A kinetic approach to fracture of solids. II. The time to the fracture of a specimen under constant load in the presence of propagating cracks

Abstract

Abstract The fracture of solids under creep conditions is considered as a process consisting of nucleation due to thermal fluctuations and subsequent coalescence of numerous interacting microcracks. The main crack causing the rupture of the specimen is produced by coalescence of several microcracks and propagates by joining other microcracks which nucleate in its neighbourhood due to local stress concentration. The time to the fracture τ of a homogeneous specimen under constant stress is calculated and is shown to be the sum of the time of generation τ g and the time of propagation τ p of the main crack. τ g is governed by stochastic processes and displays a size effect (dependence on the volume of the specimen), whereas τ p is determined by the stress concentration near the crack during the initial stages of its propagation. Both times are proportional to the time of nucleation τ m of a microcrack.