Sensitivity computational-fluid-dynamics analysis on the damping performance of a hydro-pneumatic spring damper system

As the key component in the regular operation of vehicles, the hydro-pneumatic spring damper system is utilized to mitigate body vibration induced by external random excitation. However, precise numerical modeling of this system has remained insufficient. Consequently, a high-fidelity computational fluid dynamics model was developed in this research, which was validated against data obtained from the test rig established for suspension damping devices. Furthermore, the effects of four individual variables on the rigidity and damping characteristics of the system were systematically investigated in this study. The coupling effects of throttle hole diameter and excitation frequency on damping characteristics have been analyzed based on the result of univariate analysis combined with surrogate model and the sensitivity analysis method. The study highlights the significant role of nonlinear dynamic behavior in shaping the vibration attenuation performance of hydro-pneumatic spring damper system, especially under large excitation amplitudes where nonlinear stiffness, flow resistance, and fluid–structure interactions become dominant. This research presents a novel perspective on the damping characteristics of the system and provides a solid theoretical basis for damping regulation and design variables of hydro-pneumatic spring damper system.