Thermal activation of rupture and slow crack growth in a model of homogenous brittle materials

摘要

Slow crack growth in a model of homogenous brittle elastic material isdescribed as a thermal activation process where stress fluctuations allow toovercome a breaking threshold through a series of irreversible steps. We studythe case of a single crack in a flat sheet for which analytical predictions canbe made, and compare them with results from the equivalent problem of a 2Dspring network. Good statistical agreement is obtained for the crack growthprofile and final rupture time. The specific scaling of the energy barrier withstress intensity factor appears as a consequence of irreversibility. Inaddition, the model brings out a characteristic growth length whose physicalmeaning could be tested experimentally.