STUDIES ON RELIABILITY ANALYSIS SYSTEMS OF SHIP HULL STURCTURES

本文研究的是船舶船体结构可靠性分析系统。本研究取得的主要结果如下：1.对船体梁各部位在纵向弯曲应力和侧向压力作用下的加筋板抗压强度进行了可靠性分析。从可靠性的角度比较了各种强度方程的结果。分析了一些设计参数对可靠性指标的影响.在此基础上，采用空间膜单元模型，对某大型散货船（15万吨级）的结构可靠性进行了模态分析.分析结果表明，在船体结构的前/后L/4部分，剪应力和侧压力对包括舷侧单元损伤在内的主要破坏模式及其发生概率的影响要比在船体中部更为显著.文中还指出，另一种参考船级社报告中考虑名义腐蚀损伤的劣化结构计算结果，与老龄散货船前后部结构腐蚀损伤的特点有较好的对应性.提出了一种新的框架-板组合结构体系，拓展了海洋结构物结构体系可靠度的适用范围.本文还提出了一种基于变载荷模拟技术的海洋空间结构在非线性和不规则波浪载荷作用下的疲劳可靠性分析方法。

This study is concerned with structural reliability analysis systems of ship hull structures. Results obtained in this study are summarized as follows :1. Reliability analysis for compressive strengths of stiffened panels under longitudinal bending stress and lateral pressure is performed at various parts of the hull girder. The results for various strength equations are compared from a viewpoint of reliability. Effects of some design parameter sensitivity analysis for the reliability index.2. The features of structural reliability of a large bulk carrier (150,000DWT) based on the collapse mode analysis are investigated by successively applying the newly developed system for plate structures using a spatial membrane element model in the previous studies.3. From the analytical results, effects of shearing stress and lateral pressure on dominant collapse modes including damages of side shell elements and their occurrence probabilities in the fore/aft L/4 parts of the ship hull structure are more remarkable than in the midship part.4. It is also pointed out that anothert results for deteiorated stuctures considering the notional corrosion damage referred to the classNK report report are in comparatively good correspondence to the features of structural damages due to corosion at fore/aft parts of aged bulk carriers.5. A new system for combined frameworks and plate structures is considered to offer the expansion of applicability of structural system reliability of marine structures.6. A method using varying load simulation techniques is also developed for fatigue reliability analysis of marine space structures under nonlinear and irregular wave induced loads.