A COMPUTATIONAL STUDY ON AXISYMMETRIC ABDOMINAL AORTIC ANEURYSM MODELS USING FLUID-STRUCTURE INTERACTIONS UNDER PULSATILE FLOW CONDITIONS

Fluid-structure interaction study was performed on various abdominal aortic aneurysm (AAA) models under the pulsatile flow condition. Eight aneurysm models were made with four different dilatation sizes and two different wall thickness. Von Mises stress increased at the proximal and distal region (+/- 1D) of the aneurysm as well as the maximum dilatation, where both change in diameter and radial movement were larger than any other site with more dilated models. In spite of considerable radial movements, axial movements of the aneurysm wall were dominant and were larger in the proximal region of the aneurysm than in the distal region of the aneurysm. Wall shear rate, in general, increased further for uniform wall thickness models and for less dilated models, which means that wall shear rate is closely related to the motion of the wall. We con firmed the phase delay between the pressure gradient and wall shear rate. Throughout the entire pulsatile cycle, a weak recirculating vortex near the proximal end moved further distally in the aneurysm with increase in size and strength. Larger and stronger vortex was dominant inside the aneurysm with more dilated models and decelerating pressure gradient had a relatively stronger effect on the flow.