Noncontact and rapid measurement of elastic properties of metals with a dual-mode bulk-wave EMAT

The elastic mechanical behaviour of materials is very important to the design and service safety evaluation of mechanical load components. In order to accurately measure the elastic mechanical behaviour of metal structures with a non-destructive testing way, a dual-mode bulk-wave electromagnetic acoustic transducer (EMAT) is developed for both ultrasonic longitudinal wave and shear wave measurement. The elastic modulus and Poisson’s ratio of metals are directly obtained with the velocities of the longitudinal and shear waves. In order to improve the efficiency of electromagnetic acoustic transducer, the electromagnetic acoustic parameters were characterised and optimised by numerical simulation. The results show that the developed dual-mode EMAT can successfully excite and receive longitudinal and shear waves, and the elastic modulus and Poisson’s ratio of different materials (copper, aluminium and steel) obtained through experiments using the developed dual-mode EMAT are very close to the reference values.