Numerical Simulation of Self-Expanded NitinolBased Shape Memory Alloy Stent

Shape memory alloy has self-expansion capability to act as a stent in the medical application. It does not require the insertion and inflation of a balloon system to give them the desired shape. The finite element simulation has been done for the SMA stent at low stress levels. The SMA stent is prepared with a dimension more than the desired artery value. Due to the change in temperature, the SMA has the ability to adopt with the body temperature. The material partially transforms from austenite to martensite phase at low stress levels. The yield stress increases, so the force applied by the stent on the inner of the artery increases. After crimping, the stress is concentrated at the infer face of the bend. Comparing the phase change results that heating to body temperature of SMA has two effects: The maximum stress becomes far higher because the limit stress has increased and has the zone of transformation has reduced that reverse transformation has partially occurred.