[1B4] Design of orthogonal directional shear horizontal electromagnetic acoustic transducer
A Gautam¹,², C Yin¹ and B Bhattacharya²
¹National Yang Ming Chiao Tung University, Taiwan
²Indian Institute of Technology Kanpur, India
This research proposed an electromagnetic acoustic transducer (EMAT) for generating and receiving orthogonal directional shear horizontal (ODSH) guided waves in a metal plate-like structure. The proposed EMAT generates the fundamental shear horizontal (SH) wave mode in the horizontal and vertical direction in the plane of the test sample. The ODSH-EMAT combines a new chevron-like coil design that generates an eddy current effect in the skin depth of the plate surface and a periodic permanent magnet (PPM) that applies a static magnetic field vertically with a periodicity equal to its wavelength. The direction of the resultant Lorentz force acting on the test surface-controlled PPM underneath a specific chevron angle of the coil wire is presented. The constructive interference of propagated waves has been developed in the orthogonal directions, enhancing the ultrasonic signals and improving the signal-to-noise ratio. A finite element simulation has been carried out with a thin aluminium plate, keeping the proposed EMAT at the centre of the sample. Furthermore, the simulation results show good agreement with the proposed design.
Keywords: EMAT, SH guided wave, PPM.
Keywords: EMAT, SH guided wave, PPM.
