|
چکیده
|
Shape memory alloy (SMA) stents can be employed to decrease the difficulties of femoral artery (FA) diseases. The present simulation modeled the stent material’s superelasticity based on the Helmholtz free energy (Auricchio theory) and Gibbs free energy (Lagoudas theory). The comparative empirical and Auricchio model was almost relatively regular with the empirical data (94%). Furthermore, the present study used FEM to evaluate the impacts of the material properties of the newly designed SMA stent during the radial loading (crimping) and unloading (releasing) process for application in FA. The results showed that the FA SMA stent with material properties contains Af of 293°K, increasing the Af: Austenite finish temperature from 284 to 293°K increased upper plateau stresses (UPSs) by 46%, radial resistance force (RRF) by 54%, lower plateau stresses (LPSs) by 36%, chronic outward force (COF) by 26%, strain by 16%, martensite fraction (MF) by 6.77%, and the strain transformation by 62.5% with a safety factor of about 2. The best mechanical and clinical performance is observed in the FA SMA stent with material properties containing Af of 293°K with favorable COF, RRF, and high conversion strain associated with the great MF and MH (Mechanical Hysteresis) hoop associated with superelastic performance.
|