Mechanical modeling of self-expandable stent fabricated using braiding technology.
The mechanical behavior of a stent is one of the important factors involved in ensuring its opening within arterial conduits. This study aimed to develop a mechanical model for designing self-expandable stents fabricated using braiding technology. For this purpose, a finite element model was constructed by developing a preprocessing program for the three-dimensional geometrical modeling of the braiding structure inside stents, and validated for various stents with different braiding structures. The constituent wires (Nitinol) in the braided stents were assumed to be superelastic material and their mechanical behavior was incorporated into the finite element software through a user material subroutine (VUMAT in ABAQUS) employing a one-dimensional superelastic model. For the verification of the model, several braided stents were manufactured using an automated braiding machine and characterized focusing on their compressive behavior. It was observed that the braided stents showed a hysteresis between their loading and unloading behavior when a compressive load was applied to the braided tube. Through the finite element analysis, it was concluded that the current mechanical model can appropriately predict the mechanical behavior of braided stents including such hysteretic behavior, and that the hysteresis was caused by the slippage between the constituent wires and their superelastic property.
Kim
Ju Hyun
JH
Intelligent Textile System Research Center, Department of Materials Science and Engineering, Seoul National University, 599 Gwanangno, Gwanak-gu, Seoul 151-742, Republic of Korea.
Kang
Tae Jin
TJ
Yu
Woong-Ryeol
WR
D001807:Blood Vessel Prosthesis; D003198:Computer Simulation; D017076:Computer-Aided Design; D055119:Elastic Modulus; D019544:Equipment Failure Analysis / Q000379:methods*; D019563:Mechanics; D008962:Models, Theoretical; D011474:Prosthesis Design / Q000379:methods*; D015607:Stents; D013314:Stress, Mechanical