Hysteresis of Suspension Shock Absorbers: Modeling and Effects on Vehicle Dynamic Performance

Hysteresis is widely observed in vehicle suspension shock absorbers and can significantly influence vehicle dynamic responses. Although various hysteresis models have been developed to reproduce experimentally observed force–velocity loops, the effects of damper hysteresis on the overall dynamic performance of passive and semi-active suspension systems remain insufficiently quantified. In this study, a parameterized physics-based damper model is developed by incorporating hydraulic-oil compressibility and pressure-dependent gas dissolution and release. The model is experimentally validated using the force–velocity characteristics of a commercial twin-tube hydraulic shock absorber and is subsequently integrated into passive and semi-active suspension systems. Suspension performance is evaluated under bump and random road excitations in terms of settling time, body acceleration (BA), suspension working space (SWS), and dynamic tire deflection (DTD). The results show that the influence of damper hysteresis depends on both the excitation condition and the suspension configuration. Under bump-road excitation, hysteresis reduces the peak BA and DTD while increasing the peak SWS for both passive and semi-active suspensions, and it shortens the corresponding settling times. The variations are more pronounced in the semi-active suspension. Under random road excitation, hysteresis increases the RMS values of BA and DTD by 6.10% and 4.70%, respectively, for the passive suspension, and by 11.09% and 6.86%, respectively, for the semi-active suspension employing skyhook control. The RMS value of SWS also increases, although its variation is comparatively smaller. These results demonstrate that damper hysteresis produces excitation- and response-dependent effects rather than a uniformly detrimental influence on suspension performance. The proposed modeling framework provides a physically interpretable basis for high-fidelity suspension simulation and for the design and evaluation of suspension control strategies considering damper hysteresis.