Abstract

Oblique impact loading conditions are unavoidable in practical applications, which strongly influence the performance response of energy-absorbing structures. In this paper, the finite element models of four typical cellular structures (hexagon honeycomb, re-entrant hexagon honeycomb, star-shape honeycomb, double arrow honeycomb) are established and experimentally validated. The dynamic responses of four structures under different impact angles (from 0 to 30°) and impact velocities (from 5 to 50 m/s) are investigated. On this basis, the influences of impact angle and impact velocity on the specific energy absorption (SEA) and peak crushing force (PCF) of four structures are discussed. The results reveal that the negative Poisson’s ratio structure has the advantage of energy absorption under axial impact due to the characteristics of compression and contraction at the low impact velocity. The hexagonal honeycomb structure has great advantages in terms of comprehensive energy absorption capacity and better stability at varying inclination angles. The Non-dominated Sorting Genetic Algorithm (NSGA-II) coupled with the ideal point method (IPM) is utilised to explore the optimal design of hexagon honeycomb structure, which is then verified by a detailed crashworthiness comparison with the original design. The optimal honeycomb structure shows excellent crashworthiness characteristics and demonstrates great potential for applications in impact engineering, especially the oblique impact loading situations.

摘要

斜向冲击载荷条件在实际应用中是不可避免的，这严重影响了吸能结构的性能响应。本文建立了四种典型蜂窝结构（六角蜂窝、内六角蜂窝、星形蜂窝、双箭头蜂窝）的有限元模型并进行了实验验证。研究了四种结构在不同冲击角度（0 到 30°）和冲击速度（5 到 50 m/s）下的动态响应。在此基础上，研究了冲击角度和冲击速度对比能量吸收（SEA）和峰值破碎力（PCF ）的影响。) 的四个结构进行了讨论。结果表明，负泊松比结构由于在低冲击速度下的压缩和收缩特性，具有在轴向冲击下吸收能量的优势。六边形蜂窝结构在综合能量吸收能力和不同倾角稳定性方面具有很大优势。利用非支配排序遗传算法（NSGA-II）结合理想点法（IPM）探索六边形蜂窝结构的优化设计，并通过与原始设计的详细耐撞性比较来验证。优化的蜂窝结构表现出优异的耐撞特性，在冲击工程中具有巨大的应用潜力，