PREDICTION AND STATISTICAL ASPECTS OF MULTIAXIAL FATIGUE LIFE IN NOTCHED COMPONENTS BY CRACK GROWTH SIMULATION

摘要

A proper life assessment for machine components, which are subjected to complex stresses, requires an analytical procedure that can adequately deal with effects of microstructure as well as stress multiaxiality on crack growth. In this work, a modelling procedure is developed which is applicable to crack growth in notched components under multiaxial fatigue for materials with different microstructures. A microstructure is modelled as an aggregate of hexagons, and a competition is proposed to describe crack growth in the modelled microstructure. Results simulated by using the developed model are compared with experimental results in fatigue tests conducted using notched specimens of four kinds of materials. It is found that cracking morphology and its related failure life in a notched specimen are well simulated by a Monte Carlo procedure based on the model. Statistical properties of the failure life in multiaxial fatigue are also clarified by the simulation.