高分子材料平面应变拉伸变形局部化

将基于应变软化玻璃状高分子材料微观特征建立的ＢＰＡ８－链分子网络模型引入ＵｐｄａｔｉｎｇＬａｇｒａｎｇｅ有限元方法，建立了适于变形局部化分析的大变形弹塑性有限元驱动应力法．在此基础上，数值模拟了初始各向同性高分子材料平面应变拉伸变形局部化的传播过程．探讨了ＢＰＡ模型对具有加工硬化特性的结晶性高分子材料变形分析的适应性；分析了局部化传播过程中颈缩截面的非均匀应力三轴效应；最后，讨论了网格尺寸以及初始几何不均匀性对颈缩扩散以及应力三轴效应的影响

DEFORMATION LOCALIZATION FOR PLANE STRAIN TENSION OF POLYMERS

A kind of BPA eight chain molecular chain network model based on strain softting glassy polymers is introduced into the Updating Lagrange finite element formulation A driving stress finite element method of elastic plastic large deformation suitable for the deformation localization analysis is proposed Using this method, the plastic flow localizing propagation for the plane strain tension of initial isotropic polymers is numerically simulated Adaptation of the BPA model to crystal polymers showing work hardening characters is analyzed; And then, non uniform stress triaxiality effect of necking transverse section during the localized propagation is studied Finally, influences of mesh sizes and initial geometrical imperfection on neck spreading and triaxiality factor are also discussed