SUPERSONIC CRACK PROPAGATION IN BRITTLE FRACTURE FAULT ZONE: CAN EXPLAIN KERMAN AND KERMANSHAH FAULTS?

In a recent article in Nature, a team of scientists from Max Planck Institute for Metals Research in Stuttgart and IBM Almaden Research Center in San Jose, California study the dynamics of brittle crack propagation with large-scale atomic simulations. In this article the scientists report the discovery of an important missing feature in the existing theories of dynamic fracture: The elasticity of solids depend on their state of deformation. Metals will weaken, or soften, and polymers may stiffen as the strain approaches the state of materials failure. "It is only for infinitesimal deformation that the elastic moduli can be considered constant and the elasticity of the solid linear," says Prof. Dr. Huajian Gao, Director at the Max Planck Institute for Metals Research in Stuttgart, Germany. "However, many existing theories model fracture using linear elasticity, and neglect the considerable difference in material behavior at small and large strains. Certainly, this can be considered questionable since materials fail at the tip of a dynamic crack because of the extreme deformation." The scientists hence postulated that hyperelasticity, the elasticity at large strains, can play a governing role in dynamic fracture. In their studies, the scientists show that hyperelasticity, the elasticity at large strains, can dominate the dynamics of fracture. Cracks moving in solids absorb and dissipate energy from the surrounding material.

کلیدواژه ها:

Simulation model ، Crack propagating ، Rayleigh and shear wave speeds ، Speed of sound solid surface