Simulation And Analysis Of The Remote Filed Eddy Current Based On Finite Element Method

The remote filed eddy current (RFEC) techniques will become more and more important as a tool of the pipes' daily check and maintenance in power and chemical industry. In this article,the finite element tool is used to simulate and analysis two-dimension axial-symmetry model and three-dimension model especially for fine defect, then methods of improving on probe are investigated systematically. Firstly, the basic character of the remote filed eddy current is simulated and analyzed in case of two-dimension axial symmetry which approves the existence of remote filed eddy current phenomenon; the full circumferential defect model is investigated to approve the feasibility of using the RFEC techniques to detect the position and depth of defect; the pit corrosion,circumferential and axial crack models are simulated, and the defect character based on voltage plane polar plot and the changes of phase and amplitude are analyzed to supply the standard for defect reconfiguration. Secondly, methods of improving on probe are investigated in detail: using the electromagnetic shielding effect to decay the direct-coupled magnetic field and using the dual probe to control the energy flow, so as to make the probe to be shorter; designing 3-D pick-up coil array to increase detection sensitivity. At last, experiment system is set up to verify the simulation result and the comparing result shows simulation result agrees with experiment result. In general, the simulation result can be used to supervise experiment investigation.