Secondary void interactions under shear in thin porous sheets

A compressive stress state decreases the mechanism of void growth in metals. However, in reality, void sheets are evidenced on the fracture surface of metallic shear-compression specimens. The prevailing stress state in the gauge is in contrast to the features observed on the fracture surface. This work examines the mechanical fields in the surroundings of a void under shear as a realization of the mechanical behavior of a ligament between coalescing voids. It is shown that the presence of secondary voids in the surroundings of one primary void reduces the average triaxiality in the cell and homogenizes its distribution; thus, it can be surmised to be mechanically favored. This paper examines this point from a micromechanical perspective utilizing the periodic unit cell method with a single void in its center as a reference case to be compared with other configurations of voids distributed in the cell. It is hypothesized that nucleated voids grow and promote nucleation and growth of voids around them - a mechanism to describe void sheet formation as a positive feedback loop process. The effect of extra secondary voids on the mechanical fields is examined and correlated to their size and location with respect to the existing primary void.

Automated summary

This paper examines the mechanical fields in the surroundings of a void under shear as a realization of the mechanical behavior of a ligament between coalescing voids. The presence of secondary voids is shown to reduce the average triaxiality in the cell and homogenize its distribution, indicating a mechanical advantage. The effect of extra secondary voids on the mechanical fields is examined and correlated to their size and location with respect to the existing primary void.