Calculation And Experimental Research On High Frequency Dynamic Stiffness Of Rubber Mount

With the vigorous development of the world automobile industry,more and more rubber materials are applied to the automobile industry.Rubber material is a kind of very good shock absorption material,and rubber mount is one of the important vibration isolation components for automobiles.The dynamic stiffness of the rubber mount affects the NVH performance of the car,and it has a greater impact on the ride comfort and handling stability.With the deepening of research on electric vehicles,the research on high-frequency dynamic stiffness of rubber mounts has become more and more urgent.However,the current research on high-frequency dynamic stiffness of rubber mounts is still not deep enough.In order to guide the development and design of rubber mounts,this paper has carried out the following research work:(1)Identification of rubber material constitutive model parameters.Perform simple tension,biaxial extension,and planar tension tests on rubber materials with different strain levels,to obtain experimental data for hyperelastic parameter identification.Design rubber material specimen test tool and perform simple harmonic dynamic shear test to obtain rubber material dynamic stiffness and hysteresis angle data,determine hyper-elastic-generalized Maxwell model to characterize the dynamic characteristic model of rubber material,and give viscoelastic parameters identification formula,combined with dynamic stiffness and hysteresis angle data to identify the viscoelastic parameters of rubber materials.(2)Calculation and verification of high frequency dynamic stiffness of rubber mount.The drive point dynamic characteristics and cross point dynamic characteristics of the rubber mount are theoretically analyzed,and the high frequency dynamic stiffness test method of the rubber mount is determined to be the cross point dynamic characteristic test method.The rubber mount test tool was designed and experimental tests were carried out.The high frequency dynamic stiffness data of rubber mount with different preloads,acceleration amplitude excitation,rubber hardness,and rubber types were obtained.Developed a rubber mount high-frequency dynamic stiffness simulation analysis process,compared the simulation analysis results with the experimental test results of different preloads,and controlled their relative errors within 15%,indicating that the rubber mount high-frequency dynamic stiffness simulation analysis process is effective and the parameter identification is accurate.(3)Study the influence of the structure of the rubber mount on its high-frequency dynamic stiffness.The research objects are the addition of "rubber flaps" on the outside of the mount and "secondary vibration isolation rubber mount".Taking a rubber mount as the research object,the installation direction and installation position of the rubber mount flaps are simulated and analyzed,and the design method of the rubber mount flaps is summarized,and its feasibility is verified through experiments.Then,taking a tie rod as the research object,finite element analysis was performed on the large bushing,small bushing and tie rod respectively,showing that the secondary vibration isolation has a better vibration damping effect at high frequencies.Afterwards,the influencing factors of the additional mass material and preload are analyzed for the secondary vibration isolation.