On higher-order crack-tip fields in creeping solids

In view of the near-tip constraint effect imposed by the geometry and loadi ng configuration, a creep fracture analysis based on C* only is generally n ot sufficient. This paper presents a formulation of higher-order crack-tip fields in steady power-law creeping solids which can be derived from an asy mptotic development of near-tip fields analogous to that of Sharma and Arav as and Yang et al. for elastoplastic bodies. The higher-order fields are co ntrolled by a parameter named A(2)*, similar as in elastoplasticity, and a second loading parameter, sigma (infinity). By means of the sealing propert ies for power-law materials, it is shown that A(2)(*) for a flat test speci men is independent of the loading level. Finally, we carry out small-strain finite element analyses of creep in single-edge notched tension, centered crack panel under tension, and single-edge notched bending specimens in ord er to determine the corresponding values of A(2)* for mode 1 cracks under p lane-strain conditions.