Theoretical Research on the Initiation and Propagation of Brittle Crack with Special Reference to SOD Tests

Abstract

In the theory of the brittle crack propagation, the dynamical effects are added to the Griffith's energy condition. At room temperature, the plastic work done occuring in “shear lip” zone, was also considered besides the “surface work” proposed by Orowan. The conditions of the initiation of crack were obtained considering both the energy and : the yield stress. The mechanism of initiation in the SOD tests, Esso Brittle Temperature, and the temperature depending critical stress were obtained theoretically.