Development Of The Tank Floor Thickness Measurement System Based On The Electromagnetic Ultrasonic Transverse Wave Transducer

As a non-contact non-destructive testing method,electromagnetic ultrasonic thickness measurement has low requirements on the surface cleaning of the object to be inspected,and has broad application prospects in the detection of the tank bottom plate.Based on the finite element simulation analysis of the characteristics of electromagnetic ultrasonic shear wave thickness sensor,this dissertation develops a four-channel electromagnetic ultrasonic transverse wave thickness measurement system for the tank bottom plate and completes the performance test.Firstly,the influence of the size of the closed magnetic circuit magnetizer structure on the performance of the magnetizer in the electromagnetic ultrasonic transverse wave sensor is analyzed by static magnetic field finite element simulation.The static magnetic field simulation results of the closed magnetic circuit and the open magnetic circuit show that,for the same size,for the electromagnetic ultrasonic shear wave excitation,the open magnetic circuit has higher magnetization efficiency than the closed magnetic circuit.Based on the normalized sequential coupled electromagnetic ultrasonic shear wave simulation method,the feasibility of the proposed method is verified by experiments.The method is used to verify the similarity of the echo signals of the two magnetic path excitation ultrasonic shear waves.Based on the integrated design idea,the design of four-channel open magnetic circuit electromagnetic ultrasonic probe is carried out.Secondly,complete the electromagnetic ultrasonic thickness scanner and the structure design of the detection probe.Dynamic simulation of the scanner to complete the motor selection.Combined with static simulation,the strength and stability of the key structure of the scanner are checked,and the lightweight design of the scanner is realized by the topology optimization method.Finally,on the basis of the above research,the electromagnetic ultrasonic wave transverse thickness measurement system of the tank bottom plate was developed and the test platform was built.The test results show that for the defect-free aluminum alloy plate and stainless steel plate test piece,the four channels of the scanner can accurately measure the thickness of the plate,and the thickness measurement accuracy meets the requirements;for the steel plate test piece,the wall thickness is reduced by 60%.The spherical blind hole can be accurately identified,and the measured thickness value is basically consistent with the average thickness conversion result of the defect.