| Hydraulic bushing can provide large dynamic stiffness and large damping lag angle in the case of low frequency and high amplitude,so as to play the role of vibration reduction and noise reduction,improve the NVH characteristics of automobile,and is widely used in various high-end automobiles.Therefore,it is an important part to study the influence of static and dynamic characteristics of hydraulic bushing on vehicle ride comfort.The influence of hydraulic Bush applied in different position on automobile performance is different.Different structural parameters have different effects on the dynamic stiffness of hydraulic bushing.According to the commonly used models to study the mechanical properties of hydraulic bushing and the structural parameters which have great influence on the dynamic stiffness of hydraulic bushing,the lumped parameter model of hydraulic bushing is established.The experimental data of mechanical properties of hydraulic bushing are obtained by means of MTS uniaxial tensile test bench of China Automotive Technology Research center.The accuracy of the model is verified by fitting the analysis of hydraulic bushing with a large number of data.Finally,through the formula,we can know the law of the dynamic stiffness of the hydraulic bushing changing with the frequency and amplitude.According to this formula,we can calculate the dynamic stiffness needed below.The front Mc Pherson independent suspension,rear torsion beam suspension,body,steering,tire and other subsystems are established by Adams/Car software,and the front Mc Pherson independent suspension and rear torsion beam suspension frame system are set up as assembly model.Based on ride comfort,the K&C characteristic conditions which have great influence on ride comfort are selected,and the front Mc Pherson suspension,rear torsion beam suspension frame and other subsystems are analyzed Finally,the multi-body dynamics simulation model of the whole vehicle is built.With the help of Adams/Ride module,the hydraulic bushing model is established,and the parameters are identified by frequency simulation.The identified hydraulic bushing model is used to replace the bushing model in the original vehicle multi-body dynamics simulation model.The accuracy of the vehicle model is verified by the acceleration values in three directions at the center of mass and the dynamic characteristics of the hydraulic bushing.Finally,by changing the parameters of the hydraulic bushing,the stiffness of the hydraulic bushing is increased to 1.5 times of the original stiffness and reduced to 0.5 times of the original stiffness,and the parameters are identified again by Adams/Ride module.The simulation results show that the dynamic characteristics of the hydraulic bushing at the front suspension control arm have a great influence on the vehicle longitudinal vibration,and the smaller the dynamic stiffness is,the smaller the influence on the vehicle ride comfort is,and vice versa.The multi-body dynamic simulation model of the whole vehicle with the mechanical characteristics of the hydraulic bushing built in this thesis can provide accurate theoretical basis for the early development of the whole vehicle chassis and reduce the research and development cycle. |
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