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oai:recercat.cat:2445/188302025-12-04T20:42:51Zcom_2072_1057col_2072_478822col_2072_478917

00925njm 22002777a 4500 dc Kovacs, K. author Nagy, S. author Hidalgo, R. C. author Kun, F. author Herrmann, Hans J. author Pagonabarraga Mora, Ignacio author 2011-07-07T12:53:37Z 2011-07-07T12:53:37Z 2008 We study the damage enhanced creep rupture of disordered materials by means of a fiber bundle model. Broken fibers undergo a slow stress relaxation modeled by a Maxwell element whose stress exponent m can vary in a broad range. Under global load sharing we show that due to the strength disorder of fibers, the lifetime tf of the bundle has sample-to-sample fluctuations characterized by a log-normal distribution independent of the type of disorder. We determine the Monkman-Grant relation of the model and establish a relation between the rupture life tf and the characteristic time tm of the intermediate creep regime of the bundle where the minimum strain rate is reached, making possible reliable estimates of tf from short term measurements. Approaching macroscopic failure, the deformation rate has a finite time power law singularity whose exponent is a decreasing function of m. On the microlevel the distribution of waiting times is found to have a power law behavior with m-dependent exponents different below and above the critical load of the bundle. Approaching the critical load from above, the cutoff value of the distributions has a power law divergence whose exponent coincides with the stress exponent of Maxwell elements. Física de l'estat sòlid Propietats de la matèria Solid state physics Properties of matter Critical ruptures in a bundle of slowly relaxing fibers