梯度厚度多胞管的轴向冲击性能分析和优化设计

Axial Crushing Performance Analysis and Optimal Design of Square Multi-cell Columns with Graded Thickness

在截面上引入梯度壁厚设计是一种很有前景的提高薄壁结构吸能效率和耐撞性能的方法。研究双面梯度厚度方形多胞管在轴向加载过程中的变形模式和能量吸收问题。基于简化的超折叠单元理论分析了通过引入梯度厚度提高吸能效率的可行性,确定了一种多胞管截面材料分布方式,并进行了数值仿真分析。仿真结果表明:在横截面引入梯度厚度使多胞管能量吸收效率(比吸能)最大增加了25%,明显改善了多胞管的载荷稳定性,且在提升比吸能的同时几乎不增加初始峰值力。此外,采用径向基神经网络法求解梯度厚度方形多胞管截面的结构优化问题,优化后管件的比吸能比均匀厚度多胞管增加了35%,验证了在翼板交汇区域增加材料的确可以有效提高多胞管的能量吸能效率。

Employing graded thickness in cross-section is an effective method to improve the energy absorption performance and crashworthiness of thin-walled tubes.This paper put emphasis on the collapse pattern and energy dissipation of square multi-cell structures with double-surfaced gradient thickness during axial loading.A sectional material distribution mode of multi-cell tube,expected to increase energy absorption efficiency by introducing a gradient thickness,was firstly determined based on the simplified super folding element theory.Numerical analyses were then carried out to investigate the effects of graded thickness on mechanical responses.The simulation results show that significant improvements in specific energy absorption(up to 25%)and load stability of multi-cell tube are obtained without the increase of the initial peak force by the employment of graded thickness.Finally,the structural optimization of the cross-section of a graded-thickness multi-cell tube with 4×4 cells is solved by RBF neural network.The optimized structure further increases the energy absorption efficiency(approximately 35%),which validates that adding material in the intersection area of the flanges can effectively improve the energy absorption efficiency of a square multi-cell tube.