Study on Crashworthiness of Hybrid Gradient Negative Poisson's Ratio Structure Under Multi-conditions

In order to meet the requirements of actual vehicles collision and improve the crashworthiness of vehicle energy absorbing components, this paper proposed a hybrid gradient negative Poisson's ratio structure based on the bionic principle, and established a finite element model. At the same time, the test sample was made for axial compression test to verify the accuracy of the finite element model. Using LS-DYNA, the mixed gradient structures with nine different arrangement modes were simulated under different impact angles and impact speeds. The comparison results of comprehensive crashworthiness indexes show that the optimal arrangement mode under multiple working conditions is the combination of transverse negative gradient and longitudinal positive gradient. Compared with the uniform gradient structure, its comprehensive energy absorption is increased by 19.2%, energy absorption stability is improved by 30.6%, and the improvement is obvious. Through the comparative analysis of the deformation modes of hybrid gradient structures with different arrangement modes, it finds that a single transverse gradient can improve the energy absorption stability of the structure, while a single longitudinal gradient can improve the comprehensive energy absorption performance of the structure. Because of the reasonable material distribution, the optimal hybrid gradient structure takes into account the comprehensive energy absorption and energy absorption stability and explains the reason of the excellent comprehensive performance of the optimal arrangement from the internal mechanism, which is conducive to the engineering of the mixed gradient negative Poisson's ratio structure. © 2022, Editorial Department, Journal of South China University of Technology. All right reserved.