Impact of Preload and Amplitude on the High-Frequency Behavior of Rubber Bushings in Electric Vehicles: An Experimental Study

Electric vehicles (EVs) are particularly susceptible to high-frequency noise, with rubber eigenmodes significantly influencing these noise characteristics. Unlike internal combustion engine (ICE) vehicles, EVs experience pronounced variations in dynamic preload during torque rise, which are substantially higher. This dynamic preload variation can markedly impact the high-frequency behaviour of preloaded rubber bushings in their installed state. This study investigates the effects of preload and amplitude on the high-frequency dynamic performance of rubber bushings specifically designed for EV applications. These bushings are crucial for vibration isolation and noise reduction, with their role in noise, vibration, and harshness (NVH) management being more critical in EVs due to the absence of traditional engine noise. The experimental investigation examines how preload and excitation amplitude variations influence the dynamic stiffness, damping properties, and overall performance of rubber bushings under high-frequency excitation. The research methodology involves subjecting rubber bushings to various preload conditions and excitation amplitudes across relevant high-frequency domains. The findings reveal significant dependencies of dynamic characteristics on preload and amplitude, identifying critical thresholds where performance is notably affected. These insights are pivotal for optimizing rubber bushings in EVs, contributing to improved ride quality, enhanced NVH performance, and increased vehicle durability. Keywords Electric Vehicles (EVs), Rubber Bushings, High-Frequency Noise, Vibration Isolation, Noise, Vibration, and Harshness (NVH).