Investigations Into Theory And Method Of A Rotating Electromagnetic Field Non-destructive Evaluation Technique

This work is based on China postdoctoral science foundation project(2013 M540568)"tube defects rotating magnetic field detection method research",in view of the existing bottleneck of electromagnetic defect detection technology any direction,introducing the theory of rotating magnetic field,with the help of the transient simulation technique based on the finite element model for research on the effects of detection performance,and finish the design of rotating electromagnetic field detection system development and testing.This paper based on the basic equation of electromagnetic field and the defect model,derived from the basic equation of electromagnetic theory from the Angle of analyzing the principle of produce a rotating magnetic field and magnetic field disturbance detection methods,and by using the finite element analysis and the simulation method,based on a rotating magnetic field detection and defects of pipeline,and is designed to motivate the rotating magnetic field to probe model and according to the form of a rotating magnetic field generated by choosing the optimal incentive method.With the help of engineering simulation software put forward relevant characteristics of the signal accurately,for signal analysis and provides the reference for the identification of defect features.First of all,explores the tested material affect the performance of detection.Secondly,based on the defective and no defect of related signal extracted and contrast,the study of the characteristics of defect analysis of the influence of the spatial distribution of magnetic field,and on this basis to the accurate positioning of flaw was carried out,and the defects of relevant parameters are obtained.Finally,explores the probe of the related parameters in the excitation winding of a rotating magnetic field on the effects of the test consists of a rotating magnetic field pole logarithmic and distribution form,the axial and radial or axial size.At the same time,we to signal pick-up device and the distance between the wall,the optimization analysis.According to the above method,simulation research results and related theory design based on the metal surface of a rotating magnetic field detection system,and the driver circuit,detecting sensor and signal acquisition of main parts are the hardware design and complete the installation of the test.