内聚力单元在Voronoi元胞的晶间断裂模拟中的应用  

The Application of Cohesive Elements in Numerical Simulations of the Intergranular Fracture in Voronoi Cellular Models

作　　者：张帆[1] 赵建平[1] 

机构地区：[1]南京工业大学机械与动力工程学院,南京211816

出　　处：《组合机床与自动化加工技术》2013年第11期26-29,34,共5页Modular Machine Tool & Automatic Manufacturing Technique

基　　金："十二五"国家科技支撑计划项目(2011BAK06B03和2012BAK13B03)

摘　　要：应用二维Voronoi算法进行晶粒的几何建模,采用粘聚力模型模拟晶界的分离现象。以多晶铝为研究对象,研究了无缺陷条件下,施加单向拉伸载荷时,晶界的损伤和失效,以及整个模型的应力分布,并与有缺陷、单向拉伸时,晶界的损伤、应力的分布进行了对比研究,发现在单向拉伸加载的情况下,垂直于拉伸方向,最靠近加载边界的一条晶界带上出现了连续的失效单元,形成晶间断裂"裂纹"。模拟结果表明,随着单向拉伸载荷的增大,多晶铝晶界的损伤会加剧;晶界带上缺陷的数量与分布影响了整个模型的应力分布,因此不同内聚力单元的应力值随着载荷的增加呈现出不同的变化规律。The 2D Voronoi algorithms were used for geometric modeling of crystalline grains. A cohe- sive interface model was used to simulate the process of grain-boundary separation. Polycrystalline alumi- num was chosen as the research object. Under the condition of no defects while the uniaxial stretching load was applied, damage and failure of the grain boundaries as well as the stress distribution of the whole model were investigated. Based on this, a comparative study on grain-boundary damage and stress distribution was carried out in the case of defective while uniaxially stretched. It has been found that in the case of uniaxial stretch continuous failure elements appeared on the grain boundary perpendicular to the stretching direction, closest to the loading surface. This led to the formation of the so-called interg- ranular fracture ＇ crack＇ The simulation results showed that as the uniaxial tensile load increased the damage to the grain boundaries of polycrystalline aluminum would exacerbate, and due to the effect of quantity and distribution of the defects in grain boundaries on stress distribution of the entire model differ- ent cohesive elements showed a different variation in stress value with the increase of the load.

关 键 词：多晶铝 晶间断裂 晶界损伤 

分 类 号：TH122[机械工程—机械设计及理论] TG111.91[金属学及工艺—物理冶金]