Research On The Influence Of Rigid-flexible Coupling Nonlinear Rear Independent Suspension On Vehicle Performance

Suspension system,as an important assembly of the car,transmits the force and moment,attenuates the road excitation,and affects the maneuverability and ride comfort of the vehicle.The traditional linear multi-rigid model has improved the structure,performance and control technology of suspension system.However,with the development of the vehicle towards higher speed and lighter weight,the influence of nonlinear factors and flexible components on the dynamic performance of automotive can not be ignored.Based on a suspension assembly development and design project,this article is to study the impact of rigid-flexible coupling nonlinearity on vehicle performance,which is important for suspension structure optimization and vehicle performance improvement.Firstly,the main non-linear factors of the suspension system are the coil spring,the shock absorber and the rubber bushing according to its characteristics and the basic characteristics of structural nonlinearity.The mathematical models of the coil spring and the shock absorber are established respectively with the idea of discretization and the matching between shock absorber parameters and suspension damping,and the theoretical model of coil spring is verified by the finite element simulation results.At the same time,the mathematical model of the rubber bushing is established by combining the theory with the test.The parameters in the model are identified with the test data and the reconstructed model was in good agreement with the test results,which verifies the accuracy of the model.Secondly,a 1/4 vehicle dynamics model was established to analyze the vibration characteristics of the system and it was found that the nonlinear suspension has an inhibitory effect on vehicle vibration.In order to analyze the vibration of the system more comprehensively,an 11-DOF vehicle model was established.The results show that the car runs smoothly on the Class B road surface.At the same time,compared with the suspension stroke,the body centroid acceleration and the wheel dynamic load of the nonlinear suspension at different speeds.The results verify the inhibitory effect of nonlinear factors on vehicle vibration,and the change trends of the evaluation indexes in the two models are basically the same.The amplitude is within the acceptable range of the human body,which shows the rationality of the model.Finally,the rear independent suspension virtual prototype model built by Adams is simulated under the same conditions,and analyzed the influence of the nonlinear characteristics of the suspension on the K&C characteristic parameters.The results show that the nonlinear factors have no obvious effect on the K-characteristics of the suspension,and have a greater influence on the C-characteristics.The wheelset is the most affected,the rate of change is as high as 71.8%,followed by the toe-in and camber angles.46.2% and 27.2%.In addition,considering the flexible deformation of the members in the suspension system,a rigid-flexible coupling nonlinear model of the rear suspension is established in conjunction with ANSYS.Compared with the simulation results of multi-rigid nonlinear models under parallel wheel-hopping,lateral-force and longitudinal-force conditions,and combined with the actual vehicle K&C test data,which verifies the rationality of the rigid-flexible coupled nonlinear model.