FATIGUE ANALYSIS BASED ON FATIGUE FAILURE APPROACH AND DAMAGE TOLERANT APPROACH IN CORONARY STENT DESIGN

Abstract

Over the last few decades, cardiovascular stents have emerged as crucial biomedical devices. Stents undergo cyclic physiological loading, which can lead to progressive accumulation of structural damage over time eventually resulting in a stent fracture. Considering the critical role of stents, it is necessary to assess their fatigue endurance and predict a potential premature failure due to fatigue loading. This paper presents a comprehensive analysis of coronary stent design based on both fatigue failure and damage-tolerant approaches. Employing the fatigue failure approach, S-N analysis was conducted to pinpoint the critical zones of the stent. Initial resistance to fatigue was evaluated using Goodman's and Soderberg's criteria. These criteria were applied to principal and effective stresses obtained using the Finite Element Method. Susceptibility to fatigue damage was performed by simulating the initial crack growth, and it was assessed through the Paris power law. The damage-tolerant approach yields more conservative fatigue stress ranges compared to fatigue failure criteria, ensuring safety under standard physiological loading conditions. The presented approach offers reliable insights into stent durability, with potential for further enhancement.