• 作者： 吳重雄；林朝福
• 作者服務機構： 國立成功大學造船及船舶機械工程學系
• 中文摘要： 本文旨在研究以鋼筋混凝土做的重力式鑽油台，在規則波浪作用下之動力反應。全文包括三個主要部份：一為上層結構（Superstructure)之自由振動分析。此處吾人使用轉移矩陣法來求上層結構物之自然頻率與相對應之振動模態。轉移 矩陣法非常適用於重力式鑽油台之自由振動分析，因其具有直接性及小電腦貯存量之優點。二?探討波浪作用於結構物上 之激振力。由於重力式鑽油台之腿部（legs)與沉箱（caisson)之尺寸相差懸殊，故作用於腿部之波力可用傳統的莫利森 方程式（Morison's Eq.)求之，但作用於沉箱上的波力則須用繞射理論（diffraction theory)來決定。三?使用模態重 疊法來估計鑽油台在規則波浪作用下之動力反應。此處之所以使用模態重疊法，乃因本法較一般的直接積分法有更高的效 率，特別是當結構複雜龐大，而阻尼問題亦難以解決時，本法更能顯示其優點。第三部份之重點，在研究一些主要波浪因 數，如波浪行進方向及波長等對結構物動力反應之影響。
• 英文摘要： The dynamic responses of the reinforced concrete gravity structure due to regular wave excitation are studied. The report may be divided into three major parts: Firstly, the free vibration of the superstructure is analyzed. In this analysis the transfer matrix method is used to determine the natural frequencies and the corresponding mode shapes of the superstructure. It is found that the transfer matrix method is one of the most effective techniques for the free vibration analysis of gravity platform because of its straightforwardness and small computer storage. Secondly, the wave-induced exciting force on the structure is investigated. The excitation on the legs is evaluated by the conventional Morison's equation, while that on the caisson is estimated by the diffraction theory. Thirdly, the dynamic responses of the platform are predicted by the mode superposition method, which is deemed more efficient than the direct integration method, particularly when the structure is complicated and the damping problem is concerned. In this final part, attention is primarily directed toward looking for the influence on the responses of the key parameters such as directions of wave propagation, wave lengths, etc.
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