Experimental and application research on the damping characteristic of thin-wall box

Based on the theoretical calculation and measurement of damping ratio, the mechanism in reducing vibration and noise of viscous liquid was investigated. Aiming at the equivalent thin-wall box, the modal experiments which included different viscous medium, different liquid mass and double-layer plate with different inner plate's distance were designed, and the corresponding damping ratios were gained. The rules of viscous liquid influence on structural vibration and noise were analyzed, the method which can improve the structural damping characteristic was presented and applied to the design of double-layer oil pan. The experimental results show that the increasement of box's liquid mass and the introduction of double-layer plate and inner plate's oil layer can enhance the damping ratio of system, and reduce the power of acoustic radiation.