Fluid-structure Interaction Analysis Of Pulsatile Flow Within A Layered And Stenotic Aorta

By introducing the in-vivo pulsatile waveforms and considering the fully fluid-structure interaction (FSI) between the layered elastic aorta walls and the blood flow, the influence of the localized stenosis and media anisotropy on the blood flow and stress distribution in the aorta walls is discussed. The main results are as follows:(1) The hemodynamic characteristics, such as velocity and pressure, are abnormal in the stenotic aorta. The whirlpool forms at the obstructed and downstream unobstructed regions.(2) The maximum wall shear stress appears at the throat of the stenosis. Downstream region appears low and oscillated shear stresses. In addition, along with the increase of the stenotic ratio, the amplitude of the maximum shear stress will be intensively increased and localized, and the sensitivity is also increased. In the aorta with unsymmetrical stenosis, the Von Mises stresses reach the peak value at the side with the surface protuberance, but they are reduced at the side with no protuberance. The sign variation of the layer interface shear stresses near the throat indicates the variation of the shear direction which increases the opportunity of shear damage at the transition plane. The unsymmetrical stenosis causes higher stresses at the side with the surface protuberance than symmetrical one, but lower at the side with no protuberance.(3) The elastic modulus strengthening in the radial direction has great influence on the stress distribution in aortic walls. Von Mises stress levels, as well as the stress jump at layer interfaces, are increased along with the modulus strengthening in the radial direction. The shear stress state may change along with the sclerosis in the radial direction. Moreover, the shear stress levels at the fluid-solid and intima-media interfaces are higher than that at media-adventitia layer.