大幅面板材渐进折弯成形的本构建模及模拟

为了提高大幅面板材成形的模拟精度,在板材折弯平面应变假设条件下,推导出基于Hill各向异性屈服准则的弹塑性本构方程.借助ABAQUS有限元软件本构模块用户子程序接口,通过编程将上述推导的应力-应变本构关系显示表达式嵌入ABAQUS分析平台.以超长大开口半椭圆形工件成形为例,建立了大幅面钢板渐进折弯的三维弹塑性有限元模型,并数值模拟了多道次渐进折弯成形及回弹全过程.模拟效果和工程应用结果表明,与传统的基于平面应力假设的本构关系模型相比,采用平面应变假设的本构关系模型的模拟结果更接近实验值.

Constitutive model and numerical simulation for incremental air-bending forming of large area sheet metal

To improve simulation accuracy for air-bending forming of large area sheet metal,under the plane strain condition,the explicit expressions of elastic-plastic constitutive equation related to Hill anisotropic yield criterion are presented and implemented to ABAQUS software as the user subroutines.By forming the semiellipse-shaped workpiece with super length and large opening of sheet metal,3D ABAQUS finite-element models(FEM) are establish,and the multiple-step incremental air-bending forming and springback processes are simulated.The simulation results show that the results predicted with Hill’s yielding criterion under the plane strain condition are in much better agreement with experimental data than those predicted with traditional constitutive model under the plane stress condition.