The Investigation On Structure Parameter Identification Of The Key Parts Based On Eddy Current Testing

Structural parameter identification can be used for condition monitoring, structure performance evaluation, damage identification in engineering field. It also plays an important role in ensuring the safety and normal work of the active structure. Over the past few decades, the researchers had done a large amount of work for structural parameter identification based on the vibration theory, which effectively promoted the development of the structural parameter identification.Based on the summary of the existing research results, the two key parts are investigated in the paper. The main works are summarized as follows:(1) In terms of the modal analysis and harmonious response analysis theory, changes of modal parameters are studied under different geometric feature size of parts by means of finite element analysis software. The change relationship and its reasons are discussed. The conclusion that how the modal frequency is changing with the geometric parameters of two parts is summarized.(2) Structural parameter identification hardware platform is set up, including specimen fixture, excitation system, measuring system. Data acquisition card that can be used under the environment of virtual instrument and non-contact sensors that can obtain vibration signal based on Eddy Current Testing are selected. Specimens and fixture are processed.(3) By means of the transfer function matrix and Chebyshev orthogonal polynomial, orthogonal polynomial fitting method and the peak search to the whole recognition algorithm have been carried out with deep discussion, and implemented in Labview. Furthermore, the software development of structural parameter identification system is completed, including implementation of data acquisition program, the sampling data of the weighted average and window filtering, the realization of the man-machine interface.(4) Four specimens are used as experimental object to make experimental parameter identification and results validation with the established software and hardware platform,reasons of experiment error are analyzed. In addition, the ways of acquisition parameter setting and modal order confirmation are discussed. The way to plot stability diagram is investigated as well. The conclusion is that using experimental platform and recognition algorithm given in this thesis can effectively identify structural parameters of the tested parts.