High-Frequency Dynamic Stiffness Measurements of Automotive Elastomers for Electric Vehicles

The increasing adoption of electric vehicles (EVs) has intensified the demand for advanced elastomeric materials capable of meeting stringent noise, vibration and harshness (NVH) requirements. Unlike internal combustion engine (ICE) vehicles, EVs lack traditional powertrain-induced masking noise. In the automotive industry the dynamic stiffness of elastomers for internal combustion engines are determined traditionally using hydraulic test rigs up to test frequencies of max. 1000 Hz. Measurements in excess of these frequencies were not possible and are only carried out using computerized FE or CAE calculation models. Electric drive systems generate distinct tonal noise components in the high-frequency range up to 10 kHz , which are well perceptible even at low sound pressure levels. Consequently, the dynamic stiffness characteristics of elastomers up to 3000 Hz are critical for optimizing NVH performance. This study focuses on the high-frequency dynamic stiffness testing of automotive elastomers using a specialized high-frequency test rig. There are two methods for determining the dynamic stiffness of elastomers in accordance with standard EN ISO 10846-2: the direct method and the indirect method. This paper describes measurements according to the direct method using an electrodynamic shaker with application of static preloads. The objective is to accurately determine the frequency-dependent dynamic stiffness and damping properties of elastomeric components, such as engine mounts, bushings, and isolators, which play a crucial role in mitigating structure-borne noise and vibrations. The results provide valuable insights into the viscoelastic behavior of elastomers under high-frequency excitation up to 3 kHz, allowing for the development of optimized materials and component designs tailored for EV applications. The study highlights the influence of construction and loading conditions on dynamic stiffness, contributing to improved NVH performance in next-generation electric vehicles. The findings serve as a foundation for enhancing elastomer design methodologies, ensuring quieter and more comfortable EV interiors while maintaining durability and performance.