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Ultimate Strength of Offshore Structures (Mainly Jack-up Rigs)

海上结构物的极限强度（主要是自升式钻井平台）

基本信息

批准号：
59460127
负责人：
UEDA Yukio
金额：
$ 4.1万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1984
资助国家：
日本
起止时间：
1984 至 1986
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-59460127/
关键词：
Offshore structure Jack-up rig Pipe structure Joint Dent Rigidity Ultimate strength 理想化構造要素法

项目摘要

Based on the Idealized Structural Unit Method, an ultimate strength analysis method was developed for the safety check of earthbound offshore structures. By this method the behaviors of the structures reaching ultimate strength under various loading conditions were investigated with consideration of the effects of local rigidity and strength.The object structure was divided into such elements as (1) joint, (2) pipe between two adjacent joints and (3) substructures composed of joints and pipes.T-joint consisting of cord and brace was assumed as the basic joint. Systematic theoretical and experimental studies were carried out on the rigidity and strength. As a result, simple estimating equations for the rigidity and ultimate strength were formulated.With this information, a new idealized structural unit, tubular joint element, consisting of springs, rigid bars and beam element was developed for T, Y and K joints in order to efficiently treat the local rigidity and strength in the whole structure analysis.Idealizing the elastic-plastic large deflection behavior of a pipe, an idealized pipe element was developed. Also, a similar element was developed for dented pipes.Using the above three idealized structural units, ultimate strength analyses were conducted for the whole structure of a jack-up rig and a jacket rig. Obtained were the following conclusions. (1) When the whole structure undergoes shear collapse due to horizontal load, ultimate strength is attained by yielding of the joints or buckling of the braces under compression depending on relative strength between the joints and braces. (2) The joint rigidity greatly influences the whole structural rigidity and ultimate strength. In addition, performing analyses of ultimate strength of a jack-up rig under survival and punch-through conditions, the safety of the structures in these cases was checked.

基于理想结构单元法，提出了一种适用于陆上海洋结构物安全校核的极限强度分析方法。该方法考虑了结构局部刚度和强度的影响，将结构划分为节点、节点之间的管道和由节点和管道组成的子结构，并以由索和支撑组成的T型节点为基本节点，研究了结构在各种荷载作用下达到极限强度时的受力性能。对该结构的刚度和强度进行了系统的理论和实验研究。在此基础上，提出了由弹簧、刚性杆和梁单元组成的T型、Y型和K型管节点的理想化结构单元--管节点单元，以有效地处理整体结构分析中的局部刚度和强度，并将管节点的弹塑性大挠度行为理想化，建立了管节点单元的弹塑性大挠度模型，并对管节点单元的弹塑性大挠度行为进行了分析，得到了管节点单元的弹塑性大挠度模型。开发了理想化的管元件。采用上述三种理想结构单元，对自升式钻井平台和导管架钻井平台的整体结构进行了极限强度分析。得出了以下结论。(1)当整个结构由于水平荷载而发生剪切破坏时，根据节点和支撑之间的相对强度，通过节点的屈服或支撑在压力下的屈曲来获得极限强度。(2)节点刚度对结构的整体刚度和极限承载力影响很大。此外，对某自升式钻井平台在生存和穿通条件下的极限强度进行了分析，校核了结构在这些情况下的安全性。