The variation of crack energy density (CED) on creep crack growth

Creep crack growth (CCG) rate has been organized frequently by C* or C-t parameter However, crack behavior of early stage under unsteady state condition has not been explained. Crack energy density (CED), which has been proposed as a parameter that can provide a unified description of crack behavior with no restriction on constitutive equation, can give the general expression about creep crack growth rate. By applying C-t and the concept of CED to the results, we showed that creep crack growth rate for all ranges of creep can be explained in a unified way by CED and its derivatives. Moreover, the physical meaning of the C-t is clarified in the discussion.