Finite-element simulation of stent expansion

A considerable amount of research has been carried out in order to improve the quality and feasibility of stents in recent years. However, published works on simulation of stent expansion using computer software are relatively rare. In this paper, a nonlinear finite-element method was employed to analyse the expansion of a stent using internal pressure. The pressure was applied as a surface load on the inner surface, expanding the stent radially past its elastic limit to a maximum diameter. The total reduction in length as the stent expands radially was also calculated. The analyses were performed using finite-element packages LS-DYNA for solution of the problem and ANSYS (version 5.5) as a pre- and post-processor. Two different load application speeds were investigated in the simulations and the results were compared. This paper concentrates on the effect of the speed of pressure applied on a stent during the expansion process. The issues discussed in this study include the extent of expansion, foreshortening of the stent and the stress levels at different increments of pressure due to the different speeds of application of the pressure.