中文摘要：

根据单位体积塑性功相等原理，基于Druker公设以及等向强化模型，利用比例加载的特点，推导出板料在无卸载比例加载路径下的双向拉伸本构模型，并给出几种不同屈服准则下的本构模型。采用两种薄钢板BH220、SPEN进行了十字形双向拉伸实验研究，给出了这两种薄钢板在加载比例1：1和2：1情况下应力应变关系的理论曲线和实验曲线对比分析结果。结果表明，在小变形范围内，采用Hosford、Barlat89、Mises屈服准则得到的双向拉伸应力应变曲线与实验结果符合得较好。结合已有文献的研究结果说明：在小变形范围内以及无卸载比例加载路径下双向拉伸本构模型是正确性的；在小变形比例加载情况下，各向异性板料的强化规律为等向强化。

英文摘要：

Based on the principle of plastic work equivalent per unit volume, Drucker flow rule and isotropic hardening model, a new expression of stress-strain relationship of biaxial tension for different loading paths, which used firsthand uniaxile tension test data, were derived from existing yield criteria such as Hi1148, Hi1190, Barlat89, Hosford and Mises yield criteria, The true stress- true strain curves of two kinds of steel sheet,BH220 and SPEN, for loading ratios 1 ： 1 and 2 = 1 were determined from uniaxial tension and formulae obtained above. It is found that for steel sheet the calculated true stress-true strain curves based on the Hosford, Barlat89 and Mises criteria are much better agreement with the experimental data points, whereas Hi1148 overestimates the values, This result is consistent with the result obtained in previous paper, It shows that the constitutive model presented here is useful and the isotropic hardening rule is correct in proportional loading path for sheet with in-plane isotropy.