DYNAMIC RESPONSE AND FIRST PASSAGE OF SMA TRACHEAL STENT IN COUGH PROCESS

Abstract

The high-order nonlinear terms are applied to express the strain–stress curves of shape memory alloy (SMA) materials, and a new type of SMA model is proposed. Cough process is regarded as a strong stochastic process, and the mechanical model of an SMA tracheal stent in cough process is proposed where the large deformation caused by cough is considered. The system’s natural frequency is obtained, and its dynamic response is analyzed. The analysis and simulation results show that when the intensity of outside excitation increased 3.5 times (from 0.2 to 0.7), the system’s first-passage time was advanced by 19%, which means that the increase of the cough intensity will cause the loss of the stent; the large-amplitude vibration can be eliminated by selecting materials with appropriate parameters, which means the loss of tracheal stent can be avoided even in strong cough. This paper provides a new way to avoid the stent’s loss.