Repeated impact failure mechanisms in valve port for water hydraulic high-speed on/off valve: Experimental and numerical analysis

Abstract

Water hydraulic high-speed on/off valves (WHSVs) are critical components in digital water hydraulic systems due to their exceptional responsiveness and sealing performance. However, frequent high-speed impact on the valve port of the WHSV can lead to progressive seal failure, severely compromising system reliability. This study integrates experimental and numerical simulation results to reveal the impact failure mechanisms of the valve port of the WHSV. The changes in the leakage flow and morphology of the valve port under different numbers of impacts are analyzed by experiment. Meanwhile, an explicit dynamic finite element method is employed to simulate the stress and deformation behavior of the valve seat during impacts, which utilizes precise initial impact parameters derived from an accurate mathematical model of the WHSV, ensuring the reliability and accuracy of the simulation analysis. The experimental results show a significant increase in the leakage of the valve port with the number of impacts. Simulation results indicate that the equivalent plastic strain of the valve port increases with the number of impacts but ultimately tends to saturate. The inner chamfer sharp edge of the valve port is identified as the critical region for stress concentration and plastic deformation, as predicted by simulations and confirmed by experimental observations of fatigue-induced cracks and gaps. Comprehensive analysis results reveal that the root cause of the impact failure of the valve port lies in localized plastic deformation, enlarging the sealing contact area and thus reducing the sealing pressure. Moreover, cracks and gaps near the inner chamfer sharp edge increase the flow area of the valve port and aggravate leakage.