NUMERICAL ANALYSIS OF INTERGRANULAR DAMAGE AND FRACTURE BEHAVIOR OF BRITTLE CONTINUA WITH STOCHASTIC GRAIN BOUNDARIES

摘要

Intergranular fracture is a common failure mode in continua. Weak interfaces or grain boundaries are easily damaged and cracked under loading. Thereby, the fraction and distribution of the weak interfaces plays an important role in the intergranular fracture of brittle solids. In this paper, we study the influence of weak interface fraction and connectivity on the intergranular failure of brittle solids. A two-dimensional stochastic finite element method (SFEM) is used to investigate the stochastic intergranular damage and failure. The grain interface is treated as a cohesive zone. The strength and toughness of the isolated interface is random. First, the strength distribution of the interfaces is treated to follow a normal distribution. The failure process and the fracture performance of the solids are investigated. Then, the interfaces are divided into two groups: one is weak interface and the other is strong interface with specific interface properties, respectively. The influence of the weak interface fraction and connectivity on the fracture behaviors is analyzed and discussed. It is found that the fracture energy do not decrease monotonously with the increase in the weak interface fraction. In a certain stage some toughening effect with increasing weak interfaces exists. On the other hand, weak interface connectivity statistically has a little influence on the intergranular failure of brittle solids.