Three-terminal configuration optimisation for enhancing hydraulic shock absorber performance with graph theory

Hydraulic shock absorbers in passenger vehicles typically generate damping through valves and orifices that create a restricted fluid passage between the cylinder’s upper and lower chambers. Motivated by the proven effectiveness of inerters in various applications, this study investigates the integration of hydraulic inertance into this fluid passage to enhance absorber performance. While prior research has explored such integration, a systematic method for identifying optimal configurations of hydraulic stiffness, damping, and inertance elements within the passage remains undeveloped. To address this gap, this study proposes a novel configuration-optimisation framework for hydraulic absorbers using a pre-defined number of each element type. The absorber is modelled as a three-terminal hydraulic network, and a graph-based enumeration method is introduced to generate all feasible network layouts. Each candidate is then tuned and evaluated to determine the optimal design, which is subsequently realised using physical components considering necessary nonlinear and parasitic effects. A numerical case study involving a simplified car model demonstrates the framework’s effectiveness. The tradeoff between ride comfort and road handling ability is investigated. For a comfort-oriented design scenario, using just one stiffness, one damping, and one inertance element, the proposed method identifies a physical design that improves ride comfort by 19.4% compared with a conventional absorber with a single orifice in the fluid passage.