棱边强化薄壁方管静动态轴压理论和仿真研究

Theoretical and Simulation Study on the Static and Dynamic Axial Crushing of Ridgeline Strengthened Thin-walled Square Tubes

本文旨在对棱边强化薄壁方管的静动态轴向压溃进行研究。首先分析了方管静态平均压溃力公式中的能量等效流动应力选取方法及其对理论预测结果的影响,之后结合Cowper-Symonds经验公式,导出了动态平均压溃力公式。同时基于Hypermesh 9.0建立了440A原始和棱边强化薄壁方管静动态轴向压溃有限元模型,仿真再现了塑性变形过程和压溃力波动状况,仿真值与理论值吻合得较好,最大偏差不超过4.0%。最后,制作若干个棱边塑性应变强化的35钢方管,进行压溃试验,验证了静态轴向压溃理论的有效性,理论值与试验值之间偏差仅为7.1%。本研究为棱边强化薄壁部件的强度设计及其在车身结构中的应用提供了参考。

This paper aims to study the static and dynamic axial crushing of ridgeline strengthened thin-walled square tube.Firstly,the choosing method of the energy-equivalent flow stress in the formula of static mean crushing force for ridgeline strengthened square tube and its effects on theoretical prediction results are analyzed.Then the formula for dynamic mean crushing force is derived based on Cowper-Symonds empirical formula.Meanwhile,the finite element models for 440A original and ridgeline strengthened square tubes subjected to static and dynamic axial crushing are built with Hypermesh 9.0,and a simulation is conducted to reconstruct its plastic deformation process with the fluctuation of crushing force,and the results well agree with theoretical values with a maximum deviation less than 4%.Finally,several 35 steel square tubes with plastic strain strengthened ridgelines are fabricated for conducting static crushing test,verifying the validation of the static mean crushing force formula with a 7.1%derivation from the theoretical value.This study provides some references for the strength design of ridgeline strengthened thin-walled square tubes and their application in vehicle body structures.