FINITE ELEMENT ANALYSIS OF AORTAL BIFURCATION

Abstract

Arterial bifurcations loaded by internal pressure represent significant stress concentrators. Increased mechanical stress inside arterial wall probably accelerates pathogenic processes at these places. Stress concentration factor (SCF) depends mainly on geometry, loading and material. This work presents a map of SCFs calculated by FEM at aortic bifurcation (AB) loaded by static internal pressure. Influence of geometry (aortic diameter, wall thickness, bifurcation angle, "non-planarity" angle and radius of apex), material properties and internal pressure were evaluated statistically by regression of FEM results. Two variants of materials were used (linear Hook and hyper elastic Ogden). Viscoelastic behaviour, anisotropy and prestrain were neglected. Results indicate that the highest Mises stress appears in the inner side of AB apex and that the SCF is negatively correlated with bifurcation angle and with internal pressure. The SCF varies from 4,5 to 7,5 (Hook) and from 7 to 21 (Ogden).