Effect of Two-Scale Void Interaction on Crack Path Behaviour Under Mixed-Mode Loading

The void interaction mechanism in front of the crack tip has been studied thoroughly. Various numerical analyses have been conducted to account for the distribution of primary voids, the initial shape of primary voids, and mix-mode loading on crack extension. In most of the work, only primary voids modeled in initial crack plane. A few studies also consider the secondary voids as being homogeneously distributed throughout the matrix. The interaction between the two distinct scales of voids has not been analyzed yet. In this work, the interaction effect of primary and secondary voids on the ductile crack propagation is analyzed. A plane strain, semi-infinite cracked small scale yielding boundary layer model is considered and the mix mode I and mode II of K-field.loading is applied. “β” defines the ratio of mode II and mode I loading. Both larger and smaller voids are modeled explicitly in the process zone. Initially, only the primary voids configuration analyzed for the different loading scenario. Then, secondary voids are introduced in the intervoid ligament of primary voids to account for their effect on the material’s toughness. For certain configurations and initial shapes of the secondary voids, the material resistance curve is plotted and compared with the case that consists only of primary voids. The present study reveals that the initial shape and distribution of secondary voids as well as the different value of “β” may alter the voids interaction mechanism and the crack may differ the path which affects the toughness of the material.