THE PARTIAL ADMISSION OF TUNED AND MISTUNED BLADED DISKS

A numerical model for the run-up of a tuned and a mistuned bladed disc subjected to partial admission is presented. The blade is modelled by beam theory including bending-bending-torsional vibration. The disc is modelled by moderately thick plate theory. By using the extended Hamilton's principle and the Ritz method, the equations of motion are obtained. For the calculation of the forced vibrations of the bladed disc viscous model damping is included. The equations of motion are transformed by using the technique of modal approximation. The transient characteristics of tuned and mistuned bladed discs with five blades of rectangular and practical shaped cross-sectional areas are presented. The stress response spectra of the blades during partial admission are much more complicated then for the bladed disc when the number of blades is equal to the number of nozzles. An explanation of the additional local extremes of the stress is presented. © 1994 Academic Press Limited.