Abstract
In practical engineering, due to the lack of information, it is impossible to accurately determine the distribution of all variables. Therefore, time-variant reliability problems with both random and interval variables may be encountered. However, this kind of problem usually involves a complex multilevel nested optimization problem, which leads to a substantial computational burden, and it is difficult to meet the requirements of complex engineering problem analysis. This study proposes a decoupling strategy to efficiently analyze the time-variant reliability based on the mixed uncertainty model. The interval variables are treated with independent random variables that are uniformly distributed in their respective intervals. Then the time-variant reliability-equivalent model, containing only random variables, is established, to avoid multi-layer nesting optimization. The stochastic process is first discretized to obtain several static limit state functions at different times. The time-variant reliability problem is changed into the conventional time-invariant system reliability problem. First order reliability analysis method (FORM) is used to analyze the reliability of each time. Thus, an efficient and robust convergence hybrid time-variant reliability calculation algorithm is proposed based on the equivalent model. Finally, numerical examples shows the effectiveness of the proposed method.
Highlights
Structural reliability is regarded as the ability of the device or structure to complete the required functions under the specified conditions within the prescribed design period [1,2,3,4,5]
It should be indicated that the interval variable is treated with the uniform distribution, which is regarded as a random variable. in this situation, the limit state function of the time-variant reliability model with mixed uncertainties only contains random variable
(2) The interval variable Y is treated as a uniform distribution, which is regarded as a random variable
Summary
Structural reliability is regarded as the ability of the device or structure to complete the required functions under the specified conditions within the prescribed design period [1,2,3,4,5]. In order to resolve this shortcoming, Andrieu Renaud et al [15] transformed the calculation of the outcrossing rate into the reliability problem of a static parallel system and established the pHi2 method They provided a good scheme to determine the span rate efficiently and analyze the time-variant reliability. The computational efficiency is extremely low, which adversely affects its practicability in industrial applications To this end, it is vital to develop efficient algorithms to significantly decrease the computational burden of the time-variant reliability method with mixed variables. It is intended to presented a novel approach to analyze the structural time-variant reliability with mixed variables To this end, the existing timevariant reliability theory is combined with the interval uncertainty analysis.
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