A Type of EMAT for Simultaneous Detection of Two Components of Rayleigh Wave
Yutang Wu, Yunxin Wu, Tao Zhang
Abstract
A new design of electromagnetic acoustic transducer (EMAT) is proposed for simultaneous measurement of in-plane and out of plane displacement components of Rayleigh wave. The EMAT consists of nine magnets and two meander-line-coils (MLCs). There almost only exists vertical or horizontal magnetic field at some specific positions in the magnetic field generated by the EMAT. By adjusting the interval between adjacent conductors and the position of conductors, the conductors in one coil are almost only in the vertical magnetic field and the conductors in the other coil are almost only in the horizontal magnetic field. Therefore, the two coils in this EMAT will almost only react with in-plane and out of plane displacements respectively. With this EMAT, repeated positioning or large area is not required during the measurement process. In addition, this EMAT can measure the two displacement components simultaneously without calculation. Meanwhile, this EMAT is much more sensitive to the ultrasonic waves for the magnetic field generated by the EMAT is enhanced. The measurement results of this EMAT are consistent with those of conventional EMATs, which indicates that the measurement results are accurate and reliable.