Magnetic Flux Leakage And Electromagnetic Acoustic Combined Testing System For Tank Floor Plate

As an efficient nondestructive testing method,magnetic flux leakage detection method is widely used in tank floor plate inspection.Electromagnetic ultrasound is a non-contact thickness measurement method,which avoids grinding the specimen surface.Based on this,the dissertation puts forward a way of using superposition of magnetic field to enhance electromagnetic thickness signal based on magnetic flux leakage and electromagnetic ultrasonic testing principle,which evaluates the thickness loss of the specimen while detecting the defect.The dissertation completes the combined testing sensor parameter design,develops combined testing system and tests performance.Firstly,based on the analysis of the principle of magnetic flux leakage detection and electromagnetic ultrasonic shear wave thickness measurement,the principle of magnetic flux leakage and electromagnetic ultrasonic combined testing is proposed.The composite test platform is built to verify the principle of combined testing.The experimental results show that the superposition magnetization method can be applied to magnetic flux leakage detection and electromagnetic ultrasonic thickness measurement,and the magnetic flux leakage detection and electromagnetic ultrasonic thickness measurement do not interfere with each other.Secondly,the composite sensor parameter design is completed.Based on the orthogonal experimental principle,the finite element experiment plan is designed,and the finite element model of the combined testing method based on the electromagnetic field,the force field and the sound field direct coupling method is established.Using the composite test platform,the coil parameters are designed by experiment.Finally,the dissertation develops combined testing system and tests the combined testing performance.A combined testing probe for tank floor plate is developed.The mechanical structure of the scanner is designed,and the combined testing software is developed and assembled into a tank floor plate composite inspection system.The dissertation builds the experimental platform to test the combined testing performance.The experimental results show that the combined testing system can detect a diameter of 1.6 mm hole through the test plate whose thickness is 6mm,and the thickness of the test plate can be evaluated while the defect is detected.