EMAT transducers were developed for use in dry and non-contact inspection, as an alternative to using piezoelectric transducers. While in the piezoelectric transducer the sound is generated in the own transducer and transmitted to the part through a coupling, the EMAT induces ultrasonic waves in the material to be inspected by two interacting magnetic fields.
In this work the ultrasonic beam generated by conventional and Phased Array EMAT transducers is studied. Regarding the conventional transducers, the influence of the geometry of the coil is analysed. Concerning the EMAT Phased-Array, the configuration of the transducers is pointed out and also the improvements that it offers over conventional transducers. The simulations were performed using CIVA a specific ultrasound software.
The capabilities of the EMAT technology have been demonstrated in the laboratory with the development of one inspection system able to detect cracks and another for measuring residual stress.
The results show that the simulation tools are very useful for the design of EMAT transducers due to their capacity to analyse a huge key variables in their operation.
