Study On The Cabin Noise In AHTS About The Prediction And Control

A ship as a combination for working, entertainment and rest, is a moving station to all the sailors. Meanwhile, it is very difficult to be avoid from the ship noise, which not only has bad effects to the sailors’ working and living life, but also keeps the machine out of good running. In one word, ship noise brings huge damage. According to this condition,International Maritime Organization passing several meetings, finally, issued that criteria about the ship noise. In DE56, all attentions are paid to living accommodations, most of these cabins are required to reduce 5dB on the basic of old criteria. According to the situation of the current domestic shipbuilding, it needs much more expenditure to meet the new criteria. We will not improve the situation until we could bring the prediction and research of noise into consideration before shipbuilding.This paper using the computing method for prediction of the ship noise based on the characteristics of AHTS(Anchor handling tug supply vessel), applies VA one--an acoustic software from ESI GROUP to predict the cabins’ acoustic pressure level and research the rules of noise control. The main contents of the paper includes:(1)Introduce the basic principle of sound ship structure and the Statistical Energy Analysis and FE-SEA coupling method, which contain their advantage, disadvantage and limits of the two methods’ usage.(2)Establish geometric model by Hypermesh software and acoustic model by VA-ONE software. Set the parameters which includes Modal density, Internal loss factors, Coupling loss factors by empirical formulas. Then, use the SEA method to predict the acoustic pressure level about the 19 target cabins ranging from 125 HZ to 8000 HZ and the FE-SEA coupling method to predict from 63 HZ to 125 HZ. Compare the influence between the main engines and auxiliary engines to the living cabins. The result verify that the auxiliary engines have more effects on the cabins.(3)After summarizing varieties of treatments to control the vibration and noise,according to the results of prediction, analysis the peculiarity and contribution of the cabin noise, confirming which cabin could not meet the criteria and the most important factor to result in the high acoustic pressure level. Then, select three kinds of cabins exceeding thelimit by different levels such as gym room, sick bay and crew room based on the reasons why the target cabin can not be up to the standard. Use the isolation and damping vibration reduction, sound insulation technology, sound absorption technology and highlighting floating floors to make the cabins up to standard. All the progress will give a certain reference assistance for application of the ship design.