Article ID Journal Published Year Pages File Type
777076 International Journal of Fatigue 2008 13 Pages PDF
Abstract

A grain-level fatigue crack nucleation criterion for cold dwell in Ti-6242 alloy is developed in this paper using a rate and size dependent anisotropic elasto-crystal plasticity constitutive model, and validated with experiments. Early crack initiation in Ti-6242 under cold dwell fatigue has been identified to be caused by stress concentrations in a hard grain, induced by load shedding from creep in adjacent soft grains. Accurate prediction of local stress and strain evolution during loading requires a robust representation of morphological and crystallographic features of the microstructure. These are accounted for in the FE model in a statistically equivalent sense. The proposed crack nucleation model is based on the observed similarities between crack evolution at the tip of a crack and a dislocation pileup. The nucleation model is calibrated and validated using data available from acoustic microscopy though real time monitoring of crack evolution in dwell fatigue experiments.

Related Topics
Physical Sciences and Engineering Engineering Mechanical Engineering
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