Abstract This paper is concerned with transmit-receive mechanism of the electromagnetic ultrasonic tran sducer (EMAT) for the guided wave. First, the three-dimensional guided wave propagation simulator is de veloped. This simulator calculates the particle velocity from the force which are excited by EMATs with FDTD method. Second, configuration of EMATs is designed based on our study of the excitation mechanism of an EMAT, in order to transmit and receive the longitudinal mode (L-mode) or the torsional mod...
英字タイトル:
Analysis of transmit-receive mechanism of EMAT for the guided wave

This paper is concerned with development of guided wave simulator on piping diagnostic system. First, a mathematical model of inspe ction procedures is described by a set of dynamical linear elastic equations in three spatial dimensions. Secondly, the numerical s cheme of the inspection model is given by using FDTD method. Finally, some numerical experiments are shown in order to assure the ap plicability of the proposed scheme to piping test. ...
英字タイトル:
Development of Guided Wave Simulator using FDTD method and its Application toNondestructive Testing

The aim of this work presented here is to demonstrate the method for estimating the pipe wall thinning configuration: location, width, depth of pipe wall thinning in straight pipe based on velocity dispersions of longitudinal guided wave. First, group velocity dispersion curve is derived from frequency equation. Second, group velocity of longitudinal guided wave is analyzed using guided wave simulator for pipe with notch-shaped and ellipse-shaped circular pipe wall thinning. Finally, method for estimat...
英字タイトル:
Estimation of the Pipe Wall Thinning Configuration Based on Velocity Dispersions of Longitudinal Guided Wave

The aim of this work presented here is to demonstrate the way to identify the shape of pipe-wall-thinning in straight pipe. First, the database is developed to obtain approximate solution of waves reflected from pipe-wall-thinning with three-dimensional guided wave simulator and proper orthogonal decomposition (POD). In particular, we show that the database can be used to efficiently approximate the solutions to the guided wave propagation problem. Second, the inverse problem procedure is introduced to...
英字タイトル:
3-Dimensional Shape Identification of Pipe-Wall-Tinning With Ultrasonic Guided Wave

Motivated by growing demand for quantitative nondestructive evaluation of pipe wall thinning, the aim of this paper is to develop a simulator for gu ided wave analysis. First, an inspection system can be represented by a linear elastic system in cylindrical coordinates. Secondly a dynamical numer ical scheme for wave propagation on a pipe wall is proposed based on Fourier-Galerkin approach. Finally, the effectiveness and validity of the propo sed method are shown in computational experiments. ...
英字タイトル:
Development of a Guided Wave Simulator and its Application to Monitoring of Pipe Wall Thinning

The aim of this work presented here is to analyze the mechanism of ultrasonic test signals in magnetic materials using electromagnetic acoustic transducer (EMAT). The coupling mechanism for EMAT between the electromagnetic fields and the applied excitation of ultrasonic wave are investigated. First, a nonlinear magnetic model in two dimensions is presented for the coupling mechanism. Secondly, the coupling mechanisms in ferromagnetic materials are studied analytically and numerically. Finally, the nume...
英字タイトル:
Analysis of Ultrasonic Source in Magnetic Materials Using Electromagnetic Acoustic Transducer

Industry development activities on applied laser research held at Fukui branch of Japan Atomic Energy Agency are reported. Industry development is inevitable in long-term vision and strategy for developing maintenance technology and establishing decommissioning technology. Fukui branch of JAEA has organized public seminar offering businesses to promote these activities and technology exchange for years. Here some examples offered in the current seminar are introduced concerning with laser technology. Fin...
英字タイトル:
Industry Development Activities and Applied Laser Research Activities at Fukui Branch of Japan Atomic Energy Agency

The aim of this work presented here is to investigate the applicability of the guided wave testing to detect and evaluate the quality of laser beam butt welding line. First, four test pipes were prepared. All of the pipes were laser beam butt welded from inside of the pipe using laser torch. Two pipes of them were high-quality welded, the others were low-quality. Two different pipe-wall-thicknesses were in each quality. Secondly, Laser beam butt welding line detection and the quality evaluation experim...
英字タイトル:
EMAT-Guided Wave Approach for Detecting and Quality Evaluation of the Laser Beam Butt Welding Line on the Inner Surface of the Steel Pipe