3-D FEM Simulation and Analysis on the Best Range of Lift-off Values in MFL Testing

Abstract In order to avoid oil and gas leakage or explosion due to corrosion defects or cracks in pipelines or tanks, it is very important to test the pipelines and tanks in service. In this study, a three-dimensional (3-D) finite element method (FEM) simulation model of the magnetic flux leakage (MFL) field was established. The MFL signals were simulated and analyzed in connection with different defects and lift-off values, considering the condition of the mechanical vibration and electromagnetic noise. The best range of lift-off values can be determined from the results of simulation and analysis. This is a very effective method for improving measurement accuracy in practical MFL testing. It also provides a reference for the optimization of testing mechanical structures in the MFL technique.