Numerical models for the simulation of flexible artificial heart valves: part I--computational methods

Area of Science:

• Computational fluid dynamics
• Biomedical engineering
• Mechanical engineering

Background:

• Flexible polyurethane heart valves are crucial for aortic valve replacement.
• Accurate simulation of their dynamic motion and stress is essential for design optimization.
• Existing models may lack efficiency or interactivity for design exploration.

Purpose of the Study:

• To develop and present a numerical model for simulating the coupled motion of flexible heart valves in the aortic position.
• To enable efficient and near real-time simulations for interactive design studies.
• To compute bending stress on the valve during simulated function.

Main Methods:

• Coupling a Lagrangian dynamic leaflet model with a panel method flow solver.
• Utilizing the unsteady Bernoulli equation to link pressure fields.
• Incorporating sub-cycling and fast preconditioning for efficient convergence.
• Employing conformal mapping for two distinct flow domain simulations.
• Calculating bending stress using spline and circle equation techniques.

Main Results:

• Achieved efficient convergence and near real-time simulations of flexible heart valve motion.
• Developed a versatile model allowing interactive study of material properties and geometries.
• Successfully computed bending stress on the valve.
• Demonstrated the model's capability within the IRIS Explorer design environment.

Conclusions:

• The presented numerical model effectively simulates flexible polyurethane heart valve dynamics.
• The coupled approach allows for efficient, interactive design and analysis.
• This tool facilitates the study of various valve designs and their mechanical behavior.