Higher-order asymptotic crack-tip fields in a power-law creeping material

The higher-order asymptotic crack-tip fields are considered for a mode-I crack in a power-law creeping material under the plane strain conditions. Based on the three-term solution of Yang et al. (1993) and Chao et al. (1994) for hardening materials, this paper develops a three-term solution near a crack tip in creeping materials only with two parameters: C(t)-integral and a constraint parameter A(2)(t) This solution is then discussed for conditions of small-scale creep, transient creep and extensive creep. In addition, detailed finite element analysis is performed for four specimens, namely, single-edge notched tension, three point bend, center-cracked panel and compact tension. Good agreement, in both angular and radial stresses, with finite element results confirms that the three-term asymptotic solution is universally valid for specimens possessing various crack-tip constraints and from small-scale creep to extensive creep. This statement is especially true fur shallow cracked (or low constraint) specimens, where the dominant region for the HHR-type singularity does nut practically exit. (C) 2001 Elsevier Science Ltd.,LVI rights reserved.