Modelling and Dynamic Characteristics for a Non-metal Pressurized Reservoir with Variable Volume

Abstract With the increasing demand to reduce emissions and save energy, hydraulic reservoirs require new architecture to optimize their weight, space, and volume. Conventional open reservoirs are large, heavy, and easily polluted, and threaten the operation of hydraulic systems. A closed reservoir provides the advantages of small volume and light weight, compared to open reservoirs. In this study, a non-metallic pressure reservoir with variable volume is designed and manufactured for closed-circuit hydraulic systems. The reservoir housing is made of rubber, and the Mooney-Rivlin model is chosen based on the rubber strain properties. The FEA simulation for the reservoir is performed using ANSYS Workbench to obtain the structural stiffness. The major contribution is the establishment of mathematical models for this reservoir, including the volume equation changing with height, flow equation, and force balance equation, to explore the output characteristics of this reservoir. Based on these results, simulation models were built to analyze the output characteristics of the reservoir. Moreover, the test rig of a conventional hydraulic system was transformed into a closed-circuit asymmetric hydraulic system for the reservoir, and preliminary verification experiments were conducted on it. The results demonstrate that the designed reservoir can absorb and discharge oil and supercharge pump inlet to benefit system operation. The changes in the volume and pressure with displacements under different volume ratios and frequencies were obtained, which verified the accuracy of the mathematical models. Owing to its lightweight design and small volume, the reservoir can replace conventional open reservoirs, and this lays a foundation for future theoretical research on this reservoir.