| Summary: | 碩士 === 國立臺灣海洋大學 === 系統工程暨造船學系 === 95 === Abstract
Owing to the large hatch opening in containerships, the hull structural loads should be taken into consideration of the wave induced vertical and horizontal shear forces, bending moments and wave torques. Whilst such kinds of wave induced loadings are pertaining to a long-term characteristics. In this dissertation, the panel method based on the three dimensional Green’s function are used to analyze the frequency response function of ship motion in waves through the software HSC-3D. Together with the Pierson-Moskowiz wave spectrum and Walden scatter diagram, the long-term extreme wave loads applied to ship hull can be attained in a period of twenty years. Comparisons of such wave loads with that regulated by the rules of ABS and LR are discussed. Besides, the stress analyses in a ship hull structure with large hatch openings have been performed both by the softwares ANSYS and WARSHP respectively. In which ANSYS is based on the FEM while WARSHP is based on the mulit-cell thin beam theory. Both analysis results are also compared in the same load condition generated by the same waves. From the compareisons of a real ship wave load analysis, it can be shown that the design vertical shear forces at midship obtained by ABS rule and long-term prediction of wave theory are very closed; the design torque obtained by LR rule is slightly lower than that by long-term prodiction; regarding the design vertical bending moment, ABS’s value is more closed to the long-term prediction than that of LR’s value; while the design horizontal bending moment, LR’s value is lower than that of the long-term prodition. Besides, form the comparisons of the stress distributions at 5 section of a real ship, i.e. 62m, 105.78m, 133m, 137.m and 164.9m from A.P., by FEM and thin-beam theory, it has shown that the distribution tendencies are similar but different in magnitudes.
Keywords : ship with large hatch opening, containership, long-term wave load prodiction, wave spectrum, transfer function, structure analysis, thin beam
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