大幅面板材渐进折弯成形的本构建模及模拟

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

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.

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 semiel- lipse-shaped （FEM） are workpiece with super length and large opening of sheet metal,3D ABAQUS finite-element models establish, and the multiple-step incremental air-bending forming and springback processes are sim- ulated. 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 con- stitutive model under the plane stress condition.