【作者】 韩晓双；

【导师】 马骏； 赵德有；

【作者基本信息】 大连理工大学 ， 船舶与海洋结构物设计制造， 2006， 硕士

【摘要】 处于海洋环境中的导管架平台，除了承受结构自重以及甲板设备重量等静荷载作用外，还经常受到诸如风、波浪、海流、地震、船舶撞击等各种环境动力荷载的作用，其中波浪和地震是两种比较典型的动力荷载。目前，波浪荷载作用下平台结构的动力反应研究的比较多，而对地震作用下海洋平台结构的反应分析还相对较少。虽然地震荷载没有波浪荷载和风荷载出现的频率高，且持续时间也很短，但是大的地震所造成的破坏却是非常严重的。本文分别应用反应谱法、时程分析法和随机振动法对导管架式海洋平台地震响应进行了研究，具体内容有： (1)对反应谱理论和相关概念进行了介绍，应用该方法对导管架式海洋平台地震响应进行了谱分析。通过Ansys软件计算了平台的自振频率，根据《海上固定平台入级与建造规范》中规定的地震响应谱对地震载荷进行了计算，通过振型组合考虑各振型分量对总响应的贡献，得到了地震响应最大值。 (2)详细介绍了时程分析方法的基本理论，包括参数选取、结构计算模型和计算步骤等方面的内容，系统地给出了有关场地土的类别和地震设防烈度的地震波选择，包括波的条数、形状、强度等方面参数的选取，具有一定的参考意义。应用Fortran语言，采用Wilson-θ逐步积分法编制了地震反应计算程序，对平台进行了一维时程响应分析，得到了地震响应时程。同时应用大型有限元软件Ansys对平台进行了三维时程响应分析。 (3)提出一种基于梁理论的海洋平台随机地震响应简化计算模型，应用哈密顿(Hamilton)原理推导了其在地震作用下的弯曲运动方程，采用里茨法与虚拟激励法相结合，推导了平稳和非平稳随机激励下各种响应量功率谱的计算公式，并用Matlab软件编制了程序，为海洋平台的抗震设计提供了参考。更多还原

【Abstract】 Jacket platforms located in the sea not only are subjected to static loads, such as gravity, deck, and equipment load, etc., but also endure dynamic forces including wind, wave, current, earthquake, and collision, etc. Among those dynamic excitations, wave and earthquake are two typical loads. At present, there are many studies on responses of platforms under wave load, whereas the studies on earthquake responses of platforms are relatively fewer. Although the arisen frequency of earthquake is lower than that of wave, and its standing time is also shorter than that of wave, the destroy level of great earthquake is rather severe.In this paper, seismic responses of jacket platforms are studied from three aspects based on three calculation methods of seismic responses as follows:First of all, the response spectrum method and some related concepts are expatiated by combining with the Criterion for Classifying and Constructing Fixed Offshore Platforms, and the spectrum analysis is given to a jacket platform.Secondly, some main contents on time-history analysis method are explained including the selection of parameter, structure model, and calculation process, especially the selection of earthquake wave which concerns the amount, shape, and intensity of seismic wave. Two illustrations are presented by programming based on the Wilson- θ method and applying the FEM software ANSYS.Finally, a simplified calculational model is brought forward for computing the random seismic responses of jacket platforms. Based on the Hamilton theory, the equation of bending motion is developed and solved by the classical Ritz method combined with the pseudo-excitation method, and then a program for computing random seismic responses is produced by using software MATLAB. Usually, random responses of this continuous structure are obtained by orthogonality of modes, and some normal modes of the structure are needed, causing inconvenience for the analysis of the non-uniform beam whose normal modes are not easy to be obtained. However, if the pseudo-excitation method is extended to calculate random responses by combining it with the classical Ritz method, the responses of a non-uniform beam, such as auto-PSD function, cross-PSD and higher spectral moments, can be solved directly avoiding the calculation of normal modes.更多还原