Low frequency ultrasonic guided waves excitated by Galfenol Rod Ultrasonic Transducer in plate inspection

Abstract

Lower frequency ultrasonic guided wave (20 kHz–200 kHz) has obvious advantages in large area plate monitoring. It enables longer propagation distances because of low attenuation and simple modes. The present study utilized a Galfenol Rod Ultrasonic Transducer (GRUT) excite low-frequency ultrasonic guided waves in plate inspection. It was verified by finite element simulation and experiment that GRUT can excite S0 mode Lamb wave, A0 mode Lamb wave and SH0 wave. A defects detection method based on A0 mode and S0 mode Lamb wave is proposed that “A0 mode Lamb wave is used for defect determination by its amplitude variation in time domain, and utilized S0 mode Lamb wave to locate the defect”. In this paper, utilize GRUT to detect a via hole with a radius of 2 cm, the experimental results show that the proposed method is convenient and fast with less signal processing, and the experimental error is 10.22 %.