Abstract:Acoustic field distribution characteristics of electromagnetic acoustic transducers (EMAT) are different. To ensure the effectiveness of detection, it is necessary to accurately measure the acoustic field distribution. For measuring the distribution of ultrasonic shear wave radiation sound field in solid metal materials, the pintype EMAT is used as a transducer. The method of measuring and reconstructing threedimensional radiation sound field based on tomography is studied. In further, a threedimensional sound field tomography measurement experiment system is established. The errors of the measurement system are analyzed, and a compensation method is proposed. During implementing experiments, the radiation sound field distribution of the toroidal coil EMAT at the excitation frequency of 35 MHz is measured. Its threedimensional radiation sound field in aluminum and low carbon steel is obtained, and its near field distance is approximately 8 mm. Experimental results show that this method can effectively provide the sound field distribution of ultrasonic shear waves at different depth sections in solid metal materials. By superimposing them, the threedimensional radiation distribution of EMAT in the solid can be achieved.