A study on dynamic measurement methods based on vibrating wire sensors

Vibrating wire sensors are widely used in long-term static strain monitoring. However, when dynamic measurements are needed, conventional measuring methods are unsuitable. On the basis of the static measuring method, in this paper we propose a new method of dynamic frequency excitation and measurement based on vibrating wire sensors. In the dynamic frequency excitation method, we adopt intermittent self-adaptive excitation which allows the internal steel in the sensor to vibrate continuously, without attenuation. In turn, this allows us to continuously collect and analyze the sensor signal. We use a dynamic frequency measurement algorithm to subsequently process the data, which interpolates three spectral lines based on a windowed fast Fourier transform. The resonance frequency of the sensor is obtained, which then allows us to dynamically acquire the strain. Through data analysis, the theoretical calculation error of the resonance frequency can be obtained to within 0.015 Hz, and the theoretical sampling rate of dynamic strain measurement can reach to 325 Hz. In addition, through our experiments, the efficiency and the feasibility of our methods are verified.