Dynamic finite element analysis of bioprosthetic heart valves with an experimentally derived material model.

摘要

In this study, we implement an experimentally derived material model for both planar and flexural deformations into FE analysis. Structural analysis investigations of BHV leaflets are performed through the FE implementation of the nonlinear anisotropic material model. Numerical simulations of BHV operation are then performed with the developed FE model for the opening and closing phases under physiological conditions.; A number of previous studies of BHV employing FE methods are reviewed. We investigate the significance as well as limitations of those previous studies and propose a new approach intended to the implementation of more realistic material models into the FE analysis of BHV. The basic concept of FE method is briefly described including FE formulations for nonlinear membrane-type structures. The importance of a realistic nonlinear material model and an appropriate element type in the FE analysis of soft tissue structures is emphasized. In this respect, it is proposed to perform the FE implementation of the most appropriate FE model for BHV leaflets based on experimental data. Bovine pericardial BHV leaflet specimens are utilized in the biaxial mechanical test and the experimental data are employed for the FE implementation of the nonlinear anisotropic material model for planar deformation. The three-point bending test with bovine pericardial BHV leaflet specimens is described and nonlinear bending moment-curvature relationships are obtained. A new material model determined by the experimentally determined nonlinear bending moment-curvature relationship is implemented into the FE code for flexural deformation. Then the flexural material model is combined with the previously developed planar model. The dynamic FE analysis of the pericardial BHV is performed and compared to the previously performed analyses. Contact element is introduced to simulate the comprehensive valve operation for the complete cardiac cycle since the closing phase includes the coaptation phenomenon between the leaflets. After we make conclusions and describe the limitations of the present study, several future studies are proposed as the last part.; The present study will make a contribution to the current computational approaches for developing new designs or improving the functional characteristics of BHV.