Authors: Z Lin K Pike M Schlun A Zipse J Draper
Publish Date: 2012/09/25
Volume: 21, Issue: 12, Pages: 2628-2632
Abstract
Nitinol fatigue testing results are presented for variable strain amplitude cycling The results indicate that cycles smaller than the constant amplitude fatigue limit may contribute to significant fatigue damage when they occur in a repeating sequence of large and small amplitude cycles The testing utilized two specimen types stentlike diamond specimens and Zshaped wire specimens The diamond specimens were made from nitinol tubing with stentlike manufacturing processes and the Zshaped wire specimens were made from heat set nitinol wire The study explored the hypothesis that duty cycling can have an effect on nitinol fatigue life Stentlike structures were subjected to different in vivo loadings in order to create more complex strain amplitudes The main focus in this study was to determine whether a combination of small and large amplitudes causes additional damage that alters the fatigue life of a componentThis study was conducted with the support of a consortium of nitinol stent manufacturers Safe Technology Limited and Dassault Systèmes Simulia Corp The study was sponsored by Abbott Vascular Santa Clara CA USA The authors would like to thank Robert Boss for performing the fatigue test using stentlike diamond specimens Amar Kaur for preparing the Zshaped wire specimens and Radwan Hazime and Patrick Saxton for their contribution to this project
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