Impact of microstructural heterogeneity on crack path trajectories under fretting fatigue loading
Reza Talemi, KU Leuven, Belgium
Fretting, a phenomenon characterized by the relative, oscillatory, tangential movement of two contacting bodies with minute displacement amplitudes, is known to induce high cyclic stresses and surface damage. When coupled with fluctuating bulk loading, it gives rise to fretting fatigue, a process that affects crack initiation and propagation due to the resulting surface damage, ultimately reducing the lifespan of affected components. The material and its microstructure play a crucial role in influencing the response to fretting fatigue. This study specifically investigates the impact of microstructural heterogeneity at and near the contact interface on crack propagation behaviour.
In this research, extended finite element modelling (XFEM) is employed in conjunction with the Smith-Watson-Topper (SWT) fatigue parameter to simulate crack propagation under multiaxial, non-proportional loading conditions. The outcomes of the study underscore the effectiveness of the proposed model in replicating the variation in crack paths resulting from microstructural heterogeneity. Notably, a distinct scattering of crack paths has been observed, with the degree of scattering increasing proportionally with higher levels of bulk stress. These observations reveal that propagating cracks tend to deflect when they encounter grains with substantial disparities in their elasto-plastic properties, whereas they exhibit smoother propagation through grains characterized by similar strength characteristics.
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