轴向冲击作用下嵌套式薄壁球壳结构吸能性能研究及优化设计

摘要

针对单个小直径薄壁球壳吸能能力有限的问题,提出了一种嵌套式薄壁球壳结构,并通过有限元软件模拟其在轴向冲击下的动态响应过程,分析了外球壳厚度、内球壳高度和内球壳厚度对结构在轴向冲击下力学性能和变形模式的影响;建立了以比吸能、冲击荷载峰值为吸能性能的评价指标,以外球壳厚度、内球壳高度和内球壳为试验变量的响应表面模型;基于响应表面模型,通过非支配遗传算法(NSGA-Ⅱ)对试验变量进行优化,提出了不同工况下结构几何参数选取方案.结果表明,结构几何参数对其吸能特性影响显著,建立的响应表面模型准确可靠,优化方法得到了有限元模拟验证,有利于工程实际应用.%Considering the limitation in the energy absorption ability of a single small span thin-wall spherical shell,a new nested thin-wall spherical shell structure was designed and its dynamic response under axial impact was simulated by using a finite element software.The effect of the thickness of the outer spherical shell,the height and thickness of the inner spherical shell on mechanical properties and deformation modes under axial impact were analyzed.A response surface model was established based on the evaluation indexes of specific energy absorption (SEA) and peak crush load(PCL),taking the thickness of the outer spherical shell and the height and thickness of the inner spherical shell as test variables.Based on the response surface model,the test variables were optimized with the non-dominated sorting genetic algorithm NSGA-Ⅱ.Under different working conditions,the selection of the geometrical parameters was put forward.The results show that the geometrical parameters are of significant effects on the energy absorption characteristics.The response surface model is accurate and reliable.And the optimization method which has been verified by the finite element simulation is beneficial in engineering applications.