一种基于有限元仿真的板料成形极限预测方法

从成形极限图试验中观察得到了板料发生缩颈的2条判断准则：1.板料发生缩颈时凸模与板料接触力出现峰值；2.缩颈区域应变路径向平面应变状态发生突变.在有限元仿真软件中建立成形极限图试验的模型，对不同尺寸的试件进行仿真，根据以上2种准则可以得到在不同应变状态下的缩颈应变成形极限和应力成形极限.在二维坐标系里标出得到的极限点并连成曲线，即为用有限元仿真方法得到的板料应变成形极限图（Forming Limits Diagram,FLD）和应力成形极限图（Forming Limit Stress Diagram,FLSD）.通过与理论计算方法和试验方法得到的结果对比发现用该方法得到的FLD以及FLSD比理论推导出的更接近试验得到的数据

A new method to predict the forming limit of sheet metal based on finite element simulation

A simple method to generate forming limit diagram(FLD) and forming limit stress diagram(FLSD) has been developed. This method is based on the finite element method and uses the peak value of contact force of punch and the change in strain path as two criteria for the necking of the sheet metal. By using a well known dynamic explicit analysis code Pamstamp2G, the process of experimental method to get FLD was simulated. FLD and FLSD obtained in this way were compared with those obtained from the Swift Hill model、NADDRG model and experimental method. Results showed that FLD and FLSD obtained by using this method were more consistent with the experimental results than those obtained by using the theoretical method.