Pulsed CO₂laser with a self-pumped mirror based on four-wave mixing in the laser active medium

Abstract

We present experiments on the slow growth of a single crack in a fax paper sheet submitted to a constant force F . We find that statistically averaged crack growth curves can be described by only two parameters: the mean rupture time τ and a characteristic growth length ζ. We propose a model based on a thermally activated rupture process that takes into account the microstructure of cellulose fibers. The model is able to reproduce the shape of the growth curve, the dependence of ζ on F as well as the effect of temperature on the rupture time τ . We find that the length scale at which rupture occurs in this model is consistently close to the diameter of cellulose microfibrils.c EDP Sciences Article published by EDP Sciences and available at http://www.edpsciences.org/epl or http://dx.