Seoul National University

Soon Woo Han

Yoon Young Kim

Seung Hyun Cho

Chan Il Park

Chan Park, Ii

Provided is an electromagnetic acoustic transducer including a main body formed of a non-metal material and having a hollow portion, a magnetic field generation portion generating two magnetic fields parallel to a lengthwise direction of the rod member and in opposite directions to each other, at both sides of the rod member that is inserted in the hollow portion of the main body, and a coil wound around an outer circumferential surface of the main body.

Electromagnetic acoustic transducer for generating and measuring bending vibration in rod member using anti-symmetric magnetic field structure

Provided is a method and apparatus for generating and sensing torsional vibrations using magnetostriction, in order to perform modal testing on a bar, a pipe, a shaft, a beam, or the like. The apparatus includes a torsional vibration generating part transmitting torsional vibrations to a test part having an arbitrary cross-section and a predetermined length, and a torsional vibration sensing part sensing the torsional vibrations generated from the torsional vibration generating part. The torsional vibration generating part and/or the torsional vibration sensing part includes a magnetostrictive body attached around the test part and made of a magnetostriction material, a first magnetic field forming part forming a magnetic field around the test part in a circumferential direction of the magnetostrictive body, and a second magnetic field forming part forming a magnetic field to the magnetostrictive body in a direction substantially perpendicular to the direction of the magnetic field formed by the first magnetic field forming part and in parallel with a longitudinal direction of the test part.

Apparatus and method for generating and sensing torsional vibrations using magnetostriction

A method and an apparatus for structural diagnosis, which generates torsional waves upon a shaft, beam or pipe having arbitrary cross-sections, such as a circular cross-section, and senses existence or location of the cracks through analyzing reflected waves are disclosed. A magnetostrictive transducer comprises a plurality of ferromagnetic strips attached around a circumference of a member having a arbitrary cross-section with a fixed inclination; a first housing disposed to surround the ferromagnetic strips, the first housing being made of insulating material; and a coil would around the first housing. The magnetostrictive transducer can generate torsional waves upon a member when a current is supplied to the coil, and can measure reflected torsional waves.

Transducer for generating and measuring torsional waves, and apparatus and method for structural diagnosis using the same

An apparatus for generating and measuring bending vibration in a pipe buried underground or a pipe covered by insulating materials is disclosed. There is provided an apparatus for generating and measuring bending vibration in a non-ferromagnetic pipe without physical contact, comprising: a ferromagnetic strip adhered on a surface of the pipe; a coil wound around the surface of the pipe; two magnets for generating bias magnetic field, applied to the strip and parallel to the strip; a power source for supplying an electric current to the coil; and a measuring unit for measuring variation of voltage across the coil, the variation of the voltage being generated due to a strain according to inverse magnetostrictive effect, the strain being generated due to bending vibration, the bending vibration being generated due to deformation of the strip, the deformation being induced according to magnetostrictive effect as the power source supplies the electric current to the coil.

Growing community of inventors

Seoul, South Korea

Soon Woo Han