Acoustical Field Analysis And Noise Reduction Study Of A Cabin Room On A Ship

The cabin noise on ships is a disadvantageous factor for work and rest of the crew. In recent years, with the improvement of requirement for the comfort of the ship, the cabin noise reduction has received extensive attention. The International Marine Organization requires its contracting parties to implement the new " Code on noise levels on board ships "since July 1st, 2014, which presents a higher request for the study of vibration and noise reduction on the ships' cabins. Based on the new standard, the paper makes a deep study of reducing noise on a ship model's cabin by sound-absorbing methods.Referring to the abundant information, the paper firstly analyzes basic rules of sound propagation in a confined space and methods of reducing noise. Then it builds the analysis model of a cabin model which is used in this paper and calculates the natural frequency by using the finite element simulation tool.Then it proceeds sound absorption performance of two new kinds of sound-absorbing materials The sound-absorbing experiment is done in the reverberation room and impedance tubes, for the size of the materials are different. The result comes out that, the materials show good performance while the frequency is above 1kHz.Subsequently, it designs three experimental conditions using the cabin model. And it uses vibration exciter and electrical machine as sound sources to do sound reduction experiment.Finally, analysis of noise reduction in the cabin model is done and it comes out that, if the excitation source is the vibration exciter, the noise has a 9.2dBA reduce when the first material is installed in a large area; it has a 5.9dBA reduce when the first material is installed in a small area; it has a 11.1dBA reduce when the second material is installed in a large area.If he excitation source is the electrical machine, the noise has a 7.5dBA reduce when the first material is installed in a large area; it has a 4.5dBA reduce when the first material is installed in a small area; it has a 7.2dBA reduce when the second material is installed in a large area.