Numerical Simulation of Localized Bulging in an Inflated Hyperelastic Tube with Fixed Ends

Abstract

When a hyperelastic tube is inflated, the inflation pressure has a maximum for almost all rubber material models, but has no maximum for commonly used arterial models. It is generally believed that the pressure having a maximum is a necessary condition for localized bulging to occur, and therefore aneurysms cannot be modeled as a mechanical bifurcation phenomenon. However, recent theoretical studies have shown that if the axial stretch is fixed during inflation, localized bulging may still occur even if a pressure maximum does not exist in uniform inflation. In this paper, numerical simulations are conducted to confirm this theoretical prediction. It is also demonstrated that if the axial pre-stretch is not sufficiently large, unloading near the two ends can reduce the axial stress to a value close to zero and Euler-type buckling then occurs.