Poppet valve is one of the most popular components in hydraulics, and it is also known as a trouble maker because it induces some unpredictable vibration in hydraulic system. In this research, thanks to the rapid development of visualization technology and digital simulation technology, we make a re-study on the well-known problem of unpredictable vibration phenomenon. Results show that; 1) stability of a poppet valve essentially depends on the components and parameters of the system, but the stability characteristics are influenced by the cavitation state at the downstream of the valve, 2) by changes in the compressibility of the hydraulic fluid with cavitation, frequency characteristics of the poppet valve are changed to unstable ones. Since the cavitation has complicated relations with various factors, the prediction of vibration of the poppet valve affected by cavitation is generally difficult. Therefore, the vibration may come out suddenly beyond prediction. The results of this paper can give a guide for the cavitation vibration of a poppet valve.
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