A nonlinear dynamic model of a monotube shock absorber

A physics-based model for a high pressure monotube shock absorber is proposed by which the nonlinear dynamic behavior of these dampers can be analyzed. The bond graph technique is used to model these shock absorbers accurately over a wide range of stroking frequencies (1 to 20 Hz) and to identify the interaction between mechanical, fluid, and thermodynamic elements. Various phenomena are modelled such as fluid inertia effects, laminar orifice flow, air entrained in the hydraulic fluid, and cavitation. Results indicate the fundamental characteristics of shock absorbers are produced by the interaction of resistive and capacitive elements inherent in these systems.