The Research On The Radiated Noise Of Actiated Shell By Airborne Noise In The Compartment

The acoustic stealth performance is more important for submarine, because the noise of submarine could be destroyed the acoustic stealth. The research about this field was developed early in our country, and the radiated noise which activated by the vibration of pipeline and bolster from machines in the inner compartment of submarine was studied deeply. But the research on the radiated noise activated by airborne noise of compartment was more laggard then the other aspects, so this Dissertation emphasized on the laws of the radiated noise causing by airborne noise.First, the research development about the characteristics of radiated noise transferring from the airborne noise was introduced. Then, the four kinds of methods used to calculate the transmission loss of sound isolated structure were summarized, such as Wave Analysis, Mode Analysis, Statistics Energy Analysis and Numerical Methods. In the same time, the testing methods were introduced relatively.The model of the field of airborne noise in compartment was build, and the acoustic field can be regarded as a semi-reverberation acoustic field based on the model. The semi-reverberation acoustic field was constituted by two components cumulated, which the directed component is determined by radiated sound in the non-limited space under ideal condition and the reflected component is determined by multiple reflections from trunk bulkhead and equipments installing in the compartment. Based on the semi-reverberation acoustic field, the formula calculating the noise source of airborne noise level was established nearby the compression resistance shell of compartment.The Wave Analysis Approach and Mode Analysis Approach were employed in the theoretical calculation of shell sound radiation activated by airborne noise through considering the advantage and disadvantage of calculation methods of transmission loss for numerous insulated structures. The underwater promulgating rules of radiated noise activated by airborne noise in the compartment were discussed, and transfer function of radiated noise of submarine compartment models were calculated in different thickness.According to the theory, the experiment of radiated noise activated by airborne noise in compartment was taken on and obtained the airborne noises generated by mechanical equipments, the noise signals was used in the mode of loudspeaker. Thus, the information of underwater radiated noise activated by airborne noise in compartment acquired. Furthermore the underwater radiated noise was studied and verified by means of acquired information.