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传统的结构体系可靠度分析方法依赖于结构失效路径的分枝和约界技术,导致主要失效模式难以识别、体系失效概率计算工作量巨大.鉴于此,本文结合弹性模量缩减法和随机有限元法,提出了一种不依赖失效路径的结构体系可靠度分析方法.首先利用随机有限元法计算结构的随机响应量,据此定义单元承载比和基准承载比,以判别结构在不同受力状态下的高承载单元.然后利用变形能守恒原理建立结构内力重分布和损伤演化模拟的随机弹性模量缩减法,进而根据塑性极限状态下高承载单元的弹性模量缩减幅度确定结构主要失效模式,并利用多失效模式的联合失效概率计算结构体系可靠度.研究表明,该方法消除了传统方法中潜在失效路径对主要失效模式识别和失效概率计算的干扰,能够取得更高的计算效率和精度.
The traditional method of reliability analysis of structural system relies on the branches and the approximation technique of structural failure paths, which makes it difficult to identify the main failure modes and huge workload in the calculation of system failure probability.In view of this, combining elastic modulus reduction method and stochastic finite element method , A reliability analysis method of structural system that does not rely on failure path is proposed.Firstly, the stochastic finite element method is used to calculate the random response of the structure, thus the unit bearing ratio and the reference bearing ratio are defined to determine the structure under different stress conditions And then use the theory of conservation of energy to establish the stochastic elastic modulus reduction method for the structural internal force redistribution and damage evolution simulation, and then determine the main failure mode of the structure according to the reduction range of the elastic modulus of the high load-bearing unit in the plastic limit state The reliability of the structural system is calculated by the joint failure probability of multi-failure modes.The results show that the proposed method can eliminate the interference caused by the potential failure path in the traditional method to identify the main failure modes and calculate the failure probability, and achieve higher computational efficiency and accuracy.