A Numerical Method for the Prediction of Bladed Disk Forced Response

A numerical method has been developed to predict the forced response of bladed disks due to a wake excitation from upstream blade rows. The structure is modeled by a three-dimensional finite element mesh of a bladed disk segment. Using cyclic symmetry, this model provides a modal base for the rotating structure. The aerodynamic damping of the vibratory modes and the excitation pressures on the blades due to the propagation of upstream flow defects are computed separately using the same three-dimensional unsteady Euler analysis software. A modal response solution of the aeromechanical system is then performed. This analytical methodology has been used to study the forced response of an experimental high pressure compressor blisk. The results are analyzed and compared with actual rig tests.