Research Note: Effect of Mistuning on Forced Vibration of Blades with Mechanical Coupling

Abstract

It is shown that when there is mechanical coupling between blades through their root fixings, then the maximum factor by which the vibration amplitude can increase due to mistuning is given approximately by 1/2[1 + √( N/2)], where N is the number of blades in the row. This contrasts with the factor of 1/2(1 + √ N), derived in an earlier paper, due to more general aerodynamic coupling. The cases when adjacent blades are excited either in phase or in antiphase are exceptional, and in these cases the earlier analysis applies. These factors can be closely approached when just one blade is mistuned.