Damage Identification for Curl Tube Structure Based on Modal Flexibility Curvature

To detect the damage of curl tube structure with more effect, the finite element method (FEM) and experimental modal analysis (EMA) were employeed to generate the modal flexibility of the curl tube. The modal flexibility was used to compute the modal flexibility-curvature by using the central difference method. Different degrees and locations of damage were simulated by additional quality in the intact curl tube to verify the modal flexibility-curvature and difference generated by both FEM and EMA. The results show that the modal flexibility of curl tube should have the direction. In addition, we conclude that the flexibility curvature’s difference in x and y plane can not be used for damage identification. But using the flexibility curvature’s difference of the z direction in the vertical plane, we can not only identified the multiple damage location, but also to analized degree for the extent of injury to the same location .