Thermo-mechanical Coupling Dynamics Model of Automotive Suspension Hydraulic Shock Absorber

Abstract:

A theoretical thermo-mechanical coupling dynamical model was established,which consists of road irregularity excitation model,two-degree-of-freedom suspension vibration model,empirical shock absorber damping force model by taking temperature effect into consideration and shock absorber thermodynamic model.The empirical shock absorber damping force model was formed as a nonlinear look-up-table by using the damping force,relative velocity and temperature measured under various sine and stochastic displacement excitation.And the parameters of the shock absorber thermodynamic model were identified based on the shock absorber thermodynamic characteristics test.Using the thermo-mechanical coupling dynamics model,shock absorber's operational temperature was predicted and the influence of factors was also numerically investigated.Results show that the thermo-mechanical coupling effect of shock absorber is obvious when vehicle runs on low-grade pavement with high speed.And the simulation results show that vehicle speed,pavement grade,ambient temperature and air flow rate around shock absorber,unsprung mass,shock absorber tube radiating area have great effect on equilibrium temperature,while sprung mass,suspension stiffness and shock absorber thermal capacity coefficient have little effect on equilibrium temperature.