open access

https://hdl.handle.net/2115/100427

Reliability function analysis of a linear oscillator subjected to non-Gaussian random excitation using the equivalent non-Gaussian excitation method and the Hermite moment model

英語

Tail heaviness

2026-07-01

Proceedings of the 10th International Symposium on Reliability Engineering and Risk Management (ISRERM 2026)

This study develops an approximate analytical technique for evaluating the reliability function of a single-degree-of-freedom linear system subjected to non-Gaussian random excitation. The excitation is modeled as a stationary stochastic process characterized by an arbitrary probability density function (PDF) and a power spectral density (PSD) with a bandwidth parameter, and is described by an Itô stochastic differential equation. In the proposed approach, the equivalent non-Gaussian excitation method is first employed to derive moment equations of the system response, enabling the evaluation of response moments up to the fourth order. Based on these response moments, the Hermite moment model is then used to estimate the mean upcrossing rate of the displacement response under two approximations: statistical independence between displacement and velocity responses, and Gaussianity of the velocity response. The reliability function associated with first-passage failure is subsequently determined from the mean upcrossing rate by assuming that threshold crossings follow a Poisson process. Numerical examples demonstrate that the proposed method accurately estimates the reliability function for various excitation PDFs with different tail heaviness. Furthermore, it is shown that heavier-tailed excitation PDFs lead to lower system reliability.

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