Abstract: Provided are an apparatus and a method for measuring a nonlinearity parameter using laser, and more particularly, an apparatus and a method for measuring a nonlinearity parameter using laser for computing the nonlinearity parameter by irradiating laser of a toneburst signal on a surface of a sample by non-contact type laser so as to excite the sample, irradiating measurement laser beam on the surface of the sample so as to receive displacement information occurring on the surface of the sample over time, measuring the displacement in an interferometer principle, and performing a bandpass filtering for the measured signal so as to measure amplitude A1 of a component of a fundamental frequency and amplitude A2 of a component of a secondary harmonic wave.

Abstract: Disclosed are an apparatus for detecting pipe wall thinning, which measures a natural frequency of a pipe and determines a level of the pipe wall thinning, and a method thereof. The apparatus for detecting the pipe wall thinning includes a hitting member 10 for hitting the pipe T, a vibration measurement sensor 20 which measures a vibration signal generated when the pipe T is hit with the hitting member 10, and a control part 30 which compares the natural frequency calculated from the vibration signal measured from the vibration measurement sensor 20 with a natural frequency generated from a normal pipe in which wall thinning does not occur, and determines the level of the wall thinning of the pipe T.

Abstract: Provided are an apparatus and a method for measuring a nonlinearity parameter using laser, and more particularly, an apparatus and a method for measuring a nonlinearity parameter using laser for computing the nonlinearity parameter by irradiating laser of a toneburst signal on a surface of a sample by non-contact type laser so as to excite the sample, irradiating measurement laser beam on the surface of the sample so as to receive displacement information occurring on the surface of the sample over time, measuring the displacement in an interferometer principle, and performing a bandpass filtering for the measured signal so as to measure amplitude A1 of a component of a fundamental frequency and amplitude A2 of a component of a secondary harmonic wave.

Abstract: Disclosed are an apparatus for detecting pipe wall thinning, which measures a natural frequency of a pipe and determines a level of the pipe wall thinning, and a method thereof. The apparatus for detecting the pipe wall thinning includes a hitting member 10 for hitting the pipe T, a vibration measurement sensor 20 which measures a vibration signal generated when the pipe T is hit with the hitting member 10, and a control part 30 which compares the natural frequency calculated from the vibration signal measured from the vibration measurement sensor 20 with a natural frequency generated from a normal pipe in which wall thinning does not occur, and determines the level of the wall thinning of the pipe T.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.