X. Y. Gong, Medical Implant Mechanics LLC, Aliso Viejo, CA; Y. Jiang, University of Nevada, Reno, NV
Nitinol fatigue remains unclear and confusing years after the material has been successfully used in medical implant industry. It is unique sue to the high nonlinearity of the material responses and it is also difficult due to the material forms that were wide used in the medical implant industry such as thin and small tubings or fine wires. These motivate the authors to review the literatures and provide perspectives that can link the basic material behaviors and fatigue mechanisms. Both total life and flaw tolerant approach are reviewed and discussed in this article with additional proposals that lead further studies to better understand the material characteristics for a refined predictive method.
Summary: Nitinol fatigue is unique due to its nonlinear material properties. It is also difficulty due to the forms of the material used in medical implant applications such as small and thin tubings and fine wires. Despite there are reasonable amount of research on the subject, there are many different opinions and conclusions that are sufficient to cause confusions in the field. This article reviews the literatures on this topic and provides perspectives that links the material knowledge and the mechanism associated with the fatigue characteristics.
