桩基模型对自升式平台动力响应影响研究

发布时间：2018-06-22 09:55

本文选题：自升式平台 + 有限元　；参考：《大连理工大学》2016年硕士论文

【摘要】：较深海域的自升式平台需要考虑波浪等环境因素导致的动力效应,海底土体对桩腿的约束作用在平台动力响应分析中起着非常关键的作用,本文考虑海底土体与桩靴的作用建立了桩土、铰接、固支和API四种桩基模型,分别应用在参考“麦哲伦”号平台建立自升式平台有限元动力模型中,在ANSYS下对四种模型作模态分析和瞬态动力分析,比较得到的振动频率、振型和主船体位移等动力响应,验证了桩土桩基模型在平台动力响应分析中应用的有效性和合理性。使用单自由度法和时域分析法计算了平台动力放大系数DAF,比较不同波浪周期下两种方法计算DAF的差异,分析和总结差异产生的有原因。本文的桩土桩基模型中非常重要的参数有土体不排水抗剪强度、土体建模范围和桩靴最大直径,本文分别研究上述参数对自振频率、主船体位移和动力放大系数DAF等平台动力响应的影响,分析总结不同参数下动力响应的变化规律,根据结果对桩基建模和桩靴直径选取提出了一些建议。本文分析了桩土桩基平台有限元模型下,平台结构几何非线性P-△效应对平台动力响应分析的影响,证明P-△效应对平台自振频率、主船体位移和动力放大系数等动力响应有不可忽视的作用,应该在自升式平台有限元动力模型中准确考虑。
[Abstract]:The dynamic effect caused by wave and other environmental factors should be considered in the jack-up platform in deep sea area, and the restraint action of the bottom soil on the pile leg plays a very important role in the dynamic response analysis of the platform. In this paper, considering the interaction between submarine soil and pile boots, four pile foundation models, pile soil, hinge, fixed support and API, are established and applied to the finite element dynamic model of jack-up platform with reference to "Magellan" platform, respectively. The modal analysis and transient dynamic analysis of the four models are carried out under ANSYS. The dynamic responses such as vibration frequency, vibration mode and displacement of the main hull are compared, which verifies the validity and rationality of the pile-soil pile model applied in the dynamic response analysis of the platform. The dynamic magnification factor (DAF) of the platform is calculated by using the single degree of freedom method and the time domain analysis method. The difference of DAF between the two methods under different wave periods is compared, and the reasons for the difference are analyzed and summarized. In this paper, the most important parameters of pile-soil pile foundation model are undrained shear strength, modeling range and maximum diameter of pile boots. The influence of the displacement of the main hull and the dynamic magnification factor (DAF) on the dynamic response of the platform is analyzed and summarized. Based on the results, some suggestions on the pile foundation modeling and the selection of the diameter of the pile shoe are put forward. In this paper, the influence of the geometric nonlinear P- effect of the platform structure on the dynamic response of the platform under the finite element model of pile-soil pile foundation platform is analyzed, and it is proved that the P- effect affects the natural vibration frequency of the platform. The dynamic responses such as the displacement of the main hull and the dynamic magnification factor can not be ignored and should be considered accurately in the finite element dynamic model of the jack-up platform.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U674.38

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