FINITE ELEMENT ANALYSIS ON NITINOL MEDICAL APPLICATIONS

摘要

Nitinol, an alloy of about 50% Ni and 50% Ti, is a very unique material. At constant temperature above its Austenite finish (A_f) temperature, under uniaxial tensile test, the material is highly nonlinear and capable of large deformation to the ultimate strain on the order of 15%. This material behavior, known as superelasticity, along with its excellent biocompatibility and corrosion resistance, makes Nitinol a perfect material candidate for many medical device applications. However, the nonlinear material response also requires a specific material description to perform the stress analysis. The user developed material subroutine from HKS/West makes the simulation of the Nitinol devices possible. This article presents two case studies of the nonlinear finite element analysis using ABAQUS/Standard and the Nitinol UMAT.