轨道车辆SUS304不锈钢材料动态力学性能与本构模型修正

DYNAMIC MECHANICAL PROPERTIES AND CONSTITUTIVE MODEL MODIFICATION OF SUS304 STAINLESS STEEL USED IN CARBODIES OF TRAINS

为研究轨道车辆车体常用SUS304不锈钢材料的动态力学性能,进行了0.0002 s^(-1)-500 s^(-1)宽应变率下的动态拉伸试验,得到了不同应变率下的应力应变曲线,结果表明在动态拉伸过程中该材料表现出应变硬化现象,应变率强化效应和一定的热软化效应。为准确描述该材料的动态力学性能,首先建立了该材料在室温下的Johnson-Cook模型。在此基础上,引入绝热温升,建立了塑性应变以及应变率相关的修正Johnson-Cook模型。通过对比,表明修正模型能够较好地描述该材料随应变和应变率增加逐步软化的特性,该修正模型为轨道车辆车体结构耐撞性分析提供了基础依据。

In order to study the dynamic mechanical properties of SUS304 stainless steel commonly used in rail vehicles,tensile tests under wide strain rates of 0.0002 s^(-1)-500 s^(-1) were carried out respectively.The test results show that SUS304 stainless steel exhibits strain hardening during dynamic stretching.As the strain rate increases,the material exhibits a strain rate strengthening effect.At the same time,a certain thermal softening effect is produced.To accurately describe the dynamic mechanical properties of the material,the Johnson-Cook model of the material at room temperature was first established.On this basis,adiabatic temperature rise is introduced,and a modified Johnson-Cook model considering plastic strain and strain rate correlation is established.The modified Johnson-Cook model can better describe the dynamic mechanical characteristics of SUS304 stainless steel,which is the characteristic that the stress gradually weakens with the increase of strain and strain rate.This modified model provides a basic basis for the crashworthiness analysis of the rail vehicle body structure.