Nodal diameter vibration identification of coated blisk under traveling wave excitation

It is seen that blisk will be in a nodal diameter vibration state under the engine order excitation, which can be simulated by traveling wave excitation. The nodal diameters rotate on the blisk and it is necessary to identify the specific form of the nodal diameter vibration. Here, based on the determination of nodal diameter vibration parameters, a novel identification method of the nodal diameter vibration was proposed through the experimental test. Specifically, a traveling wave excitation system was built using the LabVIEW control software and noncontact magnetic exciters. Based on the description of resonant state of blisk, the identification principle formulas of the nodal diameter vibration were derived and the identification procedure was given. Taking uncoated and coated blisks as the research objects, the identification method was demonstrated. The identification results showed that the shape, direction, speed, and period of nodal diameter vibration were successfully obtained by the proposed method. In addition, it was found that coatings have a damping effect on blisk. Because of the coating introduction, the blisk vibration response was reduced, the rotation speed of nodal diameter was slowed down, and the rotation period of nodal diameter was increased.