The viscosity of the fluids inside a viscous damper is essential for the energy absorption and dissipation capabilities of the damper. However, service-induced changes in viscosity can significantly reduce the seismic performance of viscous dampers over time. Hence, it is necessary to develop an effective approach to monitor the viscosity of fluids in dampers. In this paper, an active sensing method to monitor the viscosity of fluids with piezoceramic transducers is proposed. Two transducers are installed inside a damper to separately function as an actuator and a sensor to respectively emit and receive vibration signals. The relationship between the viscosity of the fluids and the signal amplitude is analyzed from the perspective of the one-dimensional wave theory. A viscosity variation index (VVI) is defined to quantify the relationship between the amplitude of received signals and the fluid viscosity. Numerical results show that the VVI decreases exponentially with the increasing viscosity of the damper’s fluids. The experimental results agree well with the numerical analysis, thus validating the feasibility of the proposed approach.

粘性阻尼器内部的流体粘度对于阻尼器的能量吸收和耗散能力至关重要。但是，服务引起的粘度变化会随着时间的推移显着降低粘性阻尼器的抗震性能。因此，有必要开发一种有效的方法来监测阻尼器中流体的粘度。本文提出了一种利用压电陶瓷换能器监测流体粘度的主动传感方法。两个传感器安装在阻尼器内部，分别用作致动器和传感器，分别发出和接收振动信号。从一维波理论的角度分析了流体的粘度与信号幅度之间的关系。定义粘度变化指数（VVI）以量化接收信号的振幅与流体粘度之间的关系。数值结果表明，VVI随着阻尼器流体粘度的增加呈指数下降。实验结果与数值分析吻合得很好，从而验证了该方法的可行性。