Behavior of Creep Crack Growth and Its Simulation from the Standpoint of Crack Energy Density

Abstract

The general condition by which the rate of crack growth is controlled is discussed based on the concept of crack energy density ε, and especially the parameters of creep crack growth rate are proposed. That is, it is shown that the average values of ∂^^ε_t/∂t and ∂^^εx_l/∂X, concerning ε which correspond to the increase rate and the gradient of ε at the crack tip respectively are the parameters of creep crack growth rate based on the creep crack model in which a crack extends discontinuously with respect to time. Moreover, the crack growth of a center notched specimen in tensile creep under plane stress condition is simulated by means of finite element method. In the analysis, the condition of constant εc (critical value of ε) is used. The applicabilities of ∂^^ε_t/∂t and ∂^^εx_l/∂X as parameters of creep crack growth are numerically verified through this analysis.