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Analysis of Wave Loads on A Semi-Submersible Platform 总被引:10,自引:0,他引:10
For the global and structural fatigue strength analysis of a semi-submersible platform, wave loads under design conditions are calculated by use of the three-dimensional boundary element method. Methods for calculating the forward-speed free-surface Green function are discussed and a computer program with this Green function is developed. According to the special rules, the wave loads under several typical design conditions of the platform are calculated. The maximum vertical bending moment, torsion moment and horizontal split force are determined from a series of contour maps of wave loads for the wave period of 5 to 18 seconds at a certain interval and the wave phase of 0°to 360°at a certain interval. The wave height is determined by the function of wave period with a given exceedance probability. The maximum wave loads under the combination of wave parameters are used as the input of hydrodynamic pressure in the three-dimensional finite element analysis process. The transfer functions of wave loads 相似文献
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超临界CO_2由于诸多的优良特性,在非常规天然气资源的开采上具有经济技术优势。为了定量研究CO_2与超临界CO_2对致密砂岩气储层裂隙结构与力学性质的影响,采用声发射与低场核磁共振技术研究了在CO_2与超临界CO_2作用下15 d砂岩的损伤行为。结果表明:CO_2组和超临界CO_2组单轴强度均降低,且超临界CO_2组降低明显。超临界CO_2组在弹性阶段就产生大量声发射信号;CO_2组与超临界CO_2组的累计声发射计数曲线上升点(裂隙闭合与裂隙发育分界点)均出现在更小的应变阶段;所有试件的声发射能量概率密度P(E)都较好地满足幂定律,CO_2与超临界CO_2浸泡并不改变砂岩声发射能量的尺度不变性。超临界CO_2组拥有更为倾斜的概率密度曲线,反映其小能量声发射信号所占比例增加;超临界CO_2组核磁T2波谱波形改变,其孔隙率与氢质子核磁信号均有明显增加。 相似文献
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