Reseach on Strength of Ships and Offshore Structures Sbujected to Hydrostatic Pressure.

船舶及海洋结构物静水压强度研究。

基本信息

批准号：
61302049
负责人：
OHTSUBO Hideomi
金额：
$ 9.92万
依托单位：
University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Co-operative Research (A)
财政年份：
1986
资助国家：
日本
起止时间：
1986 至 1988
项目状态：
已结题

项目摘要

In order to obtain critical pressure to cause general instability of reinforced cylindrical shells, the buckling equations were derived based on the energy method. The buckling pressure is calculated and compared with the experimental ones indicating good accuracy of analytical model. Recent advances of numerically controlled machining ennable us to estimate buckling pressure of sttifend sylindrical shells accurately by experiments. Machined models can regarded as perfectly cylindrical shells, and the validity of modelling for numerical method will be abl to confirmed by comparing theoretical results with experiment. in order to analyse the ultimate strength of ship and offshore structures, idealized "plate element" and "stiffend element" in the framework of the idealized structural unit method (ISUM) were deceloped. A simple calculation method is developed to simulate the progressive collapse behavior of a cross section of a ship's hull under longitudinal bending moment. The dynamic pulse lateral bucling of a T-shaped section thin walled beam and the effectiveness of asymetric section steffners in large deflection due to static loads were studied by expriments with simplified calculations. A system is developed for probabilistic strength assessment of semi-submersibles under the extreme sea. Through numerical examples for a typical platform, the properties of critical section or dominant failure modes and their probabilities of occurrence are investigated. Crush analysis codes of structural members have been developed by using low-order finite elements, which have been applied to The analysis of the crushing behaviors of steel tubes as well as the collapsing behaviors of ring-stiffened circular cylinders subjected to external pressure. the validities of the developed codeshave been demonstrated through the comparisons of numerical results with the experimental observations.

为了获得引起加固圆柱壳整体失稳的临界压力，基于能量法推导了失稳方程。计算了屈曲压力并与实验结果进行了比较，表明分析模型具有良好的准确性。数控加工的最新进展使我们能够通过实验准确地估计加强圆柱壳的屈曲压力。加工模型可以视为完美的圆柱壳，通过理论结果与实验的比较可以证实数值方法建模的有效性。为了分析船舶和海洋结构物的极限强度，在理想化结构单元法（ISUM）框架下开发了理想化的“板单元”和“加强筋单元”。开发了一种简单的计算方法来模拟船体横截面在纵向弯矩作用下的渐进倒塌行为。通过简化计算实验，研究了T形截面薄壁梁的动态脉冲侧向屈曲和非对称截面加强筋在静载大挠度作用下的有效性。开发了一种用于极端海域下半潜式潜水器概率强度评估的系统。通过典型平台的数值例子，研究了关键部分或主要失效模式的特性及其发生概率。利用低阶有限元开发了结构构件压溃分析规范，应用于钢管压溃行为以及环加强式圆柱体在外压作用下的压溃行为分析。通过数值结果与实验观察结果的比较，证明了所开发代码的有效性。