本文選題：生物瓣膜 + 計算機輔助設(shè)計�。� 參考：《山東大學》2015年碩士論文

【摘要】：心臟是為人體血液循環(huán)提供必要動力的裝置,而心臟瓣膜是保證血液按一定方向流動的控制原件。在一個心動周期中,瓣葉要經(jīng)歷復雜的形變以及流過瓣膜的血液量也很高,這使得瓣膜易發(fā)生病變。目前有效治療瓣膜疾病的手段為心臟瓣膜置換術(shù)。生物瓣膜與天然心臟瓣膜相似,流場特性接近天然心臟瓣膜,具有較好的血流動力學性能,不需要終身服用抗凝藥物,造成血栓栓塞的幾率低等優(yōu)點,但患者置換心臟瓣膜后,由于生物瓣膜的鈣化和撕裂使心臟瓣膜損壞從而降低瓣膜的使用壽命,提高生物瓣膜的耐久性是生物瓣膜研究領(lǐng)域亟待解決的問題。本文以心臟流體力學為理論依據(jù),根據(jù)生物瓣膜的設(shè)計原則,對生物瓣膜進行參數(shù)化設(shè)計,運用三維建模軟件構(gòu)建了瓣膜瓣葉及動脈壁的三維實體模型。在有限元軟件中構(gòu)建生物瓣膜與血液的流固耦合模型,針對不同瓣葉材料特性、不同瓣葉型面以及不同瓣葉厚度的生物瓣膜進行流固耦合動力學模擬,分析對比幾種不同參數(shù)對生物瓣膜力學性能的影響,為進一步設(shè)計性能優(yōu)良的生物瓣膜提供理論基礎(chǔ)。本文利用計算機軟件對生物瓣膜在不同參數(shù)下進行動力學模擬分析。分析結(jié)果表明,不同材料特性的瓣葉,其應力分布基本相同,但非線性材料瓣葉的應力最大值略高于線性材料瓣葉。應力集中區(qū)域均主要位于結(jié)合邊與縫合邊的交界處,非線性材料瓣葉應力集中更明顯,在結(jié)合邊與縫合邊交界處的等值線較為密集,這更加貼近瓣葉真實的應力分布情況；四種型面瓣葉都出現(xiàn)了不同程度的應力分布不均勻現(xiàn)象,應力集中區(qū)域略有不同。圓柱面在各方面的力學性能均較差,而旋轉(zhuǎn)拋物面、圓球面和橢球面在不同方面有著各自的優(yōu)勢；圓球型面與旋轉(zhuǎn)拋物型面瓣葉的厚度分別為0.45mm與0.4mm時具有較好的動態(tài)力學性能。本文以天然心臟瓣膜相關(guān)理論為依據(jù),利用有限元軟件針對生物瓣膜進行流固耦合動力學模擬,分析不同參數(shù)下的瓣膜動態(tài)力學性能的影響,并對它們進行分析對比,從而進一步優(yōu)化瓣膜的力學性能,為提高生物瓣的耐久性提供了可靠依據(jù)。
[Abstract]:The heart is a device that provides the necessary power for the circulation of human blood, and the heart valve is the control element to ensure the blood flow in a certain direction. In a cardiac cycle, the valve leaves undergo complex deformation and high blood flow through the valve, which makes the valve prone to pathological changes. Valvular replacement is the effective treatment of valvular disease. The biological valve is similar to the natural heart valve, the flow field characteristic is close to the natural heart valve, has the good hemodynamic performance, does not need to take the anticoagulant drug for life, causes the thromboembolism probability and so on low, but after the patient replacement heart valve, Because of the calcification and tear of biological valve, the damage of heart valve can reduce the service life of valve, and improve the durability of biological valve is an urgent problem to be solved in the field of biological valve research. Based on the theory of cardiac fluid mechanics and according to the design principle of biological valve, the parameterized design of biological valve was carried out in this paper, and the three-dimensional solid model of valve lobe and arterial wall was constructed by using three-dimensional modeling software. The fluid-solid coupling model of biological valve and blood was constructed in finite element software. The fluid-solid coupling dynamics of biological valve with different valve material characteristics, different valve leaf profile and different leaf thickness were simulated. The effects of different parameters on the mechanical properties of biological valves are analyzed and compared to provide a theoretical basis for the further design of biological valves with excellent performance. In this paper, a computer software is used to simulate the dynamics of biological valves under different parameters. The results show that the stress distribution of the leaves with different material characteristics is basically the same, but the maximum stress of the nonlinear material leaves is slightly higher than that of the linear ones. The stress concentration region is mainly located at the junction between the combined edge and the suture edge, and the stress concentration of the nonlinear material flap is more obvious, and the isoline at the junction between the combined edge and the suture edge is more dense, which is closer to the true stress distribution of the lobe. The stress distribution was uneven in all the four types of flaps, and the stress concentration region was slightly different. The mechanical properties of the cylindrical surface are poor in all aspects, while the rotating paraboloid, the spherical surface and the ellipsoidal surface have their own advantages in different aspects. When the thickness of spherical and rotating parabolic lobes is 0.45mm and 0.4mm, respectively, they have better dynamic mechanical properties. Based on the theory of natural heart valve, the fluid-solid coupling dynamics of biological valve was simulated by finite element software. The effects of different parameters on the dynamic mechanical properties of the valve were analyzed and compared. Thus, the mechanical properties of the valves are further optimized, which provides a reliable basis for improving the durability of the biological valves.
【學位授予單位】：山東大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：R654.2

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本文編號：2027971