BH220钢板屈服轨迹的双向拉伸实验研究

本文针对建立的十字形双向拉伸试验系统 ,利用有限元模拟优化得到的十字形试件 ,采用载荷控制方式对汽车用薄钢板BH2 2 0进行了不同加载路径下的双向拉伸试验 ,得到了不同加载路径下的应力应变关系曲线 ,并根据塑性功相等的原则 ,对BH2 2 0钢板的试验屈服点与现有屈服准则Hill4 8、Barlat lian、Logan hosford的理论轨迹进行了对比 ,结果表明 ,与试验结果相比 ,Hill4 8过高地估计了屈服轨迹 ,Logan hosford准则比Barlat lian准则接近试验结果 ,尤其在垂直于轧制方向与试验结果吻合较好 ,但在靠近轧制方向其理论轨迹偏高。

Biaxial tensile experimental study on the yield loci of steel sheet BH220

On the basis of biaxial tensile experimental system, auto steel sheet BH220 was studied under different loading paths using optimized cruciform specimens.According to the curves of the true stress-logarithmic strain, the exponent of work hardening become larger when the load ratio is near to 1∶1. Also, the geometry of experimental yield loci were determined based on the equivalent plastic work.The comparison between the experimental data points and the yield loci calculated from several anisotropic yield criteria such as Hill48, Logan-hosford and Barlat-lian shows that Hill48 overestimated the yield stress in all the contours. Among these three yield criteria Logan-hosford gave the best fitness to the experimental data points, especially along the transverse direction.