Role of wall compliance and cushioning in the fluid-structure interaction study of a high-flow artery

Purpose: Fluid-structure interaction (FSI) techniques have become widely accepted numerical tools for analysing transient flows through compliant channels and tubes. However, FSI remains computationally demanding and requires assumptions about certain parameters that are often difficult to determine, particularly in biomedical applications. This study aimed to demonstrate the importance of key decisions required to conduct FSI simulations. Methods: Appropriate material properties were selected and parameters that define the magnitude of external reactions and cushioning effects (which are usually unknown but can be discovered through reverse engineering were set). Using a simplified model of an elastic straight tube, which represents a high-flow artery, reduced the influence of shape and associated mesh imperfections on the results. Results: Wall deformation, von Mises stress, wall shear stress and the pressure drop along the tube were analysed. Verification with various mesh densities for the compliant wall demonstrated that mesh fidelity significantly affects von Mises stress and computation time on a standard PC but has a negligible effect on wall deformation, wall shear stress and pressure drop. Conclusions: Varying wall stiffness and foundation stiffness affected the resulting compliance and all monitored parameters. Additionally, applying different mass and stiffness coefficients to define Rayleigh damping identified a safe range of applicability of this type of damping, however, experimental validation is necessary to determine appropriate values for specific applications and avoid overdamping. Finally, the results were discussed in the context of other FSI research and relevant in vivo and in vitro blood flow studies.