船舶结构屈曲失效分析中的主,客观不确定性的确定方法

根据船舶结构屈曲承载能力可靠性分析的需要，提出了一种客观不确定性系数的确定方法。该方法极其简单，而且具有泰勒级数展开法的精度，并能降低罗森布鲁斯法的计算量。在基本随机变量参数已提供的前提下，可以很方便地获得屈曲承载能力的统计特征值。本文还提出了两种主观不确定性系数的确定方法：一种为用于若干不同结构试验，但具有相同计算方法的“直接确定法”；另一种为用于若干相同结构试验，但具有同一计算特征值的“间接确定法”。文章还根据22只试验结果，采用两种计算方法2]3]，用“直接确定法”提供了两种主观不确定性系数的均值和变异系数。本文还提供了一种方法，根据主观不确定性的两个参数，可对计算方法进行评价。

DETERMINATION OF SUBJECTIVE AND OBJECTIVE UNCERTAINTIES IN BUCKLING FAILURE ANALYSIS OF SHIP STRUCTURES

An approach to the determination of objective uncertainties is presented to meet the needs of ship structure reliability analysis based on buckling-load carrying capacity. The proposed method is simple and has the same accuracy as using the Taylor expansion. In addition, employment of this method will reduce the computation load and it can be easily used for analysis uncertainties, if a deterministic method for calculation is available. In case of the basic random variables are known, the statistical characteristics of bucklingload carrying capacity can readily be obtained.Two methods for determining the subjective uncertainty are also suggested. The one is called "method of direct determination,), which can be applied to the tests for several different structures, and the other, "method of indirect determination", which can be applied to the tests for identical structures with same statistical characteristics. Based on the results of 22 tests and by using two calculation methods, the mean values and C. O. V. s for two subjective uncertainties using the "method of direct determinationn are provided.These two subjective uncertainties can be applied to the ship structure reliability analysis in buckling failure mode, provided that the corresponding calculation method are used.Based on two parameters of subjective uncertainty, an assessment for the calculation method is also discribed.