ARUP; ISBN: 978-0-9562121-5-3 - CMBBE 2012 - Cardiff University

study and the parameter setting can be found in [9].
The simulation applying ABAQUS explicit solver used a crimping rigid cylinder to
crimp the stent models to the outer diameter of 1.2 mm. After that, an expanding rigid
cylinder was used to expand the stent models into a vessel model to the outer diameter
of 3.0 mm, then the stent recoiled with the interaction of the vessel (Fig. 2). Finally A
subroutine compiled for the biodegradable material model was applied in the corrosion
simulation. With the degradation of the stent, the vessel was expected to recoil until the
stent model lost its scaffolding ability. In order to make an effective comparison
between different stent structures, a time unit (t*) normalized on the longer time for
stent models to lose the scaffolding ability was adopted for the results description.
Fig. 2. Meshes of the 3D model of the Model A, including one stent ring, two rigid
cylinders to crimp and expand the ring respectively, and the arterial vessel.
3.2. Corrosion experiments of two MAS samples
After simulation, two MAS samples based on the two designs said before were
manufactured by laser cutting then followed by electro-polishing (Fig. 3). They have
complete structure with the similar length of about 13 mm. Sample A is composed of 9
rings connected by two links between each other, while Sample B alternative three short
rings and two long rings connected by four links between each other (only short ring
was modeled in the previous simulation).
Fig. 3. Samples A (upper) and B (down) according to the two stent designs
The experiment procedure is as following: both samples were first crimped to the outer
diameter of 1.2 mm using a costumed stent crimping machine. After that, the samples
were expanded using an angioplasty balloon to the outer diameter of 3.0 mm then