Fluid-structure interaction in a free end textile vascular prosthesis

Textile cardiovascular prostheses are tubular structures made of polyester filaments. They present particular mechanical properties linked to wavy form of their walls allowing them to stretch under pressure. Pulsatile blood flow was studied in a moving walls vascular prosthesis. First, an image processing device was used to measure prosthesis displacement under air pressure in an free end impregnated textile prosthesis. Then, fluid-structure interaction is simulated with a numerical computation code allowing to couple prosthesis walls motion with blood flow. Navier-Stokes equations governing fluid flow are numerically solved with N3S code based on finite elements method. The numerical process is based on the Arbitrary Lagrangian Eulerian (ALE) formulation allowing moving domains. The obtained results showed a particular distribution of blood flow velocities and shear stress near the graft walls. The flow velocity distribution near a prosthetic surface is strongly influenced by the crimping morphology and deformation. A local flow analysis is imperative to understanding pathologies implying hemodynamic factors and to optimize the prosthesis design.