Study on Method of Vibration Analysis for Ship Design : 2nd Report : Vibration Analysis by Database Method

Abstract

Vibration analysis methods which are applied to present ship design can be usually calssified into four groups, those are empirical formulas, methods by simple analytical models, 3 Dimensional Finite Element Method and Database method. In the advanced vibration design method which was proposed in the first report, Database method plays an important role. In the second report, we describe Database method and its application and discuss vibration analysis by Database method, especially concerning to validity. An example of build-up of actual Database for ship vibration was introduced. Standard error of trendlines derived from reggesion analysis and acuracy of estimated natural frequency were investigated for different selection of data group and vibration variable. By choosing proper combination of data group and vibration variable, 2-node vertical natural frequency by Database method was found to show within 5 percent accuracy that is comparable to that by 3d Finite Element Method.