屈服准则对DC05钢板十字拉深变形预测的评价

Assessment of yield criterion for deformation prediction in cross-die deep drawing of DC05 steel sheet

结合国际成形论坛十字拉深实验考题,分别采用Mises、Hill48和Yld2000-2d这3种屈服准则和Hockett-Sherby硬化模型集成的本构模型描述DC05钢板力学行为,并建立三维弹塑性有限元模型,预测十字拉深成形的面内主应变和拉深毛坯外轮廓线。重点关注屈服准则对变形预测精度的敏感性分析,以及DIC测量复杂应变路径下的拉深变形分析。在板材力学行为描述方面,Yld2000-2d能同时兼顾应力和变形各向异性特性,而Hill48只能描述其一。十字拉深成形数值预测与实验测量对比结果表明,材料流动的预测和实验趋势吻合,屈服准则对面内主应变的预测影响非常显著,但是计算和测量结果存在显著偏差;预测结果相对实验测量值均偏低,其中Hill48-R预测面内主应变的能力明显高于其他屈服准则,而Yld2000-2d由于受到应力预测偏差的干扰,反而精度不是很理想;另外,对于复杂外轮廓线预测也存在同样的偏差趋势。

By means of cross-die deep drawing experimental benchmark provided by Forming Technology Forum（FTF2015）,three yield criteria,i. e.,Mises,Hill48 and Yld2000-2 d,integrated with Hockett-Sherby hardening model,were employed to describe the mechanical behavior. And three dimensional elastc-plastic FEM model was established to predict in-plane principal strain and draw-in outline. By using digital image correlation technique,the sensitivity analysis of different yield criteria on the prediction of plastic deformation was assessed as well as its deformation analysis under complex strain path. For the description of mechanical behaviors,Yld2000-2 d could exactly capture both yield stresses and anisotropic characteristics simultaneously,but Hill48 model was able to describe either of them. The comparison of deformation predication of cross-die and experimental result indicates that,even though the simulations of material flow are quite acceptable,significant differences still exist. The anisotropic yield criterion makes a remarkable effect on the in-plane principal strain prediction,and all the numerical data are lower than the experimental one. Hill48-R anisotropic yield criterion predicts better strain distribution than the others,while Yld2000-2 d has a poor prediction due to its compromise of stress prediction. Additionally,discrepancies of them are also observed in draw-in outline.