摘要內容
| 年度卷號期數 | 2020年 39卷 1期 |
| 中文主題 | 雙體船在斜浪中的橫跨甲板負荷及結構分析方法 |
| 英文主題 | Cross Deck Load and Structural Analysis of Catamarans in Quartering Sea |
| 中文作者 | 施囿丞、林宗岳、李雅榮 |
| 英文作者 | Y.-C. Shih, T.-Y. Lin, Y.-J. Lee | 中文關鍵字 | 雙體船,橫跨甲板強度,有限元素分析,縱搖連接力矩 |
| 英文關鍵字 | Catamaran,Finite Element Analysis,Cross Deck Strength,Pitch-Connecting Moment | 中文摘要 | 本研究分析高速雙體船在斜浪下波浪負荷、結構響應以及其簡化方法。傳統的計算截面負荷方法為沿著船長方向積分，但對雙體船而言其橫向的負荷無法適用此方法。因此，本文將雙體船的浸水表面離散化成多個三角形的小板，並直接利用各個板上的靜水壓力疊加，得到每個任意截面的總負荷，而船的吃水狀況是用整艘船的重量和重心來調整其姿態。接著，將波浪引起的吃水變化用正值或負值的虛擬重量來表示其在波浪中對應的波谷或波峰狀態，求出橫跨甲板的縱搖連接力矩並與規範值進行比較，顯示本方法準確估算波浪負荷。在船體結構方面，本研究採用三種方法解析：全船有限元素模型、格柵式樑元素模型、以及基本材料力學之樑理論，模型複雜度與計算時間依序由高而低。使用上述縱搖連接力矩與三種結構方法分析兩艘目標船，一般雙體船和穿浪型雙體船，橫跨甲板及浮體的連接處在斜浪條件下的強度、位移與應力值皆可驗證結構簡化方法的合理性。 |
| 英文摘要 | This study uses a hydrostatic approach to calculate the pitch-connecting moment of catamarans caused by quartering waves, and establishes two simplified methods to assess the cross deck strength without building the full ship finite element model. Tradi-tionally, calculation of sectional loads is through integrating along longitudinal direction; for transverse loads for catamarans, this integral method is not applicable. In this study, the wetted surface of floating body is discretized into triangular panels, and the hydrostatic pressures on the panels are analytically calculated. The wave induced dis-placements at fore/aft bodies and port/star-board sides are treated as virtual masses of equivalent dis-placement changes, which located at centers of buoyancy. The section load can then be calculated pro-vided given weight distribution. The present method assessed the pitch-connecting moment of a catama-ran and a wave piercing catamaran under quartering sea condition, i.e. the torsion of the centerline longi-tudinal section, and compared with Rules. Full ship finite element models for the two ships were built for validating the proposed simplified methods, one is the lattice beam finite element model, and the other is the direct calculation using beam theory based on the assumption of a rigid demihull. The deflection and stress distribution of each method is verified against the results from full ship finite element model, but for discontinuities of structures, such as the bow and stern of the wave piercing catamaran, the beam method was erro-neous. In addition, both simplified methods cannot resolve stress concentrations at the openings on the deck. These disadvantages are going to be addressed in the future. |
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