Influence of geometric simplifications on stresses and strains in aneurysm model

Abstract

The paper deals with a possibility of replacing real cross sections of abdominal aortic aneurysm (AAA) by simplified cross sections with a circular or elliptic shape and with the influence of these simplifications on results obtained by FEM solutions. The shapes of AAA cross sections are obtained from sequenced CT frames of a real patient. Naturally, the assumption of simplified cross section shapes smoothes down many local shape variations. To assess the influence of this effect on the calculated stress-strain states, a comparison of two models has been carried out. First, the analysis was realized with an real geometry model, created from the original, unchanged CT frames of the AAA. Second, a geometric model was created from the simplified CT frames with circular or elliptical shape of the cross sections. The same FE stress-strain analysis was carried out in both cases with a hyperelast-ic constitutive model. Comparison of results is then made via maximal principal stresses and strains in the AAA wall.