NONLINEAR DYNAMIC CHARACTERISTICS AND OPTIMAL DESIGN OF VENTILATOR PIPELINE POLYMER COMPOSITE DAMPER UNDER RANDOM EXCITATION

Abstract

For severe patients with new coronavirus pneumonia, the use and stability of the ventilator are important. In this paper, we proposed a new type of shock-absorbing structure that can be used to improve the stability of the ventilator’s gas pipeline, thereby reducing the risk of the gas pipeline falling due to external interference. The film shape memory alloy (SMA) compared with bulk SMA is more suitable for gas pipeline shock absorption due to its large volume ratio and extremely high energy density. In order to optimize the performance of actuator and enhance the utilization rate of SMA, the nonlinear characteristics of Ti-Ni thin film actuator are researched and the effect of SMA film position on the system are investigated. The van der Pol term is introduced to fit the hysteresis loop of shape memory materials. Thus, the nonlinear dynamic response of SMA thin film actuator under stochastic excitation is studied. The numerical and experiment results show that the position of SMA can change the system’s stability, the proposed structure can reduce the system’s vibration to the maximum extent. The results indicate that the new proposed polymer/SMA composite film micro-actuator exhibits high energy dissipation ability, and the utilization rate of smart material is enhanced. Therefore, the new damping structure proposed in this paper is of great significance to the damping of gas pipelines.