Micro-scale testing and micromechanical modelling for high cycle fatigue for CoCr stent material

Sweeney, CA, O'Brien, B, Dunne, FPE, McHugh, PE, Leen, SB. (2015) 'Micro-scale testing and micromechanical modelling for high cycle fatigue for CoCr stent material'. Journal Of Mechanical Behavior Of Biomedical Materials, 46 :244-260.

Abstract

This paper presents a framework of experimental testing and crystal plasticity micromechanics for high cycle fatigue (HCF) of micro-scale L605 CoCr stent material. Micro-scale specimens, representative of stent struts, are manufactured via laser micro-machining and electro-polishing from biomedical grade CoCr alloy foil. Crystal plasticity models of the micro-specimens are developed using a length scale-dependent, strain-gradient constitutive model and a phenomenological (power-law) constitutive model, calibrated from monotonic and cyclic plasticity test data. Experimental microstructural characterisation of the grain morphology and precipitate distributions is used as input for the polycrystalline finite element (FE) morphologies. Two microstructure-sensitive fatigue indicator parameters are applied, using local and non-local (grain-averaged) implementations, for the phenomenological and length scale-dependent models, respectively, to predict fatigue crack initiation (FCI) in the HCF experiments.

Funder

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Publisher

Elsevier ScienceDirect

Rights

Attribution-NonCommercial-NoDerivs 3.0 Ireland

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Collections

Biomedical Engineering (Scholarly Articles)