Abstract:
A stent is a mesh tube that is used to push against arterial walls with the help of a balloon so that the blockages to the blood flow in the arteries can be removed. Many different stent designs exist on the market today and each one with its own unique geometry and application conditions. This analysis demonstrates the deployment process for an arterial stent modeled in Abaqus using an elastic-plastic analysis.
Methodology:
The physics involved in the simulation are complex and can be summarized as follows:
- Contact between the stent and blood vessel, between the stent and a balloon etc.
- Stent boundary conditions that must be defined as per the service conditions and loading cycles.
- Large expansion deformation.
- The stent material is non-linear and needs to be fully defined for the material and design to be properly validated.
Figure 1: FEA Model of a Stent.
Figure 2: FEA Model of a Stent after Contraction
Results and Discussion:
The deployment process for an arterial stent was modeled in Abaqus using elastic-plastic analysis. High stresses were noted along the bend locations in the design. This bending locations were identified as ‘hot-spots’ and are fatigue-critical locations. The geometrical parameters can be used as optimization variables to generate a design capable of better mitigating the stresses.
Figure 3: Stress Distribution in the Stent after Multiple Loading Steps
References:
- Dassault Systemes, Abaqus theory and reference manuals
- Lewis, G. Materials, fluid dynamics, and solid mechanics aspects of coronary artery stents: A state‐of‐the‐art review, Journal of Biomedical Materials Research, 2008.
- Wufu Ma, Fatigue Analysis of a Coronary Artery Stent, FE-Safe Users Conference, 2011.
- Migliavacca, et al. Mechanical behavior of coronary stents investigated through the finite element method, Journal of Biomechanics, June 2002.