A refined stiffness model of rolling lobe air spring with structural parameters and the stiffness characteristics of rubber bellows

Abstract An accurate model of rolling lobe air spring (RLAS) is the key to achieve the design, matching and optimization of air suspension. A refined stiffness model of RLAS with structural parameters and the stiffness characteristics of rubber bellows is developed in this paper. Prediction models of structural parameters, including effective area and its change rate, effective volume and its change rate, are obtained by geometrical and mechanical analysis. A nonlinear hysteresis model of rubber bellows is also proposed, which is composed of a fractional Kelvin-Voigt model and a smooth friction model in parallel. The structural parameters were identified by the experiments, including static stiffness and dynamic stiffness tests using the MTS370. The conclusions suggest that amplitude dependency and frequency dependency of RLAS can be completely characterized by the refined stiffness model. The refined stiffness model provides theoretical support for mechanical property match of RLAS.