中文摘要：

成形极限曲线（FLD）是表示板料成形性能的重要指标。由于板料各向异性的存在，导致了使用1条FLD来表示板料整个面内的成形极限存在很大误差。通过试验分析了板料面内的各向异性对板料应力和应变成形极限曲线的影响，研究了利用三维空间的成形极限曲面代替二维坐标下的FLD来表示材料整个面内的成形极限的方法，经过分析认为板料成形极限面可以为板料成形有限元仿真提供更准确的成形极限判据。

英文摘要：

Forming limit diagram （FLD） and forming limit stress diagram （FLSD） are widely used as a valuable tool for analyzing sheet metal forming. However the normal FLD or FLSD assumes that the forming limit is isotropic on the plane of the sheet. In order to more accurately capture the physics of the material behavior, the issue of forming limit anisotropy must also be addressed. The influence of the anisotropy on the plane of the sheet to the FLD and FLSD is studied by the experiment. The forming limit surface in sheet metal forming can give a more accuracy criterion for the failure of sheet metal in FEM simulation.