Review of Crack Depth Measurement by Ultrasonics
Research concerning bulk and surface wave methods for the measurement of the depth of surface-breaking cracks will be reviewed. This review will examine techniques for measuring crack depths which are based on the scattered pulse amplitude, time-of-flight methods, and ultrasonic spectroscopic analysis. Measurement of the transit time of bulk waves appears most likely to provide simple and reliable depth measurement in the near future. Promising directions for future research will be discussed.