TWO-PARAMETER CRACK GROWTH CRITERION IN DYNAMIC FRACTURE MECHANICS

摘要

We propose a model and a two-parameter criterion of the dynamic fracture of a solid body at the moment the crack transitions from stable to unstable growth. We formulate on the basis of the energy balance for the two-dimensional Griffith problem a two-parameter criterion of the failure of a body with unstable crack propagation. In the model we consider the difference between the specific energy of the surface stresses and the specific surface energy of the solid body. The criterial characteristic of unstable growth of the crack at the moment of the initiation of its dynamic propagation depends both on the constants of the solid body and on the crack dimensions. We substantiate theoretically the connection of the dynamic fracture toughness with the static toughness and the velocity of the unstable crack.