Extension of Crack Energy Density Concept to Arbitrary Direction and Energy Release Rate to Non-self-similar Crack Growth

Abstract

Crack energy density is a parameter which was proposed as one of the most important fracture parameters by one of the authors and enables us to make a unified smooth description of fracture mechanics from linear to non-linear problems. In this paper, the crack energy density concept is extended to an arbitrary direction except self-similar direction, the relations between the newly defined parameter ε_φ and well-known fracture parameters ( J_φ -integral, stress intensity factor) are obtained, and the availability of ε_φ as fracture criterion to mixed mode crack problems is demonstrated. It is also shown that crack energy density becomes equal to energy release rate in case of elastic problems, therefore, it can be said that the energy release rate to non-self-similar crack growth which has not been solved yet is given by the expression of ε_φ in terms of stress intensity factors obtained.