Simulation And Analysis Of Vehicle Ride Comfort Affected By Suspension Rubber Bushing

With the development of automobile industry, people’s demand for cars in energy conservation, environmental protection, comfort and reliability has been higher and higher.In the guiding device of the suspension system(such as arm and rear axle), more and more rubber bushings are used to connect with the body. In the premise of hardly change at low frequency vibration isolation characteristics, rubber bushing can greatly improve suspension system in the effect of high frequency vibration isolation, helping the suspension system to isolate the high frequency natural vibration and reduce vehicle noise caused by road roughness, and having the advantages of elastic characteristics and attenuation characteristics. Rubber bushing has become an important component of the vehicle indispensable.Taking a car for the study, in order to improve the stability of vehicle ride comfort and handling, the rubber bushing parameters are optimized. The main research works are as follows:Firstly, several common super-elastic constitutive models are introduced, according to the test data of a uniaxial tensile materials, calculated the equation coefficients for each of the constitutive model with using the nonlinear least squares method, fit suspension rubber bushing material stress- strain relations curve and compared with the experimental curve,select the most suitable rubber material super-elastic constitutive model; using finite element simulation to get the stiffness curve in the rest each direction of the rubber bushing, the dynamic properties of the rubber bushing with the excitation frequency and amplitude changes were discussed according to the experimental data.Secondly, with the comparison and analysis mathematical model of three rubber bushings which are now widely used, propose a precision rubber bushings model with a superposition of elastic force unit, sticky elastic unit and friction unit. According to the test data, rubber bushing model parameter are identified. The model can reflect excitation frequency and excitation amplitude impact on mechanical properties of the rubber bushing,which is closer to the true situation.Then, with the ADAMS software GFOSUB user subroutine, the precision rubber bushing model is imported in suspension model. Establish a multibody dynamics model with consideration of nonlinear rubber bushing McPherson suspension rigid-flexible coupling, compare the K&C characteristics of the suspension system with consideration the nonlinear rubber bushing and without consideration rubber bushing, and establish multi-body dynamics model of the vehicle, simulate its ride comfort and handling stability.Finally, on the basis of multi-body dynamics model of the vehicle, to optimize the vehicle roll angle with taking into account the simulation of chassis vertical acceleration rms and steering wheel, choose an appropriate multi-objective optimization algorithm,optimize the parameters of the rubber bushing to improve vehicle ride comfort and handling stability.