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標題: | 提升自動擴張式血管支架疲勞壽命之創新設計 A Novel Design Concept to Enhance Pulsatile Fatigue Life of Self-Expanding Stents |
作者: | Ming-Ting Yin 鄞名廷 |
指導教授: | 蕭浩明(Hao-Ming Hsiao) |
關鍵字: | 自動擴張式血管支架,心血管疾病,有限元素分析,脈動疲勞壽命,Goodman 疲勞壽命分析, Self-expanding stent,Vascular disease,Finite element analysis,Pulsatile fatigue life,Goodman fatigue life analysis, |
出版年 : | 2013 |
學位: | 碩士 |
摘要: | 自動擴張式血管支架現今被廣泛地運用在治療周邊動脈阻塞等疾病。然而當支架安裝於人體之後,必須承受血管對其施加的各種壓迫;尤其以血液脈搏之周期性壓力變化而產生的徑向變形更是支架無可避免之負擔。若支架因此而發生疲勞破壞,甚至造成支架結構斷裂,除了將失去支撐血管的能力外,更有可能對血管造成進一步的傷害。本文中提出一項創新的支架設計概念,目的為增進自動擴張式血管支架對抗疲勞破壞的能力。此設計概念的原理是藉由調整支架之幾何形狀,漸進地削弱支架結構的強度,將支架所承受之集中應力/應變往原本承擔較低負載的區域分散。為分析此支架設計對於疲勞強度的提升效果以及檢驗此設計是否會造成支架其他重要性質之犧牲,本文中以有限元素模擬搭配 Goodman 疲勞壽命分析對血管支架做量化的分析與比較。由分析結果證實此設計概念在以簡單的幾何形狀實現後便可將支架的疲勞安全係數大幅提升至 2.5 倍,而在進行幾何細節上的優化後甚至可以再次將疲勞安全係數提升至 5 倍之多。本文中所提出之設計在增進支架疲勞強度的同時也擁有相較於傳統設計更優的徑向強度,且不會犧牲支架的管徑大小與支撐能力。此研究結果為血管支架之設計提供極具潛力的方向,可作為未來提升支架疲勞抗性研究之基石。 Self-expanding stent has been widely used for the treatment of peripheral artery occlusions. However, the implanted stents are exposed to a variety of oppressions. The cyclic radial deformation caused by pulsatile blood pressure is inevitable and may cause long-term fatigue failure on stent structure. Once the fatigue failure occurred, the broken stent strut will lose the ability to support blood vessel and may cause further damage to vessel wall. In this thesis, a novel stent design concept of enhancing stent fatigue resistance is introduced. The concept of this design is to narrow the stent strut width gradually, redistribute the concentrated stress/strain to the low burden area on the strut. In order to evaluate the performance of this design, a finite element model is developed to simulate the vessel environment and provide strain state of stent for Goodman fatigue life analysis. Result shows that the fatigue safety factor is rapidly increased to 2.5 times that of the original stent due to this design, and even boosted to 5 times when the strut geometry was modified. The design concept enhanced stent fatigue safety factor while the stent radial strength, profile and scaffolding are not compromised as the traditional designs. The achievement done in this thesis provides a promising concept for stent design on improving fatigue performance. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/62373 |
全文授權: | 有償授權 |
顯示於系所單位: | 機械工程學系 |
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