Probabilistic Constant Fatigue Life Diagrams for Ceramics

Abstract

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 eff V , effective loading time f eff N t , 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 Si 3 N 4 subjected to rotating bending. The stress amplitude -the number of cycles to failure curves were then predicted for . この理論に基づき，種々のセラミックスを用いた様々 な破壊試験を通して，S- （ ：応力速度）線図，S-N 線図および S-t 線図の予測や SCG パラメータの評価が行