Creep Fracture Under Remote Shear

Abstract

Under compressive mean stress, creep fracture may occur due to microcrack growth. Cavitation is suppressed by the presence of hydrostatic compression, and voids evolve into sliding microcracks. The microcracks elongate and rotate and cause global softening. Deformation may concentrate in shear bands and fracture may ensue at low overall strains. It is thought that this process can occur in rate dependent materials at high homologous temperatures, and in rate independent plastic solids.

In the present work, softening due to two dimensional sliding microcracks and three dimensional ellipsoidal voids is examined for a material which behaves in a linear viscous manner, and is loaded under remote simple shear. For the case of sliding microcracks, the role of crack growth and internal friction on softening is determined. The concentration of deformation in a shear band is also explored. For the ellipsoidal voids, the effects of a rigid particle inside the void on the growth of the void and on the macroscopic softening are calculated.