晶体塑性有限元分析开孔对多晶板材力学性能的影响

Effect of hole opening on mechanical properties of polycrystalline plate based on crystal plastic finite element

基于ABAQUS子程序VUMAT二次开发平台,将位错和孪晶的演化过程引入晶体塑性有限元方法(crystal plastic finite element method,CPFEM)中,实现了多晶塑性材料力学行为的有限元模拟,并通过试验和模拟结果的对比,验证了所提出方法和二次开发程序的有效性.应用含孪晶效应的晶体塑性有限元方法模拟分析了孔洞对于板材开孔问题的影响,结果表明:(1)当孔径小于板宽一半时,强度损失采用线性近似估算值是偏于安全的,而超过板宽一半时,不宜采用线性估算值;(2)当孔距较小时,孔径排布方式对开孔板材的韧性以及极限承载力有重要影响,排布方式可分弱影响区、强影响区和过渡区3种模式.对于承受单向拉伸荷载的板材,开孔时应选择沿轴线排布的方式.

Based on the secondary development platform of ABAQUS subroutine VUMAT,the dislocation evolution and twinning mechanism have been incorporated into the crystal plastic finite element method(CPFEM),which is used to investigate the mechanical behavior of polycrystalline plastic materials.The validity of the secondary development program is verified by comparing the experimental and simulation results.The CPFEM with its twinning effect simulates and analyzes the effect of holes on the mechanical properties of the plate.Furthermore,linear approximation can be used safely when the aperture is less than half of the plate width;however,it is not suitable for larger apertures.When the spacing between two hole openings is small,their positional arrangement has a significant impact on the toughness and ultimate stress of the plate;this impact can be divided into three modes:weak influence zone,strong influence zone,and transition zone.For the plate with double holes subjected to a tensile load,an arrangement along the axis is the most optimum.