Modelling of Creep Crack Growth
Models for describing creep crack growth in terms of linear and non-linear fracture mechanics concepts are presented. When an elastic stress field is preserved at a crack tip it is shown that crack growth rate can be correlated by the stress intensity factor K and when a creep stress distribution is attained by the creep fracture parameter C*. However since creep strains of about the elastic strains only are required for stress redistribution, it is demonstrated that C* is likely to characterize crack growth in brittle as well as ductile materials unless creep ductilities as small as the elastic strains are measured. A procedure for including ligament damage is included for making residual life estimates.
KeywordsStress Intensity Factor Crack Growth Rate Creep Strain Failure Strain Crack Propagation Rate
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