Models for blisks with large blends and small mistuning

The combined effects of large blends and small mistuning are studied using N-PRIME for a dual flow path system and for a conventional blisk. The accuracy of the N-PRIME method is validated against full-order finite element analyses for both natural and forced response computations, including displacement amplitudes and surface stresses. Results reveal that N-PRIME is capable of accurately predicting the dynamics of a blisk with severely large mistuning, along with small random mistuning throughout each sector. Also, N-PRIME can accurately capture modes with highly localized motions. A statistical analysis is performed to study the effects of random mistuning on both natural frequencies and forced responses and reveals that 1) new clusters of mistuned natural frequencies exist and cannot be treated as small deviations from nominal frequencies, and 2) unexpectedly high amplifications of forced responses exist, showing 3-5 times higher responses compared to the nominal system.