Local and non-local approaches to creep crack initiation and propagation

Abstract

A functional form of local brittle strength conditions for a time- or history-dependent materials is presented. The particular strength condition associated with the Robinson linear damage accumulation rule and the power-type durability diagram is employed to formulation and analysis of creep crack initiation and propagation problem. The problem is reduced to a non-linear integral Volterra equation, which can be transformed to a linear one for the case of a single crack. Analytical solutions of some simple problems for linear viscoelastic materials are presented for that case and shortcomings of the local approach are pointed out. A non-local approach free from the shortcomings is presented along with an example of its implementation