Abstract
Multi-packet blade systems consist of several blades which are attached to a disk and connected through shrouds. The blades of a multi-packet blade system are mostly assumed to be identical. However, there always exists small, random mistuning among the blades due to manufacturing tolerance, in-operation wear, and environmental changes. Such mistuning may cause significant increase in the forced vibration responses of some blades in the multi-packet blade system. Critical fatigue problems often occur in mistuned system since the forced vibration response of a mistuned system is often significantly larger than that of a perfectly tuned system. Therefore, it is very important to predict the maximum blade response. In this study, blades are idealized as cantilever beams and the flexibilities of the disc and the shrouds are idealized as discrete springs. Equations of motion are derived by using the hybrid deformation variable method. To verify the vibration localization with random mistuning, transient analysis are carried out for the multi-packet blade system excited by multiple nozzle jet forces.
