A progressive damage growth model for failure of rocks under compression has been developed. This model considers incremental growth and eventual instability of a shear fault nucleus, which in turn, is considered as an elliptical inhomogeneity composed locally of a cluster of grain boundary cracks, using the concept of stress enhancement factors. Model predictions with consideration of statistical grain boundary strength distribution for each rock-type, correlated dramatically with the widely available failure data on different rocks. The model is presented in a comprehensive well-regarded paper in the J. Geophysical Research-Solid Earth 103, B10 91998), 23,875-23,895.

Energy criterion for crack deflection at an interface between two anisotropic solids for a normally impinging crack was derived using the method of singular integral equations. This work extended the highly regarded work of Prof. John Hutchinson for isotropic media. Because of the use of anisotropic fibers, results of our analyses have been used by researchers motivated by micromechanical design and manufacturing of composite materials. This work is presented in J. Mechanics and Physics of Solids, 42,8 (1994), 1247-1271.

Motivated by the need to understand the phenomenon of crack nucleation in brittle solids (particularly ice) due to elastic grain anisotropy, two and three-dimensional stress singularities for arbitrary grain junction and triple point geometries were determined in brittle polycrystals, and related to the energetics of the crack nucleation process (J. Mechanics and Physics of Solids, 45 ,9 (1997) 1495-1520). By combining these calculations with local observations of grain boundary sliding events in ice polycrystals (Acta Metallurgica et Materialia 43, 10 (1995) 3791-3797), the issue of crack nucleation in ice was addressed correctly for the first time.