The Structural Responses and Local Stress Analysis of a SWATH Ship in Waves

• Main Authors: Ming Ying, Lu, 盧明瑛
• Other Authors: Joe Ming, Yang
• Format: Others
• Language: zh-TW
• Published: 1994
• Online Access: http://ndltd.ncl.edu.tw/handle/19118679198031986223

碩士 === 國立成功大學 === 造船工程學系 === 82 === The purpose of this study is to investigate the static and dynamic structuralresponses of the small-waterplane-area twin- hull(SWATH)ship under harmonic wave excitation.The study is carried out by means of finite element analysis,in which the program "MSC/NASTRAN" and the pre-post processor "MSC/XL" are used. In the static analysis,three kinds of loading conditions, 1.still water condition;2.head seas condition;3.beam seas condition are considered.In order to determine the entire structural responses and the typical local stress in critical location of the SWATH ship,a 3-D coarse mesh finite element model representing of the entire vesel and 2-D fine mesh finite element models resprenting the the bulkhead and web frame are establishsd.The purpose of 3-D finite element model is used to get the overall response of the vessel based on its caargo and seaway loadings and showing in the form of stresses and displacements.Moreover,the nodal displacements denote the boundary conditions for the subsequent 2-D finite element analysis.Based on the 2-D finite element analysis,the detail local stresses analysis obtained. In the dynamic analysis,the free vibration analysis of the SWATH ship on still water surface and the dynamic responses of the SWATH ship with 20 knots forward speed in beam seas and head seas are considered. The coupled responses of rigid-body motions and elastic vibrations of the SWATH ship due to wave exciting forces are determined. The analytical approach for determing the motion and wave loads is based on the linear seakeeping theory and the assumption of the harmonic wave excitation.