統計能量法於FRP船舶艙間噪音評估之應用

Applications of Statistical Energy Analysis Method to Predict Cabin Noise in a FRP Fastboat

To develop a high performance yacht is the target of what the Taiwan Yacht Builders pursue. One of the main requirements of high performance yacht is the ”comfort”. This means low noise and vibration level. Unlike other structure, however, ship structure is much more complex and is affected by external forces from wave impacts, propulsion system (e.g. main engine, propeller), and auxiliary machines, etc. Besides, there is a variety of combination of fiber sheet, resin, and core material in use to form the major hull and cabin structures in FRP boats. Thus, the prediction of shipboard noise in FPR ship is more difficult than in boat with steel or aluminum structures. The goal of this paper is to predict cabin noise level in a FRP fast boat using Statistical Energy Analysis (SEA) method. First, twelve FRP test specimens were built with different lamination scheme according to their locations on the target boat, and vibration tests were performed to obtain the Damping Loss Factors and Coupling Loss Factors for these FRP laminates. These data were then put into the SEA model to predict the cabin noise under different operating conditions. The results show that the predicted noise levels coincide well with the measured data except at fore cabin under transit conditions. And this validates SEA as a potential tool for the noise prediction for FRP boats. 開發高舒適性之遊艇，為國內遊艇業界追求之目標，而高舒適性之基本要求莫過於較低之振動與噪音。然而船舶振噪源眾多，如：推進系統之主機、輔機、螺槳、及環境之波擊等；再加上遊艇本身為一複雜結構，其主材料FRP更有各式各樣的組合，因此如何正確的評估噪音便成為重要但卻困難的課題。本研究主要內容為統計能量法於FRP船舶艙間噪音評估之應用。步驟上首先擇定一艘FRP快艇，針對船體不同位置之積層組合，製作FRP試體以量測噪音預估時所需要之參數；接著建立該艇之統計能量模型並進行艙間噪音之評估；最後則將計算值與實測值作一驗證。結果顯示，除艏部艙間於行進狀況下誤差較大外，其他艙間之計算值與實測值有不錯的一致性，證實統計能量法應可應用於FRP船舶艙間噪音預估。