Research on natural vibration characteristic of metal pipelines with different length

For the vibration of the aero pipeline and the conveying pipeline exists universally and the vibration has effects on the pipeline life, the detection accuracy and the system stability, the research on the natural characteristic of the pipeline vibration has promising prospects. In this paper, the vibration mathematical model is built with the simple and practical Rayleigh-Ritz energy method to calculate the natural frequency and the mode of vibration theoretically. In addition, the finite element simulation model is built in the ADINA software to obtain the simulation results of the natural frequency. Moreover, the experiment is conducted through hitting the pipeline with the force hammer and the three directions acceleration detected by the three-axis acceleration sensor are obtained with the NI compact RIO acquisition equipment. The experiment data is processed with the Fast Fourier transform and power spectral density method involved with wavelet de-noising to get the tested natural frequency, which indicates that the theoretical analysis results are close to the experimental results. The researches above show that the Rayleigh-Ritz energy method is a simple, rapid and practical method to calculate the theoretically natural frequency of the pipeline vibration and the simulation model in ADINA can be used for vibration characteristic analysis with some proper boundaries conditions, which will provide the foundation for the vibration reduction theory research and the engineering application.