Peer-Reviewed Journal Details
Mandatory Fields
Grogan, J.A., Leen, S.B., McHugh, P.E.
Journal Of Mechanical Behaviour Of Biomedical Materials
The influence of statistical size effects on the plastic deformation of coronary stents.
Optional Fields
Finite elements Crystal plasticity Metallic microstructures Stents
The dimensions of coronary stent struts are similar to those of the metallic grains of theirconstituent alloys.This means that statistical size effects (SSEs), which are evident inpoly crystals with few grains through their dimensions,can have detrimental effects on themechanical performance of stent struts undergoing large plastic deformation.Currenttrends in coronary stent design are towards thinner struts, potentially increasing theinfluence of SSEs. In order to maintain adequate device performance with decreasing strutthickness, it is therefore important to assess the role of SSEs in the plastic deformation ofstents. In this study, finite element modelling and crystal plasticity theory are used toinvestigate SSEs in the deformation of struts in tension and bending.The relationshipsbetween SSEs and micro structure morphology,alloy strain hardening behaviour andsecondary phases are also investigated. It is predicted that reducing the number of grainsthrough the strut cross section and increasing the number of grains along the strut lengthhave detrimental effects on mechanical performance. The magnitudes of these effects arepredicted to be independent of the uniformity of the studied micro structures,butdependent on alloy strain hardening behaviour. It is believed that model predictions willaid in identifying a lower boundon suitable strut thicknesses in coronary stents for a rangeof alloys and micro structures.
Grant Details
project funding through an ICRSET fellowship through the EMBARK initiative
Publication Themes