| As the main vibration isolation element of the automobile,the bushing type rubber vibration isolator is of great significance to reduce the transmission of vehicle vibration and improve its riding comfort.Compared with rubber bushings,hydraulic bushings provide large stiffness and large damping at low frequencies,quickly attenuate vibration,and provide small stiffness and damping at high frequencies,isolating vibration and noise.Therefore,the development and manufacture of hydraulic bushings with good vibration isolation performance has increasingly become the focus of auto parts manufacturers.The rubber main spring and liquid medium are the main parts of hydraulic bushing to generate stiffness and damping,but the nonlinear characteristics of rubber and liquid materials make it difficult to study the vibration isolation mechanism of hydraulic bushing.The hydraulic bushing of the suspension will be subjected to high,low temperature and alternating loads during the driving of the car,and the change of temperature will cause the properties of rubber and liquid materials to change.Therefore,it is very important to study the influence of temperature on the static and dynamic characteristics of the hydraulic bushing.Needed.Based on the hydraulic bushing installed on the lower arm of a vehicle front suspension,this paper uses the fluid-structure coupling finite element method and the lumped parameter method to analyze its static and dynamic characteristics.First,in order to study the specific effect of temperature on the physical properties of rubber materials and oil materials,the experimental curves of rubber materials and oil viscosity-temperature relationship curves at different temperatures were analyzed,and the parameters of the rubber constitutive model and oil at different temperatures were obtained.Physical parameters,which provide necessary material parameters for finite element analysis of hydraulic bushings.Secondly,the 3D model of the hydraulic bushing is established by CATIA software,and the finite element model of the hydraulic bushing is obtained by using the finite element method to discretize the mesh.Based on the hydraulic servo system,a test bench was built and the finite element model was verified.By comparing the test results of the bench with the numerical analysis results,the accuracy of the finite element model was verified.On this basis,the changing law of static and dynamic characteristic curves of hydraulic bushings at different temperatures is studied.The results show that the temperature is inversely proportional to the static stiffness of the hydraulic bushing.The dynamic characteristics at23℃ and 80℃ are not much different,but the dynamic characteristics at-30℃ change significantly.As the frequency increases,the dynamic stiffness tends to increase.,the damping lag angle first increases and then decreases.Then,the lumped parameter model of the hydraulic bush is established by comprehensively using the fluid theory and the mechanics theory,and the main parameters of the model are obtained by the finite element software analysis.By comparing the simulation results of the lumped parameter model dynamic characteristics with the test results at 23℃,the trend of the two is consistent,and the relative error is within a reasonable range.On this basis,the lumped parameter models of-30℃ and 80℃ were established,which provided a reference for the subsequent design of hydraulic bushings.Finally,the control variable method is used to analyze the influence of the relevant parameters of the hydraulic bushing on its dynamic characteristics.The analysis results show that the structural parameters of the inertial channel body have the greatest influence on the dynamic characteristics of the hydraulic bushing,which guides the performance improvement of the hydraulic bushing.The dynamic stiffness of the hydraulic bushing is quadratic design using the lumped parameter model,and the expected dynamic stiffness curve is obtained. |
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