Development of Micro-mechanical Models of Fatigue Damage
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Accumulation of fatigue damage in high and low cycle regimes is largely associated with nucleation and development of irreversible plastic deformations and voids. The effect of these microstructural changes on conventional (second-order) elastic constants is typically very small, which makes experimental evaluation of the progressive fatigue damage accumulation difficult and the classical damage theories inapplicable. It was demonstrated in the past that the third-order elastic constants are sensitive to fatigue damage and these material constants can be evaluated using various ultrasonic techniques. The ultimate aim of this study is to develop micro-mechanical models, which link the micro-porosity and micro-plastic deformations, to the effective third-order elastic constants of the material. These models could provide a foundation for the evaluation of early fatigue damage, i.e. the damage prior formation of a micro-defect (crack), as well as the remaining fatigue life of structures.
KeywordsFatigue damage Third-Order Elastic Constants Finite elasticity
This work was supported by the Australian Research Council through DP160102233, LE170100079, DP200102300 and the Australian Research Training Program Scholarship. Their support is greatly appreciated.