一种针对颈缩现象的高强钢板材力学行为研究方法

为表征一种双相钢板材的塑性力学行为,对其进行了4种不同应变率下的单向拉伸试验,结果表明颈缩现象存在于各应变率下的试验中. 为解决颈缩现象中三向应力状态给常规公式计算所得强化曲线带来不可靠性的问题,使用了一种试验与仿真相结合的逆向方法. 首先在试验所得曲线的基础上判断颈缩起始点,并根据该点信息使用Ludwik准则对颈缩后曲线进行外插;再将外插曲线应用于仿真,通过仿真与试验结果的对比优化外插曲线. 将该方法应用于所研究的双相钢材料后,获得了能够准确表征单向拉伸过程的材料曲线.

A Hybrid Experimental-Numerical Converse Method for the Necking Behavior Study of High Strength Steel Sheets

To characterize the plastic behavior of a dual phase (DP) steel, tension tests under four different strain rates were conducted. The results show that necking phenomenon exists in all the tests. To solve the unreliability problem of the conventional data processing method brought by the 3D stress state of the necking behavior, a hybrid experimental-numerical converse method was employed. The onset of necking phenomenon was determined firstly according to the test results and the hardening curve was extrapolated from the necking onset following the Ludwik hardening law. Then, the extrapolated curve was optimized to achieve a good agreement between simulation and experimental results. At last, this method was applied to the studied DP steel, and the hardening curves for the characterization of tension tests were obtained.