APPLICATION OF MICROSTRUCTURE-BASED FATIGUE MODELS TO COMPONENT LIFE PREDICTION

摘要

This paper summarizes the development of a set of microstructure-based fatigue crack initiation and growth models for probabilistic life-prediction of structural components. Microstructural parameters that impact fatigue crack initiation and growth lives are identified and incorporated explicitly into the response equations. Fatigue life variability due to microstructure variation is then treated via a probabilistic approach. Applications of these microstructure-based fatigue models to predicting the variability of fatigue crack initiation and growth response of the Ni-based superalloy, IN 718, are demonstrated and compared against experimental data. The use of the information on the crack size and da/dN variabilities in probabilistic design and lifing of structural components is illustrated by numerical simulations.