| Summary: | 碩士 === 國立臺灣海洋大學 === 系統工程暨造船學系 === 99 === The study of the thesis is to focused on the discussion of the attenuation effect of the vibro-acoustic sound radiation by means of the anti-vibration coating painted on the surface of steel plates (plane structure) and pipes (cirved structure).
Most anti-vibration paints pertain to the viscoelastic material and possess the characteristics of elasticity and viscosity simultaneously. As the structure subjected to external dynamic loads, the mass and the viscocity of surface painted anti-vibration coatings will be increased to make a decrease of the vibration waves thereof, then the vibrational energy can be absorbed partially by the elasticity, and the other part of vibrational energy will be dissipated during the transmission process.
The key point of the thesis is modeling the vibration and the acoustic radiation in the free damping structure model with the anti-vibration coating which is a kind of damping-mushy compound made of water-soluble man-made resin and filler. Due to the thickness of the anti-vibration coatings that spread on the steel plate and the steel pipe, for 0mm, 1mm, 2mm, 3mm, the measuring-noises and the free frequency drop gradually, especially on the free frequency. Regard to the plated-spread anti-vibration coating, it can be decreased about 2~8 dB; and the circular-spread one can be decreased about 2~6 dB.
Analysis and simulation of the acoustic radiation is to discuss the decreasing-vibration behavior of the anti-vibration coating by ANSYS software, and model the vibro-acoustic sound radiation by SYSNOISE software, then compare the simulations to the measurements, and we can get the consequence as the decrease of the radiation efficiency follows the increase in thickness and damping ratio of anti-vibration coating.
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