正多边形基多胞薄壁管的吸能特性

多胞薄壁结构具有轻量化、高比吸能的特点，在汽车、轮船、航空航天等领域得到了广泛的应用。已有研究表明结构的耐撞性与结构的拓扑方式及胞元数量密切相关。为了研究结构形状和拓扑优化对其吸能效果的影响，基于正多边形结构，通过内嵌多边形和外接圆管的方式设计了两类新型多胞薄壁结构，并对这两类多胞薄壁结构进行准静态和落锤冲击实验，利用高速相机记录结构的变形模式，并定量分析了结构的吸能特性。实验结果表明:除正三角形二级内嵌四边形所得结构在准静态加载实验后期出现了局部失稳现象外，其余结构在准静态和落锤冲击实验过程中均保持垂直受压，结构变形模式与吸能效果较好。通过比较两类结构的实验结果得出:不论是在准静态加载还是在落锤冲击的情况下，内嵌多边形结构的各项吸能指标都明显优于外接圆管的结构；同等质量的情况下，内嵌四边形结构的吸能效果明显优于内嵌三角形的结构。

Energy absorption capacity of regular polygon-based multi-cell tubes

With the characteristics of light weight and high specific energy absorption, multi-cell thin-wall structures have been widely used in automobile, ship, aerospace and other fields. Previous studies have shown that the crashworthiness of a structure is closely related to its topology and cell number. In order to study the influence of the structural shape and topology optimization on energy absorption, based on regular polygon structures, two kinds of new multi-cell thin-wall structures were designed by embedding polygons in the basic structures given and circumscribing circular tubes to them, respectively. Meanwhile, quasi-static compression and drop-hammer impact tests were carried out on the two kinds of multi-cell thin-wall structures. The deformation modes of the structures were captured by high-speed cameras, and their energy absorption characteristics were studied quantitatively. The experimental results show that local instability occurred in the structures obtained by second-order embedding quadrangles into the basic regular triangle tubes in the later stage of the quasi-static loading test; the other structures were compressed vertically in the quasi-static compression and drop hammer impact tests, and their corresponding deformation modes and energy absorption capacities were excellent. By comparing the experimental results of two kinds of structures, following conclusions are drawn: the energy absorption of the polygon-embedded structures is obviously higher than that of the structures by externally circumscribing a circular tube under quasi-static loading and drop hammer impact tests; the energy absorption performance of the quadrangle-embedded structure is obviously better than that of the triangle-embedded structure with the same mass.