Dynamic analysis of geared transmission system for wind turbines with mixed aleatory and epistemic uncertainties

This paper deals with the co-existence of mixed aleatory and epistemic uncertainties in a wind turbine geared system for more reliable and robust vibration analyses. To this end, the regression-based polynomial chaos expansion (PCE) is used to track aleatory uncertainties, and the polynomial surrogate approach (PSA) is developed to treat the epistemic uncertainties. This non-intrusive dual-layer framework shares the same collocation pool, which is extracted from the Legendre series. Moreover, the regression technique has been implemented in both layers to enhance calculation efficiency. Numerical validation is carried out to show the effectiveness of the proposed method. New vibration behaviors of the geared transmission system are observed, and the mechanism behind is discussed in detail. The findings of this paper will contribute to the insightful understanding of such wind turbine geared systems under hybrid uncertainties and are beneficial for the condition monitoring.