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Developmental Study on Structural Reliability Assessment Systems of Marine Structures

海洋结构物结构可靠性评估体系的发展研究

基本信息

批准号：
01850095
负责人：
OKADA Hiroo
金额：
$ 4.16万
依托单位：
University of Osaka Prefecture
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research (B).
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1990
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01850095/
关键词：
Marine frame structure Ultimate strength Dynamical effect Structural reliability Dominant failure mode Failure probability Importance factor Structural synthesis 立体骨組モデル経年変化

项目摘要

1. At first, applicabilities of the program package developed for reliability assessment of marine structures are investigated through numerical examples for two typical semi-submersibles, which are modeled as spatial frames and subjected to quasi-static extreme loads based on ultimate strength analysis. Results obtained in this study are summarized as follows :(1) The underlying theory and the system's overview are provided. (2) The applicability of the system is demonstrated through the numerical examples for structures under beam and oblique seas (3) Effects of some design alterations on system reliability are also discussed by introducing importance factors as reliability measures under a damaged condition.2. Next, methods are presented for the probabilistic analysis on the ultimate strength and the natural frequencies of composite and slender offshore structures for deep water, which are treated as a simple tower model by replacing its tower frameworks and platform with the beam-columns with equivalent stiffness and strength, respectively. A method is also presented for reliability assessment of aged marine structures considering increase of extreme wave loads due to marine growth and corrosion, and deterioration of rigidity and resistance due to corrosion. Further, the effect of uncertainty on the natural frequencies is discussed by using a probabilistic sensitivity analysis method. Finally, the applicability of the proposed methods is demonstrated through the numerical example for a 450m guyed tower.

1. 首先，通过两个典型半潜式潜水器的数值算例，研究了为海洋结构物可靠性评估开发的程序包的适用性，将半潜式潜水器建模为空间框架，并根据极限强度分析承受准静态极限载荷。本研究取得的成果总结如下：(1)给出了基础理论和系统概述。 (2)通过梁下结构和斜海结构的数值算例证明了该系统的适用性。(3)通过引入受损条件下可靠性措施的重要因素，讨论了一些设计变更对系统可靠性的影响。2．接下来，提出了深水复合材料和细长海上结构的极限强度和固有频率的概率分析方法，将其视为简单的塔模型，分别用具有等效刚度和强度的梁柱代替其塔架和平台。还提出了一种用于老化海洋结构可靠性评估的方法，考虑到由于海洋生长和腐蚀而导致的极端波浪载荷的增加，以及由于腐蚀而导致的刚度和抵抗力的恶化。此外，利用概率敏感性分析方法讨论了不确定性对固有频率的影响。最后，通过450m拉线塔的数值算例证明了所提方法的适用性。