Investigation of Cavitation Phenomena in the Hydraulic Shock Absorber Based on FSI FEA Method

A three-dimensional fluid–structure interaction (FSI) finite element analysis (FEA) model of a gas-pressured hydraulic shock absorber is constructed. Kunz cavitation model and synchronous-iterative FSI method are utilized to calculate the dynamic responses of the shock absorber system, and the results are partially verified experimentally. The liquid cavitation phenomenon occurs in the high-speed compression stroke, which leads to a decrease in growth rate of compression damping force, and the maximum damping force deviates from the maximum speed position of the main piston. The maximum value of the opening degree of compression stroke valve plate is obtained after the maximum speed position of the main piston in the compression stroke, which is consistent with the law of changes in damping force. Oil pressure in the extension chamber decreases with the increase of the compression speed of the main piston, the fastest pressure drop of the fluid is located between the compression stroke valve plate and the baffle plate. As the compression speed of the main piston increases, oil pressure in the extension chamber decreases, the fluid cavitation area between the valve plate and the baffle plate increases. At the moment of maximum velocity of the main piston in the compression stroke, the area of oil cavitation is extended, but the oil pressure in the extension chamber remains essentially unchanged.