FRACTURE INSTABILITY OF NOTCHED CRACKED PLATES CHARACTERIZED BY THE STRAIN-ENERGY DENSITY THEORY

The fracture instability of a mechanical system is analyzed by the strain energy density theory. The local relative minima of the strain energy density function dW/dV referred to local coordinate systems at each point of the body are distinguished from the global minimum of dW/dV, G, which is referred to a fixed global coordinate system. The distance l between L and G along the fracture trajectory is introduced as a length parameter to characterize the fracture instability of the system. Numerical results are obtained and discussed for a cracked plate with two symmetrical notches subjected to a monotonically rising tensile stress perpendicular to the crack axis.