基于J-C模型的Q235钢的失效准则

J-C model based failure criterion and verification of Q235 steel

使用Instron材料试验机、霍普金森拉杆(SHTB)对Q235钢试件进行了不同温度下的准静态和动态拉伸实验,研究了温度、应变率及应力三轴度对Q235钢失效应变的影响,结果表明:Q235钢失效应变随温度的升高而增加,随应变率的增加而减小,随应力三轴度的增加先减小后增加再减小。基于实验结果对Q235钢J-C失效模型中的温度项进行了修正,并结合数值模拟提出了基于J-C失效模型的应力三轴度三分段式失效准则,通过Taylor撞击实验和数值模拟对给出的模型相关参量进行了验证,实验与模拟结果吻合较好。

In this paper,we conducted quasi-static and dynamic tensile tests on Q235 steel at different temperatures using the Instron tensile strength tester and the split Hopkinson bar and studied the effects of temperature,strain rates and stress triaxiality on the steel's failure strains of Q235.The results show that Q235 steel's failure strains increase with a rise in temperature but decrease with a rise the strain rates while,with a rise in the stress triaxiality,they decrease at first but then increase.Based on these results and combining them with numerical simulation,we modified the item of temperature effects and proposed a revised three-section failure criterion of stress triaxiality for J-C failure model,with relevant parameters determined and verified using Taylor impacting experiments and corresponding numerical simulations.The experimental results accord well with those from simulation.