Creep analysis of surface-cracked plates by a creep line-spring method

The creep line-spring method proposed in this paper is based on the solutions for the following two problems: a creep crack under non-steady creep condition; an elastic-plastic surface-cracked plate. For the problem of a non-steady creep crack, an engineering approach for estimating the load-line displacement, crack-tip J and C integrals is presented by extending the engineering approach for elastic-plastic fracture analysis to creep analysis. For solving the elastic-plastic surface crack, a simplified elastic-plastic line-spring method is applied. These two approximate solutions are checked by the finite element method. On the basis of the above two approximate methods, a creep line-spring method is proposed and the corresponding fundamental equations are established. The creep line-spring method is used to estimate creep fracture parameters for three-dimensional cracks. In order to check its accuracy, several surface-cracked plates under uniform tension are analyzed by the creep line-spring method and by the three-dimensional finite-element method. The numerical results show that the creep line-spring method is in good agreement with the finite-element method and has the same accuracy as the common elastic-plastic line-spring method.