Modeling and analysis of dynamic characteristics of rubber isolators for electric vehicles under high-frequency excitation

Abstract

The rubber isolator is a key component connecting the vehicle body and the powertrain, which plays a significant role in reducing the vibration transmission from the engine to the vehicle body. With the development of electric vehicles, the excitation frequency generated by the powertrain can exceed 2 kHz. The conventional dynamic models are usually used to simulate the low-frequency dynamic characteristics of rubber isolators, in the range of 0–200 Hz, which is the main excitation frequency range of the traditional internal combustion engine vehicle. However, they cannot simulate the high-frequency dynamic characteristics accurately since the inertial force caused by the mass of rubber isolators increases greatly under high frequencies. And the high-frequency dynamic characteristics of rubber isolators is of great significance for isolator fatigue life prediction, powertrain system vibration isolation design and noise control caused by the high-frequency resonance of the isolator. In this paper, a general model with mass elements is proposed to describe the effect of the inertial force on high-frequency dynamic stiffness. Based on the proposed model and considering the different expressions of the viscoelastic properties of rubber isolators, three improved dynamic models of rubber isolators are established, and used to analyze the high-frequency dynamic characteristics of rubber isolators. It has been demonstrated that the inertial force plays a non-negligible role in the dynamic characteristics of rubber isolators under high-frequency excitation. The proposed model can be used to analyze the effect of the inertial force on the dynamic characteristics at high frequencies accurately. The high-frequency dynamic characteristic modeling method of rubber isolators presented in this paper is helpful to the vibration and noise analysis of electric vehicle powertrain systems under high-frequency excitation.