A Method for Calculating High Frequency Dynamic Characteristics of Rubber Isolators under Different Preloads 2022-01-0307

Because the power unit of electric vehicle has large torque, the rubber mount of electric vehicle is fully compressed under the condition of full throttle acceleration. When designing the mount of electric vehicle, the dynamic-to-static stiffness ratio of mount under the case should be as low as possible to improve the vibration isolation rate of the mount. In this paper, a method for calculating the high frequency dynamic characteristics of rubber isolators under different preloads is presented. Firstly, the dynamic characteristics of rubber specimens under various shear pre-strains were tested. The test results show that the dynamic stiffness of specimen decreases at first and then increases with the increase of shear strain. The viscoelastic parameters of rubber in frequency domain under different pre-strain were identified according to the experimental data. Secondly, a finite element modeling method was proposed. The mount elements were grouped according to the octahedral shear strain of elements under corresponding preload, and the corresponding viscoelastic parameters were input for each group. Based on the modeling method, the dynamic characteristics of a rubber mount were calculated. Finally, the dynamic characteristics of the rubber mount under different preloads, when the load case is full throttle acceleration condition and static design position, were tested. The calculation and test results show that the error between the calculation results and the test results is less than 10%. Therefore, the high-frequency dynamic characteristics of rubber mount under different preload can be well predicted by the method presented in this paper.