Peer-Reviewed Journal Details
Mandatory Fields
Grogan, JA,Leen, SB,McHugh, PE
2013
April
Journal Of The Mechanical Behavior Of Biomedical Materials
Influence of statistical size effects on the plastic deformation of coronary stents
Published
()
Optional Fields
Finite elements Crystal plasticity Metallic microstructures Stents THIN METAL SHEETS GRAIN-SIZE STRESS-STRAIN POLYCRYSTAL PLASTICITY TENSILE PROPERTIES STAINLESS-STEEL BEHAVIOR FATIGUE STRUTS MODEL
20
61
76
The dimensions of coronary stent struts are similar to those of the metallic grains of their constituent alloys. This means that statistical size effects (SSEs), which are evident in polycrystals with few grains through their dimensions, can have detrimental effects on the mechanical performance of stent struts undergoing large plastic deformation. Current trends in coronary stent design are towards thinner struts, potentially increasing the influence of SSEs. In order to maintain adequate device performance with decreasing strut thickness, it is therefore important to assess the role of SSEs in the plastic deformation of stents. In this study, finite element modelling and crystal plasticity theory are used to investigate SSEs in the deformation of struts in tension and bending. The relationships between SSEs and microstructure morphology, alloy strain hardening behaviour and secondary phases are also investigated. It is predicted that reducing the number of grains through the strut cross section and increasing the number of grains along the strut length have detrimental effects on mechanical performance. The magnitudes of these effects are predicted to be independent of the uniformity of the studied microstructures, but dependent on alloy strain hardening behaviour. It is believed that model predictions will aid in identifying a lower bound on suitable strut thicknesses in coronary stents for a range of alloys and microstructures. (C) 2012 Elsevier Ltd. All rights reserved.
10.1016/j.jmbbm.2012.12.008
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