, leading to a reduction in mechanical properties and ultimately to structural failure. This paper presents an experimental and numerical study of the crashworthiness of thin‐walled Al/CFRP hybrid tubes with pre‐existing transverse compression damage under transverse impact loading. Experiments shows that initial damage has a more limited effect on the energy absorption capacity of hybrid tubes under impact loading, but has a greater effect on their deformation pattern and the evolution of damage. After impact, cracks on the surface of the damaged tube propagate into multiple, discontinuous cracks with a total length similar to the length of the tube. Conversely, only short cracks are generated on the intact tube. Subsequent finite element simulations demonstrate the validity and accuracy of a coupled multi‐loads model and explore the effect of different structural parameters (winding angle and number of CFRP layers, and thickness of Al tube) on the crashworthiness of the hybrid tubes. Finally, a multi‐objective snake optimizer algorithm (MOSO) was used to obtain an optimal hybrid tube structure for multiple loading conditions in order to minimize the effect of initial damage on the crashworthiness of the hybrid tube. In comparison to the simulation outcomes for the original structure, the peak crushing force (PCF) decreased by 28.46%, whereas the specific energy absorption (SEA) increased by 44.59%. Highlight The effect of pre‐existing damage on the crashworthiness and deformation pattern of hybrid tube structures is investigated by means of experimental and numerical simulations. A multi‐step finite element model was developed using the restart method to realize the crashworthiness analysis of the hybrid tube under multiple load coupling conditions. The prediction accuracy of four surrogate models for the crashworthiness of hybrid tubes is compared and analyzed. The multi‐objective snake optimizer algorithm (MOSO) is proposed to obtain the optimum hybrid tube structure for multiple loading conditions.