A Study on Efficient Methods for Estimating Strength and Reliability and Their Application to Preliminary Structural Design of Large Floating Structures

强度和可靠性有效估算方法及其在大型浮动结构初步结构设计中的应用研究

基本信息

批准号：
15360469
负责人：
OKADA Hiroo
金额：
$ 6.4万
依托单位：
OSAKA PREFECTURE UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

项目摘要

1)Efficient methods are investigated for estimating strength and reliability of pontoon type VLFS under long crested waves from view point of preliminary design by analysis. Firstly, a simplified estimation method is presented for the probabilistic load effect of VLFS under irregular sea-state conditions. Next, a limit state and reliability analysis method is presented for the buckling and ultimate collapse strength of stiffened panels under combined compression, shear and lateral pressure in deck, bulkhead and bottom parts of VLFS. Then, the validity of the simplified estimation method is shown by using non-linear finite element analysis. The applicability of the methods is investigated through numerical examples for 5,000m-class VLFS under trial design for the severe sea state-condition in Tokyo Bay. Effects of design parameters such as plate thickness, stiffener and bulkhead space on characteristics of the reliability level are numerically shown by using sensitivity analysis.2)An ef … More ficient method is presented for estimating hydro-elastic behavior of VLFS modeled by a rectangular plate on the shallow water in oblique waves. Effects of incident wave-number, incident angle, aspect ratio and bending rigidity of the structure on the response behavior are investigated.3)Fatigue behavior of structural steels under multiple repeated loads as a part of basic studies on fatigue life estimation of marine structures. The fatigue behaviors such as the change of hysteresis loop energy and temperature rise rate of specimens under completely reversed tension and compression are investigated with much circumstance. A method for estimating the remaining fatigue life is presented by using a method combined the linear cumulative fatigue damage rule (Miner's rule) with above experimental results.4)The compressive ultimate strength of stiffened plates with corrosion is investigated by the non-linear finite element method. It is found that the ultimate strength is determined by the parameters of the most corroded cross section of stiffened plates. Simple design equation to estimate the ultimate strength is proposed by considering above results.5)Simplified method is presented for estimating the residual strength of corroded circular tubes under bending and compression. It is found that the above estimation results for effects of the reduced thickness due to corrosion on the ultimate strength deterioration are in comparatively good correspondence to analytical results based on elasto-plastic finite element method using shell elements. Less

1）研究了有效的方法，以通过分析的初步设计的角度来估算长长的波浪中浮桥的强度和可靠性。首先，提出了一种简化的估计方法，用于在不规则的海态条件下VLF的概率负载效应。接下来，提出了一种极限状态和可靠性分析方法，用于在甲板，隔板，隔板和VLF的底部组合压缩，剪切和侧向压力下的屈曲和最终塌陷强度。然后，通过使用非线性有限元分析显示了简化估计方法的有效性。该方法的适用性是通过在东京湾严重的海洋国家条件下的5,000m级VLF的数值示例进行研究的。通过使用灵敏度分析，在数值上显示了设计参数，例如板厚度，加强剂和舱壁空间对可靠性水平的特性的影响。2）EF…提出了更高的方法，用于估算VLFS在浅水中的矩形板上模拟的VLF的弹性行为。研究了结构的入射波数，入射角，纵横比和结构弯曲刚度对响应行为的影响。3）在多个重复载荷下结构钢的疲劳行为，这是海洋结构疲劳寿命估计的基础研究的一部分。疲劳行为，例如在完全逆转的张力和压缩下的磁滞回路能量的变化以及样本的温度上升速率。通过使用一种将线性累积疲劳损伤规则（矿工规则）与上述实验结果相结合的方法来介绍估计剩余疲劳寿命的方法。4）非线性有限元方法研究了具有腐蚀的僵硬板的压缩最终强度。发现最终强度取决于僵硬板的最腐蚀横截面的参数。简单的设计方程式以估计最终强度是通过考虑上述结果提出的。5）简化的方法提出了用于估算弯曲和压缩下腐蚀圆形管的残余强度。发现上述估计结果对使用壳元素基于弹性塑料有限元法基于弹性塑料有限元法的分析结果的较小厚度对最终强度定义的影响的影响相对较好。较少的