SPECTRAL ANALYSIS OF A TRAWLER STRUCTURAL MEMBERS SUBJECTED TO HIGH SEA WAVES

Abstract

The purpose of this study is to clarify the trawler structural members subjected to random sea wave groups with large waves (hydrodynamic forces) to examine the trawler behavior under the above random loading condition to avoid future damages. By adopting the general complex modal theory, identifying the natural frequencies with corresponding mode shapes, the response of the trawler structure analysis with input from the high sea waves is carried out using a kind of direct spectrum analysis method in frequency domain. With the input of power spectral density function given, the explicit expression of the power spectral density function of the output response can be obtained. By taking Fourier inverse transforms, the integrated expressions of the correlation function and of the spectrum are obtained. The mean square values and variety of statistical values can be obtained conveniently leads to the formulation of a mathematical model of a trawler structure model. The detailed model will be used to identify the fundamental vibration mode shapes and corresponding excitation frequencies which will be used to control the safety of the trawler and the crew, to increase the trawler structure optimization, simulating the increased protection of the Trawler.