Safety performance of self-expandable NiTi alloy stent.
10.7507/1001-5515.201907039
- Author:
Zhiguo LI
1
;
Wengang YAN
1
;
Haiquan FENG
1
Author Information
1. Engineering Graphics Department, School of Mechanical Engineering, Inner Mongolia University of Technology, Hohhot 010051, P.R.China.
- Publication Type:Journal Article
- Keywords:
dynamic safety factor;
fatigue life;
fatigue strength;
finite element analysis;
stents
- MeSH:
Alloys;
Finite Element Analysis;
Nickel;
Reproducibility of Results;
Self Expandable Metallic Stents;
Stress, Mechanical;
Titanium
- From:
Journal of Biomedical Engineering
2020;37(2):334-339
- CountryChina
- Language:Chinese
-
Abstract:
In order to evaluate the safety performance of self-expandable NiTi alloy stents systematically, the dynamic safety factor drawn up by International Organization for Standardization, was used to quantitatively reflect the safety performance of stents. Based on the constitutive model of super-elastic memory alloy material in Abaqus and uniaxial tensile test data of NiTi alloy tube, finite element method and experiments on accelerated fatigue life were carried out to simulate the self-expansion process and the shape change process under the action of high and low blood pressure for three -type stents of 8×30 mm, 10×30 mm, 12×30 mm. By analyzing the changes of stress and strain of self-expanding NiTi alloy stent, the maximum stress and strain, stress concentration position, fatigue strength and possible failure modes were studied, thus the dynamic safety factor of stent was calculated. The results showed that the maximum stress and plastic strain of the stent increased with the increase of grip pressure, but the maximum stress and strain distribution area of the stent had no significant change, which were all concentrated in the inner arc between the support and the connector. The dynamic safety factors of the three stents were 1.31, 1.23 and 1.14, respectively, which indicates that the three stents have better safety and reliability, and can meet the fatigue life requirements of more than 10 years, and safety performance of the three stents decreases with the increase of stent's original diameter.
