【摘要】 针对多晶金属材料微观结构的多样性和破坏过程的复杂性，在基于Voronoi图构建多晶体微观结构图的基础上，结合近场动力学方法，将多晶体离散为一系列物质点，通过积分求解近场域内各物质点的相互作用力，建立了外界载荷作用下多晶材料内部裂纹扩展及结构破坏的损伤演化模型，对多晶材料取不同晶界强度系数和晶粒大小时的断裂性能进行研究。研究结果表明，当晶界强度系数β≥1时多晶材料通常发生穿晶破坏，β<1时材料则容易发生晶间破坏；在材料表现为穿晶破坏模式下，随着晶粒尺寸的减小，材料的抗断裂性能得到提升。更多还原

【Abstract】 In view of the diversity of the microstructure and the complexity of the failure process of polycrystalline metal materials, the failure of polycrystalline metal materials was numerically simulated and analyzed based on the Voronoi diagram and the Peridynamic theory. In the process of analysis, the polycrystal was divided into a series of material points, the interaction force of each material point in the “horizon” were solved by integral, and the damage evolution model of internal crack propagation and structural impairment of polycrystalline materials under external loads was established. The results show that when the grain boundary strength coefficient is greater β≥1, the polycrystalline material usually undergoes transgranular failure, and when β< 1, the material is prone to intergranular failure. In the transgranular failure mode, the fracture resistance of the material is improved with the decrease of grain size.更多还原