Method and apparatus for monitoring wall thinning of a pipe using magnetostrictive transducers and variation of dispersion characteristics of broadband multimode shear horizontal (SH) waves

A method for monitoring wall thinning using magnetostrictive transducers and a variation of dispersion characteristics of broadband multimode shear horizontal (SH) waves in a wall-thinning monitoring apparatus, which includes a transmitting transducer which is installed outside of a pipe and generates shear horizontal (SH) waves traveling along the pipe, a receiving transducer which is spaced apart from the transmitting transducer and measures shear horizontal (SH) waves traveling along the pipe, and a controller for monitoring wall thinning of the pipe by exciting and measuring signals of the transmitting and receiving transducers, wherein each of the transmitting and receiving transducers includes a thin plate-shaped patch, two magnets for applying a bias magnetic field passing along the patch, and a coil arranged between the two magnets, the method comprising:

• generating, by the transmitting transducer, multimode SH waves, and propagating the SH waves in a direction of a pipe axis;
• and
• receiving, by the receiving transducer, the SH waves propagated along the pipe, and monitoring whether a variation of mode's dispersion characteristics occurs in the measured SH waves.