An enhanced multi-fidelity Gaussian process framework for efficient time-variant reliability analysis
摘要
The reliable estimation of time-variant failure probabilities in complex engineering systems poses a significant computational challenge, primarily due to the substantial number of high-fidelity model evaluations required by conventional Monte Carlo simulation. This work presents an enhanced multi-fidelity Gaussian process (EMFGP) active-learning framework that enables reliable estimation of time-variant failure probabilities while significantly reducing the number of required high-fidelity model evaluations. The main idea is to combine a low-fidelity model that captures general trends with a high-fidelity correction model that accounts for finer, more critical details. One of the key contributions of this work is a flexible kernel function (covariance structure) that allows the surrogate model to capture both broad spatial features and intricate time-dependent behavior within a single formulation. To improve reliability, particularly when the available data are sparse or nearly deterministic, this study adopts a variance-controlled, data-driven initialization strategy. This helps stabilize hyperparameter learning and prevents numerical instability during model training. Across five examples, EMFGP achieved similar reliability accuracy to Monte Carlo simulations while using around 20–30% fewer high-fidelity evaluations, and up to 40% fewer in cases where the low-fidelity model shows strong correlation. This highlights the method’s efficiency and suitability for time-dependent reliability analysis, especially when high-fidelity simulations are costly.