Abstract:
In cardiovascular field angioplasty plays an important role. It is widening of a blocked vessel
by balloon catheter. Stent holds an important role in angioplasty. A stent is any medical device
that supports tissue, but most commonly a stent refers to a specific medical device that is placed
inside an artery after angiography to stop the artery from becoming blocked again. An arterial
stent is a mesh like tube often made of metal/fiber that can expand through balloon expansion
once it is inserted into an artery.
The most common problems related to stents are improper expansion and restenosis inside
the vessel. The balloon transfers the pressure as load to expand the stent. Restenosis is the
narrowing of artery/blood vessel. This narrowing of vessel is due to the fact that stent strength
decreases with time and mechanical load is passed to the surrounding tissue.
This work presents the study carried out using carbon fiber composite poly-lactic acid as
basic material for stent. The type of stent used was coiled. Stent expansion procedure was
simulated using non-linear FEM model in Ansys, which is considered to be the best possible way
to simulate expansion procedure for current design of stents.
Interaction between balloon material and stent surface was modeled as frictional contact. The
results of stent were analyzed with respect to stress, strain and deflection which mainly
contribute to cause of restenosis.
Two cases (i) Double-end constrained and (ii) single-end constrained were simulated with
different boundary conditions of balloon expansion. Radial recoil, longitudinal recoil and axial
displacement results were analyzed.
