Optimization of Design Parameters of PLLA and PDLLA Stents Using FEM and RSM
| Autor: | Nurul Aulia Dewi |
|---|---|
| Rok vydání: | 2019 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 107 The stent is a tiny wire mesh tube one for treating patients with coronary heart disease. The stent performance is affected by the design of its strut and link. The material used to build the scaffold also affects its performance regarding the ability of a stent to expand due to the pressure test. This paper presents the optimization of a numerical result of a balloon expandable stent in responding to various inflated pressures. A 3D stent model is made with a size of 20 mm long and an outer diameter of 1.6 mm. It is tested with various inflated pressure by using finite element method (FEM) with Abaqus 6.13 software in order to obtain the mechanical performance such as von mises, radial recoil, longitudinal recoil, foreshortening, and inflated diameter. Simulations are performed on stents with various stent thickness of 50 µm, 75 µm, and 100 µm by using various inflated pressures. The simulation results are then optimized by using response surface method (RSM) with the parameters of stent thickness and inflated pressure. The results show that the optimal stent design is stent with a thickness of 50 µm and expansion pressure of 0.0273 MPa for PLLA. The responses generated from this optimal parameter are von mises of 64 MPa, radial recoil of 35.11%, longitudinal recoil of -3.52%, foreshortening of 4.43%, and an inflated diameter of 2.46 mm. While for PDLLA, the optimal result is a stent with a thickness of 50 µm and expansion pressure of 0.0141 MPa. The responses generated from this optimal parameter are von mises of 33 MPa, radial recoil of 19.54%, longitudinal recoil of -0.85%, foreshortening of 1.11%, and an inflated diameter of 2.29 mm. Based on the results, PLLA wins because it has better mechanical strength and degradation rate. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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