抄録
In this study, crack propagation is regarded as a successive random walk process. Two Markovian models of crack growth described by the Fokker-Planck equation are introduced through Paris-Erdogan's law, and the crack length distribution at any fatigue cycle and the life distribution at any crack length are set up analytically with some approximations.
The first model is expressed by the Fokker-Planck equation with constant coefficients, which are calculatable from the crack propagation data, and another model is introduced theoretically from the distribution of the coefficient of Paris-Erdogan's equation directly.
These Fokker-Planck equations are analysed by the Lax-Wendroff scheme, one of the finite-difference methods. As a result, the crack-length distribution in random stress sequences is evaluated successfully.
