初始扭转缺陷下梯度厚度薄壁方管的变形模式与吸能性能

Deformation Modes and Energy Absorption Performance of Graded Thickness Thin-Walled Square Tubes with Initial Torsional Imperfections

摘要: 为评估梯度厚度方形金属薄壁管在制造偏差条件下的吸能性能，并探索缺陷背景下吸能性能的提升途径，本文基于LS-DYNA建立了轴向压缩有限元模型。系统研究了梯度厚度设计在准静态压缩下的变形机制，以及扭转型初始几何缺陷对吸能特性的影响规律。研究结果表明：相较于均匀厚度管，梯度厚度设计能有效改变屈曲演化规律，并诱导高耗能的外延变形模式；在理想构型下，梯度管的能量吸收性能显著优于均匀管，其初始峰值压溃力最高降低58.4%，压溃力效率最高提升186.6%。引入扭转型初始几何缺陷会抑制外延模式的发展并导致吸能水平普遍衰减，但梯度管在缺陷条件下仍表现出优于均匀管的吸能能力，具有良好的工程鲁棒性。

Abstract: To evaluate the energy absorption performance of graded thickness square metallic thin-walled tubes under manufacturing imperfections and to explore potential approaches for enhancing their crashworthiness in the presence of defects, a finite element model of axial compression was established using LS-DYNA. The deformation mechanisms of graded-thickness design under quasi-static compression, as well as the effects of torsional initial geometric imperfections on energy absorption characteristics, were systematically investigated. The results indicate that, compared with uniform-thickness tubes, the graded-thickness design effectively alters the buckling evolution process and promotes the formation of high energy-absorbing extensional deformation modes. Under ideal configurations, graded-thickness tubes exhibit significantly superior energy absorption performance, with the initial peak crushing force reduced by up to 58.4% and the crushing force efficiency increased by up to 186.6%. The introduction of torsional initial geometric imperfections suppresses the development of the extensional deformation mode and leads to a general degradation in energy absorption capacity. However, graded-thickness tubes still demonstrate better energy absorption capability than uniform-thickness tubes under imperfect conditions, indicating strong structural robustness in engineering applications.