Randomization method of deterministic equation for probability fracture mechanics

In order to obtain any probability of survival for crack growth life, a randomization method of deterministic equation for probability fracture mechanics is presented. According to this method, the deterministic equation of fracture mechanics is randomized to stochastic equation, and the parameters of the stochastic equation are estimated by means of the statistics. Three new kinds of random models to gain the p-da/dN-ΔK curve and the γ-p-da/dN-ΔK curve (confidence level-probability of survival-fatigue crack growth rate-stress intensity factor range curve) are proposed by using this randomization method. And the p-da/dN-ΔK curves and the γ-p-da/dN-ΔK curves determined by these three models are discussed and compared according to the treatment result of the experimental data from CT specimens. From examples, it is found that the three deterministic fatigue crack growth rate equations determined by these models are very near and in agreement with the traditional deterministic fatigue crack growth rate equation, and these models are effectively and easily used to treat fatigue crack growth rate data.