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运用 FORM或SORM法进行结构系统的疲劳可靠性分析中,失效途径(并联系统)以及由一系列失控途径串联而成的复合系统的失效概率的计算最终要归结到对n维标准正态分布函数Φ_n((?),[ρ])的计算,当维数n较大时,直接采用数值积分方法计算工作量极大,且累积计算误差也不容忽视.因此,本文引进了Hohen-bichler提出的将Φ_n((?),[ρ])逐级降阶为单重积分运算的近似算法,并把它与FORM法进行了有效的结合.通过简单的算例验证了Hohenbichler方法的可靠性和高效率后,本文对一简化的海洋平台结构系统的疲劳可靠性进行了分析计算,结果表明,Hohenbichler方法在保证足够精度的前提下,极大地提高了计算效率,是一种在结构系统可靠性分析领域值得推荐的方法.
In the fatigue reliability analysis of structural system by using FORM or SORM method, the calculation of the failure probability of failure system (parallel system) and composite system composed of a series of runaway routes concludes with the analysis of n-dimensional standard normal distribution function Φ_n ((?), [Ρ]), when the dimension n is large, it is very computationally expensive to directly use the numerical integration method, and the cumulative calculation error can not be neglected.Therefore, this paper introduces the Hohen-bichler The approximation algorithm of Φ_n ((?), [Ρ]) is reduced step by step to the single integral operation, and it is effectively combined with the FORM method.The reliability and highness of the Hohenbichler method are verified by a simple numerical example After the efficiency, this paper analyzes and calculates the fatigue reliability of a simplified offshore platform structural system. The results show that the Hohenbichler method can greatly improve the computational efficiency under the premise of ensuring sufficient accuracy. The field is worth recommending.