Mode Shape Description of an Aero Engine Casing Structure Using Zernike Moment Descriptors

摘要

Vibration mode shape description of an aero casing structure using Zernike moment descriptor (ZMD) is introduced in this paper. The mode shapes of the aero casing structure can be decomposed as a linear combination of a series of Zernike polynomials, with the feature of each Zernike polynomial reflecting a part of characteristic of mode shapes, based on Zernike moment transformation. Meanwhile, the reconstruction of mode shapes with Zernike moment descriptor is explored and its ability to filtering the noise contaminated in the mode shapes is studied. Simulation of the aero casing structure indicates the advantage of this method to depict the mode shapes of a symmetric structure. Results demonstrate that the Zernike moment description of the mode shapes can effectively describe the double modes in the symmetric structure and also has the ability to remove or significantly reduce the influence of noise in the mode shapes. Such feature shows great practical value for further research on the correlation, model updating and model validation of the symmetric structure's FE model