Research on the dynamic characteristic of semi-active hydraulic damping strut

Abstract

To reduce the vibration and shock of powertrain in the process of engine key on/off and vehicle in situ shift, a novel semi-active hydraulic damping strut is developed. The purpose of this paper is to study and discuss the dynamic stiffness model of the semi-active hydraulic damping strut. In this study, the dynamic characteristics of semi-active hydraulic damping strut were analyzed based on MTS 831 test rig first. Then, the dynamic stiffness model of semi-active hydraulic damping strut was established based on 2 degrees of freedom vibration system. In this research, a linear, fractional derivative and friction model was used to represent the nonlinear rubber bushing characteristic; the Maxwell model was used to describe the semi-active hydraulic damping strut body model; and the parameters of rubber bushing and semi-active hydraulic damping strut body were identified. The dynamic stiffness values were calculated with solenoid valve energized and not energized at amplitudes of 1 mm and 4 mm, which were consistent with experimental results in low-frequency range. Furthermore, the simplified dynamic stiffness model of the semi-active hydraulic damping strut was discussed, which showed that bushing can be ignored in low-frequency range. Then, the influence of equivalent spring stiffness, damping constant, and rubber bushing stiffness on the stiffness and damping capacity of the semi-active hydraulic damping strut were analyzed. Finally, the prototype of the semi-active hydraulic damping strut was developed and designed based on the vehicle in situ shift and engine key on/off situations, and experiments of the vehicle with and without semi-active hydraulic damping strut were carried out to verify its function.

Effect of semi-active HDS on vehicle longitudinal vibration and shock in the process of in-situ shift with different shift time

“…The dynamic stiffness and damping coefficient of the semi-active HDS with different amplitude and frequency are tested with MTS 831, as shown in Figures 4 and 5. 22 It can be seen that the larger damping can be obtained in low frequency band to reduce the shock and vibration when vehicle is in the process of in-situ shift.…”

Research on dynamic stiffness with the high-order fractional derivative model for rubber bushing

“…At present, the insufficient accuracy of the bushing model is the main reason for the low dynamic simulation accuracy of vehicle and subsystem models. [1][2] Therefore, it is of great significance to establish an accurate model to describe the dynamic characteristics of rubber bushings.…”