【作者】 张晶；

【导师】 康海贵；

【作者基本信息】 大连理工大学 ， 港口、海岸及近海工程， 2010， 博士

【摘要】 结构可靠度分析包括构件和体系两个层次：构件层次的可靠度经过几十年发展已经成熟,进入了实用阶段；对结构进行体系可靠度分析虽然已经在工程界达成共识,但距实际应用还有一定的距离。主要原因是结构体系可靠度计算中的两大难点“主要失效模式的搜寻”与“体系失效概率的计算”还有待于进一步研究。本文针对“结构体系失效概率的计算方法”开展研究,得到以下主要成果：(1)针对基于条件概率的PCM方法(Product of Conditional Marginal)在构件可靠指标较大和失效模式间相关性较强时,计算串联体系失效概率误差较大的问题,提出了改进的PCM法。针对等价平面法(Equivalent Plane Method)计算并联体系失效概率误差较大的问题,提出了改进的等价平面法。(2)基于可靠指标矢量的概念,应用等价失效模式的思想,推导了两个失效模式串联、并联及条件等价失效模式的可靠指标矢量计算公式。用可靠指标矢量来确定体系可靠度计算过程中失效模式间的相关系数,进而推求结构体系的可靠指标矢量。(3)研究发现,在一定的可靠指标范围内串联体系和并联体系都具有对失效模式间的相关系数不敏感的特性。根据这一特性,提出在采用等价平面法计算结构体系可靠度时用各失效模式间的最大相关系数作为近似等价相关系数,简化了计算。(4)针对体系可靠度计算时,近似方法结果受计算顺序影响的现象,研究了几种体系可靠度计算方法的特点。提出了按失效模式相关性强弱和可靠指标大小分组计算体系失效概率的方法与原则。(5)根据分组计算体系失效概率方法和原则,通过可靠指标矢量来确定各组间的失效模式相关性,对实际工程进行了体系可靠度分析。更多还原

【Abstract】 The development of structural reliability analysis can be divided into two stages, component analysis stage and system analysis stage. After years of diligent research, the component reliability analysis has achieved quite good level and has been applied to the actual projects. Although most of the scholars reached an agreement that the structural system reliability should be spreaded and applied to the engineering, yet there are still quite long way to go for this aim. There are mainly two difficulties for the structural system reliability application:①how to search for the major failure modes?②how to calculate the structural system failure probability? This paper concentrates on the study of structural system failure probability calculation methods. The main research findings are as follows:(1) If the component reliability index is large and correlation of failure modes is strong, the PCM (Product of Conditional Marginal) method can usually cause quite large error for the series system failure probability calculation. So, a further improved PCM method (FIPCM) is proposed in this paper. The same problem also exists for the parallel system failure probability calculation if the EPM (Equivalent Plane Method) is used. So, an improved EPM method (IEPM) is also put forward.(2) Based on the conception of reliability index vector and the idea of equivalent failure mode, the reliability index vector formulae are deduced for the series system, parallel system and conditional equivalent failure modes. The correlation coefficient between the failure modes can be determined by the reliability index vectors, and then the structural system failure probability and reliability index vector can be obtained.(3) It has been found that the correlation coefficient between system failure modes is insensitive for the series and parallel system in a certain range of reliability indices. According to this characteristic, the maximum correlation coefficient between failure modes is taken as the approximate equivalent correlation coefficient when the equivalent plane method is used to calculate the structural system reliability.(4) Because the calculation accuracy of system reliability by the approximate method is strongly influenced by the calculation sequences, a grouping calculation method is proposed, in which the strength degree of correlations and the magnitude of reliability index are the main controlling factors. (5) The above mentioned principles and methods are applied to an actual project analysis, in which the grouping calculation method is used and the correlation of failure modes of groups are determined on the principle of reliability index vectors.更多还原