Burst avalanches and inter-occurrence times in creep rupture

The statistics of fracture precursors in the creep-damage process are studied on the basis of a proposed dry, non-linear viscoelastic fiber bundle model. This model permits the occurrence of damage avalanches consisting of simultaneous rupture of several fibers. The avalanche size distribution for the global-load sharing rule follows a power law asymptotic behavior analogous to that of static fracture (Kloster M. et al., Phys. Rev. E, 56 (1997) 2615). The statistical behavior of the same distribution, however, for the local-load sharing rule is different from that of the static fracture. Moreover, power law asymptotics apply to times between successive bursts with a universal exponent close to unity - an exponent close to that observed in fracturing processses occuring at vastly different time and space scales.