Creep rupture in a bundle of slowly relaxing fibres

Abstract

In this study, creep rupture in a bundle of slowly relaxing fibres was investigated. The intact fibre was assumed to exhibit linear elastic behaviour; however, its load did not drop to zero instantaneously after breaking but underwent a slow relaxation process, and thus, it introduced a time-dependent behaviour in the system, which was modelled by a Kelvin–Voigt element. Under the assumption of global load sharing for the redistribution of load, the analytical and simulated results showed the formation of two distinct regimes of the creep process depending on the value of the external load. For external loads greater than the critical load, the system suffered a macroscopic rupture in a finite time. However, for external loads smaller than the critical load, the system was characterized by an infinite lifetime. The critical load depended on the ratio of the elastic modulus between the intact and the failure elements, Eb/ E. It was observed that the time to rupture, tf, had a power-law divergence with an exponent −1/2 when the load approached the critical load from above. Moreover, the acoustic emission response was measured from the rate of breaking of fibres in the simulations.