结构可靠性分析中结构能力统计特征的正确确定

摘要

Reliability methods have gained more and more popularity in ship structure community.In carrying out the reliability analysis of existing ship structures or implementing reliability based design rules for new ships, it is a necessary prerequisite to determine the statistical characteristics for both capacity and demand. In the current literature,some inconsistencies exist among the concepts and methods used to determine the structural capacity statistics. In this paper an attempt is made to clarify some concepts and methods.Two types of random variables i.e.dependent and basic,have been specifically distinguished.A new method which can efficiently and accurately calculate the mean and standard deviation of a dependent random variable is proposed.The consequences of some incorrect procedures and negligence of some information have also been discussed.Useful conclusions have been drawn.%在船舶结构界可靠性方法已得到越来越广泛的应用。在进行现有船舶的可靠性分析或对新船制订可靠性设计规范时，必须要首先确定能力与载荷的统计特征。在已发表的文献中，用于确定结构能力统计特征的方法甚至基本概念并不十分统一。本文旨在对有些概念和方法作一澄清。两类随机变量必须要区分开，即基本随机变量和从属随机变量。对于从属随机变量统计特征的确定，本文介绍了一种精确高效的确定其均值和标准差的方法。本文还对一些不正确步骤以及忽略某些信息带来的后果进行了讨论，归纳出了一些可供参考的结论。