Due to the stricter roles of the government and the higher requirement of a comfortable automobile, the NVH (Noise Vibration and Harshness) performance of vehicles has become one of the most important traits at the automobile market. Considering the cost, it is more economical and practical to improve the NVH performance by using the vibration-isolating or noise-reducing materials. Vibration damping alloy as one of the new material has a promising prospect due to its great damping characteristics.
In this paper, the vibration-isolating and noise-reducing performances of the vibration damping alloy have been experimentally investigated in a semi-anechoic room. Frequency response function test has been carried with the test rod made of vibration damping alloy and 45 steel to calculate the damping ratio of the two materials based on the half-power bandwidth method. The radiation noise characteristics of the two test rods under different excitation forces have also been evaluated.
Conclusions drawn from the experiment suggested that the damping ratio of 45 steel rod were 0.0125 in vertical axial direction and 0.0165 in axial direction. While, the damping ratio of vibration damping alloy rod were 0.0236 in vertical axial direction and 0.0234 in axial direction, 89% and 42% higher than the 45 steel sample, respectively. With the increase of the exciting force, the radiation noise increased for both two materials, and the radiation noise level of the vibration damping alloy rod was much lower than 45 steel rod. And the difference between these two materials remained unchanged with the increase of exciting force. In addition, the duration of noise attenuation for vibration damping alloy rod was much shorter than the 45 steel.