A FINITE ELEMENT ANALYSIS OF THE PERFORMANCE OF STENTS FOR ANGIOPLASTY USING THE HYDROFORMING PROCESS Tobias Anderson Guimarães, Rogério de Araújo, Arthur Machado Langoni e Sônia Aparecida Goulart de Oliveira
Resumo: Nowadays, the implant process of stents for angioplasty is the procedure most used for the treatment of the restenosis of the coronary arteries. In order to prevent the restenosis, a stent should absorb a large amount of plastic strain energy during its expansion to avoid the re-closure of artery wall after the implant. According to this design criterion, it was applied the topological optimization technique to provide the best layout of a unit or cell to be used in the formation of the tubular structure of a stent. Subsequently, the topologically optimized stent cell was employed to create the three dimensional stent structure using the software Autocad/Mechanical Desktop® for the generation and treatment of this model. From this model, it was applied the software Stampack® of explicit finite elements for the simulation and analysis of the expansion process of optimized stent during the angioplasty balloon by hydroforming. Although the hydroforming has been extensively employed in forming process of tubes to be used in the automotive industry, it was used in this work for the study of mechanical behavior of stents during the angioplasty. From the simulation by finite elements, it was possible to predict some design parameters of this novel optimized stent model, such as, the pressure of expansion to be applied in the balloon and the plastic strain field of the stent structure after the implant.
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