金字塔型波纹薄壁管抗撞性分析和优化

 为提高薄壁结构吸能元件的抗撞性能，在传统的光滑圆柱壳表面添加金字塔型波纹。基于显式有限元技术, 应用LS-DYNA软件对这种新型的金字塔型波纹薄壁管进行抗撞性分析。采用Fibonacci搜索方法搜索该波纹管的正多边形截面的最佳边数，以波纹的高度和倾角为设计变量，以结构的吸能为优化目标建立优化模型。采用响应面法拟合目标函数，进行优化设计。半径为40mm的波纹管算例的优化结果表明，金字塔型波纹管在截面为正十一边形、波纹高度为80mm、金字塔形波纹的顶点到中心轴的距离为38.92mm时吸能最大，吸能能力比光滑表面的圆截面结构提高31.88%。新提出的波纹结构可用于实际吸能元件的设计,并为进一步研究奠定基础。

Crashworthiness Analysis and Optimization of Thin-walled Tube with Pyramidal Folding Patterns

Thin-walled structures are often used as energy absorbers to dissipate the kinetic energy of impacting in case of accident. In order to improve the crashworthiness of thin-walled structures, the pyramidal folding pattern is added to the smooth surface of traditional cylindrical shell. LS-DYNA is adopted to analyze the new tube's crashworthiness with explicit Finite Element (FE) technique. Fibonacci Search method is used to search the optimal number of sides of polygon of the new model's section. With the height and obliquity of the pattern as optimization variables, the absorbed energy as the optimization objective, the optimization model is built. Response Surface Method is used to obtain an approximation of the implicit quadratic function to make the optimization objective explicit. And then, the optimization problem can be solved. Take 40mm-radius tube with pyramidal folding patterns as an example, the optimization results show that, when the side number of the section polygon is 11, the pattern's height is 80 mm and the distance from pattern peak to axis is 38.92mm, the pyramidal folding pattern tube has the best ability in absorbing energy. Compared with the traditional smooth cylindrical shell, the energy-absorption ability is improved by 31.88%. The new folding pattern structure proposed in this paper can be applied in designing practical energy absorption components. The directions for further study are suggested.