基于动静联合算法和混合非线性随动强化模型的薄板U形冲压回弹分析

Springback analysis of U-shape bending parts based on dynamic-static combined algorithm and mixed nonlinear kinematic hardening model

利用非线性随动强化及其混合强化模型能够较准确地描述材料在循环载荷下的力学行为,从而较好的反映材料在反向加载时的应力应变关系。本文讨论了非线性随动强化模型背应力的特点及其混合叠加方法,同时基于Mises屈服准则分别采用单个非线性随动强化模型、双非线性随动强化叠加模型、三非线性随动强化叠加模型,针对Numisheet2011给出的薄板U形冲压标准考题进行了有限元模拟验证和研究。结果表明:在回弹预测问题上,由于多个非线性随动强化材料模型的叠加有助于更好的描述反向加载过程中材料的非线性行为,使其能够更准确的预测回弹。在板料成型的应力分布预测方面,三种材料模型给出的结论差别不大,单个非线性随动强化材料模型对应计算结果能够满足应力分布预测的精度要求。

The back force characteristics and mixing superposition method of the nonlinear kinematic hardening model were discussed based on Mises yield criterion, and the U-shaped stamping standard question given by Numisheet 201 lwas studied by means of FEM simulation and verification using the single nonlinear kinematic hardening model, double nonlinear with kinematic hardening model and three nonlinear kinematic hardening model. Results show that the multiple nonlinear kinematic hardening material model can better de- scribe the reverse loading process in material nonlinear behavior to overcome the changes in the plastic modulus, which can predict the spring back more accurately. In the prediction of the stress distribution of sheet metal forming, the conclusions of the three models are not very different, and the corresponding calculation results can meet the accuracy requirements for the prediction of the stress distribu- tion.