Low Cycle Fatigue Study of AISI 316L Cardiovascular Stent for Two Different Designs

Abstract

The main originality of this work consists in investigating low cycle fatigue of AISI 316L cardiovascular stents under hypertensive loading. For this purpose, two geometries of stents are expanded to various diameters and subjected to hypertensive blood pressure. Based on a combination between the fatigue parameter of Jiang-Sehitoglu and the relationship of Coffin-Manson, a numerical model for the prediction of the number of cycles to crack failure is developed. The stent is found to exhibit a fatigue life reduction with the increase of the expansion diameter due to ratchetting strain. In addition, the location of the failure is independent on the design. However, the U-shape strut permits a better distribution of pressure over the stent strut resulting in a longer fatigue life as compared to the Ω-shape.