نوع مقاله : مقاله کامل پژوهشی

نویسندگان

1 دانشجوی دکترا، دانشکده‌ی مهندسی پزشکی، دانشگاه صنعتی سهند، تبریز، ایران

2 استاد، دانشکده‌ی مهندسی پزشکی، دانشگاه صنعتی سهند، تبریز، ایران

3 دانشیار، دانشکده‌ی مهندسی پزشکی، دانشگاه صنعتی سهند، تبریز، ایران

4 دانشیار، دانشکده‌ی مهندسی پزشکی، دانشگاه صنعتی امیرکبیر، تهران، ایران

10.22041/ijbme.2022.538149.1719

چکیده

هندسه‌ی لت‌ها در طراحی دریچه‌های مصنوعی نقش مهمی ایفا می‌کند. یک دریچه‌ی مناسب از لحاظ عمل‌کردی باید سطح روزنه‌ی هندسی بالایی داشته باشد و حداقل برگشت جریان خون در آن اتفاق افتد. در این مقاله با در نظر گرفتن منحنی شعاعی و منحنی لبه‌ی آزاد لت‌ها به عنوان پارامترهای هندسی، تعدادی دریچه طراحی شده و هندسه‌ی لت‌ها برای یکی از مدل‌ها بر اساس یک منحنی شعاعی پیشنهادی پیاده‌سازی شده که این منحنی شامل دو خط راست و قوسی واقع شده در بین آن‌ها است. خواص مکانیکی پلیمر پلی‌استایرن به لت‌ها اختصاص داده شده و مدل هایپرالاستیک مونی-ریولین برای توصیف رفتار مکانیکی پلیمر به کار برده شده است. با استفاده از روش المان محدود، پارامترهایی مانند بیشینه‌ی سطح روزنه‌ی هندسی، سطح روزنه‌ی هندسی باقی‌مانده در حالت بسته، تنش فون-میزس و به‌هم‌رسی لت‌ها در حالت کاملا باز و بسته‌ی دریچه‌ها ارزیابی شده است. نتایج به دست آمده برای دریچه‌ها با هم مقایسه شده و نشان داده شده که دریچه‌ی با منحنی شعاعی پیشنهادی عمل‌کرد بهتری داشته است. بیشینه‌ی سطح روزنه‌ی هندسی 1/69%، عرض به‌هم‌رسی 6/2 میلی‌متر و تنش بیشینه‌ی فون-میزس 921/0 مگاپاسکال در حالت بسته و 731/0 مگاپاسکال در حالت باز ثبت شده است. اهمیت منحنی شعاعی در طراحی هندسه‌ی لت‌ها و به ویژه در به‌هم‌رسی کاملا مشهود بوده و هر چه این منحنی به سمت خط راست تمایل پیدا کند سطح روزنه‌ی هندسی افزایش یافته و در مقابل به‌هم‌رسی لت‌ها ضعیف می‌شود. طرح پیشنهادی منحنی شعاعی، تعادلی بین این دو پارامتر برقرار کرده است. 

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Study of Leaflet Radial Curve Effect on Polymeric Valve Performance by Finite Element Method

نویسندگان [English]

  • Nima Sarrafzadeh Ghadimi 1
  • Farzan Ghalichi 2
  • Hanieh Niroomand-Oscuii 3
  • Nasser Fatouraee 4

1 Ph.D. Student, Biomedical Engineering Department, Sahand University of Technology, Tabriz, Iran

2 Professor, Biomedical Engineering Department, Sahand University of Technology, Tabriz, Iran

3 Associate Professor, Biomedical Engineering Department, Sahand University of Technology, Tabriz, Iran

4 Associate Professor, Biomedical Engineering Department, Amirkabir University of Technology, Tehran, Iran

چکیده [English]

Geometries of leaflets play an important role in designing prosthetic valves (PVs). A valve must have a high geometric orifice area (GOA) and low regurgitation to function properly. In this paper, some polymeric tri-leaflet valves were designed based on radial and free edge curves of previous designs and together with them a new radial curve, which consists of two lines and an arc between them was proposed. Mechanical properties of polystyrene polymer are assigned to leaflets using the Mooney-Rivlin hyperelastic model. The finite element method (FEM) has been utilized to evaluate GOA, regurgitation, von Mises stress, and leaflets' coaptation in a fully closed and opened state. Results were compared, and the valve with the proposed leaflet geometry exhibited better performance among all valves. 69.1% GOA, 2.6 mm coaptation width, 0.921 MPa von Mises stress for closed-form, and 0.731 MPa von Mises stress for opened form were recorded. The significance of the radial curve in designing the geometry of leaflets has been revealed especially on the case of leaflets' coaptation. The more this curve tends to a straight line the higher the geometric orifice area and the weaker the coaptation. The proposed curve establishes an equilibrium between these two parameters.

کلیدواژه‌ها [English]

  • Polymeric Valve
  • Geometric Design
  • Radial Curve
  • Coaptation
  • Geometric Orifice Area
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