Mechanical Analysis Of Bioprosthetic Heart Valve With Nonlinear Material Based On Fluid-structure Interaction

The human heart provides the necessary power to the body’s blood circulation. The valves in the human heart ensures that the blood flows only in the forward direction by opening during the forward flow phase. During a cardiac cycle, the leaflets undergo complex deformation, and the blood flow past these valves is also highly three-dimensional. That makes the valve lesions occur easily. Now effective treatment for diseased valves is valvular replacement with prosthetic heart valves. Bioprosthetic heart valve has excellent hemodynamic performance and low rate of plugging thrombosis. It also don’t need a life-time of anticoagulant, but the durability of these implants is still a significant problem.In this paper, four types of the valve leaflets are designed based on the heart mechanics, membrane and the bionics, then the geometrical parametric models of the spherical, ellipsoidal, cylindrical, paraboloidal leaflets and the arterial wall are established by using the Pro/E software. The fluid-structure coupling model of valve and blood are established using ANSYS software. The dynamic properties of the valve leaflets with different models, thicknesses and material characteristics are analyzed and compared. It provides the theoretical foundation for the further design of high performance valve.In this paper, the dynamic properties of valve leaflets with different models are analyzed and compared based on the finite element method. The analysis results show that the stress distribution of valve leaflets with different material properties is approximately the same. But the maximum stress of valve leaflets with nonlinear material is slightly higher than valve leaflets with linear material. The stress concentration area mainly appears in the intersection area of free edge and suture edge, no matter what kind of material is. But the stress concentration of valve leaflets with nonlinear material is more obvious, thus the stress distribution of valve leaflets with nonlinear material is more close to the real situation. All type of the valve leaflet appear the phenomenon of uneven stress distribution and stress concentration area. The cylindrical leaflet have poor mechanical properties, The spherical, paraboloidal, ellipsoidal leaflet has their advantages in different aspect. The spherical leaflet with 0.45mm leaflet thickness and the paraboloidal leaflet with 0.4mm leaflet thickness have better mechanical properties. Based on fluid-structure coupling theory, we use the finite element software for fluid-structure interaction dynamics simulation of valve leaflets, and the dynamic properties of valve leaflets with different parameters are analyzed and compared. These results can be used as a reference for improving the long-term durability and manufacturing of the bioprosthetic heart valve.