Oblique compression instability prediction and crashworthiness design for hybrid tube

Abstract

CFRP/aluminum hybrid multi-cell tubes have excellent potential as energy absorbing structures for passenger cars due to their excellent energy absorption characteristics and good designability, but the identification of unstable deformation mode is crucial for energy-absorption regulation. The innovation of this paper lies in the proposal of a universal characterization and prediction method for the oblique compression instability of CFRP/Al hybrid tube. First, a high-precision finite element model of CFRP/Al hybrid tube under multi-angle compression conditions is established and verified through experiments. Second, through the induction and summary of the deformation process, the concept of critical instability angle is introduced. Based on this, a universal characterization method for global bending mode is established and verified. Third, a prediction model for the oblique compression deformation mode of hybrid multi-cell tube based on Support Vector Machine is established. Furthermore, a prediction method for the critical instability angle is proposed and verified. Finally, an integrated multi-objective optimization design model for crashworthiness and lightweight considering the critical instability angle is established, and the influence of the critical instability angle on the optimization solution is discussed. The results show that if the critical instability angle is improperly designed, it will lead to a significant reduction in the energy absorption efficiency of the structure or the presence of substantial design redundancy. This research provides methodological guidance for the integrated design of crashworthiness and lightweight of multi-material thin-walled structures facing energy absorption requirements under multiple loading conditions.