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基于Voronoi算法对铝合金焊接接头进行细观组织建模,构建三维等轴晶、柱状晶区结合区域的多晶模型。结合接头初始晶粒取向,并将其赋予到多晶模型中。运用晶体塑性理论,编写用户自定义材料子程序,对焊态下及经腐蚀后的接头在拉伸状态下的细观应力分布进行数值模拟研究。结果表明:在拉伸形变的过程中,接头细观最大应力出现在柱状晶区、等轴晶结合区域,并且随着腐蚀的平均深度和表面损伤度增加,蚀坑边缘产生应力突变,其应力峰值变大,容易成为裂纹起裂的源头。
Based on the Voronoi algorithm, the microstructure of the aluminum alloy welded joint was modeled to construct the polycrystalline model of the three-dimensional equiaxed and columnar regions. The initial crystal orientation of the joint is combined and assigned to the polycrystalline model. Using the theory of crystalline plasticity, a user-defined material subroutine was written to study the numerical simulation of the meso-stress distribution in the as-welded and welded joints under tension. The results show that the maximum stress of the mesoscopic joints appears in the columnar zone and the equiaxed zone during the tensile deformation. With the increase of the average depth of corrosion and the increase of the surface damage, the stress on the edge of the pit is abrupt, and the stress Peak becomes larger, easily become the source of crack initiation.