Higher order C(t)-Tz-AT solution for three-dimensional creep crack border fields

A higher order C(t)-T-z-A(T) solution is developed for power-law creeping solids on the basis of the C(t)-A(2)(t) and C(t)-T-z solutions. Validations against comprehensive 3D FE analysis results in specimens with through-thickness, corner, surface and embedded cracks show that the developed C(t)-T-z-A(T) solution can provide an accurate description of the 3D crack border stress fields in all the simulated conditions. At small-scale and large-scale creep stages, the absolute value of in-plane constraint coefficient AT is within 0.05 in the SECT, CT and SENB specimens, which indicates that the higher order C(t)-T-z-A(T) solution could degenerate into the C(t)-T-z solution in such high constraint specimens. However, in CCT and part-through cracked specimens, the absolute value of A(T) may increase remarkably with creep time, and the C(t)-T-z-A(T) solution is necessary. Based on the numerical results, a set of explicit empirical formulae of T-z are obtained for all the specimens, and the detailed values of A(T) are listed in Appendix.