Multi-objective optimization of tracheal stent with J-shaped load-deformation behavior.

The tracheal stent is one of the treatment modalities for tracheal stenosis. However, the mismatch of mechanical properties between the tracheal stent and the trachea may lead to stent migration. The aim of this study is to design a tracheal stent with J-shaped load-deformation behavior based on a multi-objective optimization method. Four design parameters were selected as optimization variables. The optimization objectives were the loads at 5%, 10%, 15%, and 20% deformation during uniaxial tensile test. The optimal Latin hypercube sampling was used to generate training samples, and Kriging surrogate model was constructed between tracheal stent design parameters and mechanical properties. An optimized stent model was established after obtaining the optimal stent design parameters by NSGA-II algorithm. Additionally, a commercial silicone stent model was established as the control. The results indicate that ligament angles and the width of circular arc connected ligaments play a prominent role in the load-deformation curve of the stent. The radial supporting performance (39.79 MPa vs. 4.63 MPa) and anti-migration properties (16.1 N vs. 13.7 N) of the optimized stent are superior to those of the silicone stent. This work demonstrates that a tracheal stent exhibiting a J-shaped load-deformation behavior was designed, which could reduce stent migration.