Prediction of Noise Propagation on Board a Motor Yacht Using Statistical Energy Analysis (SEA)

Abstract

The purpose of this report is the study of the prediction of noise propagation generated on board a motor yacht (40m) still under the construction at Cerri Cantieri Navali shipyard. This investigation is carried out because of the shipyard’s necessity to collect the information about the dynamic and vibration behavior of the structures of the motor yacht. The structure of the yacht is not a conventional one: it is considerably stiffer than the regular semi-displacement motor yacht of nearly the same size because it is of Ice Class. Prediction of noise propagation is of great importance in luxury ships like motor yachts. It is more or less concerned with the vibration of the structures on the ship. Generally, the more vibration there is, the more is the noise production and propagation. Noise propagation issues are determinant not only for the structural reasons but also when the high standards are expected on comfort and well-being. If the limits established by the standards are not exceeded, the habitability will be good which means no health damage will occur. For this study, the complete motor yacht including hull, decks, structures and insulations are going to be finished. Because it is a perfect condition to perform the predictions, measurements and analyze the comparison of the generated results with the noise criteria from RINA measurements, considering that there is less uncertainties regarding the damping in the vibration analysis and induced errors in the input data. The objective of this study is to know the nature of the Vibroacoustic One software which is applied to perform the SEA analysis, to know the acoustic theory of the structures, to make the prediction of noise in each room throughout the analyzed yacht model, to check whether the estimated sound pressure level of noise satisfy the criteria proposed by RINA and whether the created yacht model can be used to make further investigations on this particular field of study. And the behavior of the glass windows especially around the owner’s cabin such that how they contribute to the sound pressure level according to the variation of particular thickness and the behavior of changes in insulation thickness surrounding the acoustic cavity of interest. Moreover, the transmission loss behavior around the critical coincidence frequency of one of the SEA plate panels which contributes the highest power input to the acoustic cavity of interest will be analyzed. The design of yacht, construction plans and technical information will be provided by the shipyard’s responsible office. On the side of software, the analysis of this study is developed through the application of VA One (Vibroacoustic One) software. The creation of yacht model is done through the marine modeler tab inside the software.