TY - GEN
T1 - Identification of mistuning characteristics of bladed disks from free response data-Part II
AU - Mignolet, Marc
AU - Delor, Jason P.
AU - Rivas-Guerra, Alejandro
PY - 1999
Y1 - 1999
N2 - The focus of the present investigation is on the estimation of the dynamic properties, i.e. masses, stiffnesses, natural frequencies, mode shapes and their statistical distributions, of nabomachine blades to be used in the accurate prediction of the forced response of mistimed bladed disks. As input to this process, it is assumed that the lowest natural frequencies of the blades alone have been experitneatally measured, for example in a broach block test. Since the number of measurements is always less than the number of unknowns, this problem is indeterminate in nature. Three distinct approaches will be investigated to resolve the shortfall of data. The first one relies on the imposition of as many constraints as needed to insure a unique solution to this identification problem. Specifically, the mode shapes and modal masses of the blades are set to their design/timed counterparts while the modal stiffnesses are varied from blade-to-blade to match the measured natural frequencies. The second approach, based on the maximum likelihood principle, yields estimates of all the structural parameters of the blades through the minimization of a specified "cost function". Finally, the third approach provides a bridge between the first two methods being based on the second but yielding a mistuning model similar to that of the rust approach. The accuracy of these three techniques in predicting the forced response of mistimed bladed disks will be assessed on simple dynamic models of the blades.
AB - The focus of the present investigation is on the estimation of the dynamic properties, i.e. masses, stiffnesses, natural frequencies, mode shapes and their statistical distributions, of nabomachine blades to be used in the accurate prediction of the forced response of mistimed bladed disks. As input to this process, it is assumed that the lowest natural frequencies of the blades alone have been experitneatally measured, for example in a broach block test. Since the number of measurements is always less than the number of unknowns, this problem is indeterminate in nature. Three distinct approaches will be investigated to resolve the shortfall of data. The first one relies on the imposition of as many constraints as needed to insure a unique solution to this identification problem. Specifically, the mode shapes and modal masses of the blades are set to their design/timed counterparts while the modal stiffnesses are varied from blade-to-blade to match the measured natural frequencies. The second approach, based on the maximum likelihood principle, yields estimates of all the structural parameters of the blades through the minimization of a specified "cost function". Finally, the third approach provides a bridge between the first two methods being based on the second but yielding a mistuning model similar to that of the rust approach. The accuracy of these three techniques in predicting the forced response of mistimed bladed disks will be assessed on simple dynamic models of the blades.
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U2 - 10.1115/99-GT-382
DO - 10.1115/99-GT-382
M3 - Conference contribution
AN - SCOPUS:84928536337
T3 - Proceedings of the ASME Turbo Expo
BT - Manufacturing Materials and Metallurgy; Ceramics; Structures and Dynamics; Controls, Diagnostics and Instrumentation; Education; IGTI Scholar Award; General
PB - American Society of Mechanical Engineers (ASME)
T2 - ASME 1999 International Gas Turbine and Aeroengine Congress and Exhibition, GT 1999
Y2 - 7 June 1999 through 10 June 1999
ER -