Fracture Mechanics Characterization of Crack Growth under Creep and Fatigue Conditions

摘要

Concepts to correlate crack growth under high temperature conditions with material parameters of fracture mechanics, e.g., stress intensity factor and line integrals J and C* were investigated. It is shown for different materials that these parameters describe the behavior of cracks independent of geometry and loading conditions within certain limits of validity. The laboratory results then can be transferred to real structures for (residual) lifetime predictions or safety analyses. Numerical simulations of experiments and, in particular, of structural parts are essential for the understanding of crack-tip deformation behavior. Theoretical and numerical tools can be used to derive approximate and simple formulas which can be used to calculate loading parameters.