セラミックスに対する確率論的等疲労寿命線図

抄録

This paper presents a probabilistic model for predicting the constant fatigue life (CFL) diagrams for ceramics. First, a unified probabilistic delayed-fracture (PDF) model was proposed on the basis of the slow crack growth (SCG) concept in conjunction with the two-parameter Weibull distribution. Second, probabilistic CFL diagrams for effective volume V_eff, effective loading time t_effN_f, fracture probability F and stress ratio R were obtained using the PDF model. The probabilistic CFL diagram was then related with the modified Goodman's diagram. Third, the unified strength parameters associated with the PDF model were determined using the experiment data of Si₃N₄ subjected to rotating bending. The stress amplitude - the number of cycles to failure curves were then predicted for R=-1 and 0 and various values of F. Moreover, the probabilistic CFL diagrams for various values of V_eff and t_effN_f at F were depicted using the unified strength parameters. The validity of the present model was confirmed through the comparison of the predicted CFL diagrams with the experiment data.