Study On The Forward Model Of The Eddy Current Testing And The Communication In The Testing System

Eddy current testing (ECT) is one of the most used methods of Nondestructive testing. Eddy current testing measurements are frequently applied to the nondestructive testing of different types of conducting materials. It cost low, and can be very quickly carried out. This paper study on some problems in eddy current testing, and the main works are listed as follows:1. Presented an analytical model which describes the impedance change when an air-cored coil sensor is placed next to a conducting plate. Analysis of the model reveals that the phase of the impedance signature is lift-off independent. It is helpful to distinguish the change of lift-off from the thickness change of the plate. Analysis of the lift-off effect of phase spectra for eddy current probe is a new way which can be used in practical application. This finding is verified by numerical simulations and experiments.2. Used the Maxwell 3d simulated the model of the conducting materials which have different flaws, researched the distribution of the magnetic field in the probe and the conducting plate. Based on the result of simulation, a method was proposed that how to located the sensor in the probe, so that we can distinguish defect from the plate well. For this purpose, which parameter of the magnetic field is also analyzed.3. Devised a communication protocol used in the eddy current testing system. Use the same format of data package to send out different kinds of command data, by identifying the special byte, it could distinguish the different command data, a database also was designed, all this was realized using the graphical language, and gets a good performance in practical application.