Study on large lift-off electromagnetic thermography detection method for rail
In practical electromagnetic thermography for rail inspection,due to factors such as vibration and uneven track surfaces,it is necessary to position the excitation coil at a greater lift-off distance to ensure the safety and reliability of the rail inspection process.However,due to the lift-off effect,the lift-off distance of most electromagnetic thermography excitation coils is limited to within 10 mm,resulting in a lack of research on electromagnetic thermography methods for large lift-off rail inspection.Therefore,this paper first analyzes the limitations of existing electromagnetic thermography inspections related to lift-off distance and designs a serpentine-shaped magnetic induction coil suitable for large lift-off conditions.Subsequently,through theoretical,simulation,and experimental analysis,it determines an appropriate liftoff distance and proposes a large lift-off rail electromagnetic thermography inspection method based on the aforementioned excitation coil.Under conditions of a 30 mm lift-off distance and a detection speed of 1 m/s,this method was applied to the actual inspection of six different-sized rail defects.The results indicate that the large lift-off rail electromagnetic thermography inspection method proposed in this paper is capable of detecting all six types of defects,and these defects are prominently displayed in the thermal images.
large lift-offelectromagnetic thermography detectionserpentine-shaped magnetic induction coilrail inspection
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维普
