摘 要随着人类社会的进步,开发海洋资源步伐在不断加快,自升式平台成为了海上油气资源勘探、开采的重要技术装备。然而,恶劣的海洋环境载荷会使自升式平台产生过大的船体位移及速度,从而发生屈服及断裂失效,且长期的船体振动使得平台极易发生疲劳失效现象;因此,自升式平台的动态响应特性将关系到整个平台的工作安全性能。本文首先研究了Super M2自升式平台桩腿的力学性能,并基于Abaqus/Aqua模块分析了自升式平台的动态响应特性。其主要研究内容及结论如下:lf0075
1)首先研究了论文涉及的基础理论,包括波浪理论。波浪理论部分包括线性波浪理论、斯托克斯波理论和微幅波浪理论,给出了它们对应的基本公式,为后面的理论模型以及有限元分析提供了强力的理论基础。
2)其次阐述了自升式平台的模态分析是船舶与海洋结构物固有特性分析的重要方法,介绍了模态分析方法的基本理论以及模态分析的基本方法。
3)接着介绍了自升式平台的建模方法及相关结构参数,通过模态分析得到了自升式平台的前十阶固有频率及振型图,基于Stokes波浪理论分析了站立工况下自升式平台的动态响应。
4)最后介绍了时域(锤击法)的自升式平台模态试验方案和过程。时域的自升式平台模态试验是使用的单点分区激励多点三向拾振的测试方法,锤击法具有快速、简捷、易操作等优点,但是对人为的操作技术有较高的要求。锤击法试验中激励点的选取对实验结果十分重要。此外锤击方向还要和自升式平台的三个坐标都要成一定的角度。
关键字:自升式平台;动态响应;桩腿;Abaqus/Aqua;锤击法
Abstract
As human development of marine resources continues to accelerate the pace, jackup offshore oil and gas resources has become the exploration and exploitation of important technical equipment. However, the harsh marine environment load will jackup excessive hull displacement and velocity, which occurred in the yield and fracture failure, and so long hull vibration platform prone to fatigue failure phenomenon; therefore, jack-up platforms dynamic response characteristics will be related to work safety performance of the entire platform. This paper studied the mechanical properties of Super M2 jack-up platform leg, and based on Abaqus / Aqua module analyzes the dynamic response of jackup platform. The main research contents and conclusions are as follows:
1) First, the basic theory research papers involved, including the wave theory. Wave theory part comprises a linear wave theory, theory and slightly Stokes wave theory, given their corresponding basic formula, the theoretical model and the finite element behind provided strong theoretical basis of the analysis.
2) The second section describes the important ways from the modal analysis jack-up platform is a ship and marine structures inherent characteristic analysis, introduces the basic theory of modal analysis method, and the basic methods of modal analysis.
3) then introduces the self-modeling and jack-up platform structure parameters, obtained by modal analysis of the top ten natural frequencies and mode shapes Figure jackup based Stokes wave theory to analyze the standing condition since dynamic Response elevating platform.
4) Finally, the time-domain (hammering) the jackup modal testing programs and processes. Jackup modal test is a single point in time domain partition incentive to pick-up three multi-point test method, hammering method is fast, simple and easy operation, etc., but the artificial technique has a high claim. Select hammering test excitation point on the experimental results is very important. Also hammering and three coordinate directions but also self-elevating platforms should be angled.