118 research outputs found

    Stress analysis in a layered aortic arch model under pulsatile blood flow

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    BACKGROUND: Many cardiovascular diseases, such as aortic dissection, frequently occur on the aortic arch and fluid-structure interactions play an important role in the cardiovascular system. Mechanical stress is crucial in the functioning of the cardiovascular system; therefore, stress analysis is a useful tool for understanding vascular pathophysiology. The present study is concerned with the stress distribution in a layered aortic arch model with interaction between pulsatile flow and the wall of the blood vessel. METHODS: A three-dimensional (3D) layered aortic arch model was constructed based on the aortic wall structure and arch shape. The complex mechanical interaction between pulsatile blood flow and wall dynamics in the aortic arch model was simulated by means of computational loose coupling fluid-structure interaction analyses. RESULTS: The results showed the variations of mechanical stress along the outer wall of the arch during the cardiac cycle. Variations of circumferential stress are very similar to variations of pressure. Composite stress in the aortic wall plane is high at the ascending portion of the arch and along the top of the arch, and is higher in the media than in the intima and adventitia across the wall thickness. CONCLUSION: Our analysis indicates that circumferential stress in the aortic wall is directly associated with blood pressure, supporting the clinical importance of blood pressure control. High stress in the aortic wall could be a risk factor in aortic dissections. Our numerical layered aortic model may prove useful for biomechanical analyses and for studying the pathogeneses of aortic dissection

    Localization of bypass-induced changes in flow in coronary artery models

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    1249-1252<span style="font-size:14.0pt;line-height: 115%;font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" color:#767676;mso-ansi-language:en-in;mso-fareast-language:en-in;mso-bidi-language:="" hi"="" lang="EN-IN">Right coronary artery by pass restores blood flow through heart tissues. This also induces changes in flow leading to its failure. By this work the sites which are prone to such changes are localized. The bypass models are developed from transparent silicon rubber of elastic properties similar to arterial tissues. Flow visualization is carried out by photoelasticity technique by using dilute solution of vanadium pentoxide. This analysis carried out under pulsatile flow conditions shows that the proximal stenotic region continues to contribute to the alteration in flow in the hood region of the bypass. Thus making its proximal and distal regions prone to flow-induced changes, which may lead to its blockage over the long duration.</span

    Flow Studies in True-to-Scale Models of Human Renal Arteries

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    Effects of Phase Relationships on Wall Shear Stress in Curved and Straight Elastic Artery Models

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