Abstract
It is required to evaluate nondestructively depth of surface-breaking cracks in structures. In this paper, the self-calibrating technique by laser-based ultrasound is used to measure the depth of surface-breaking crack. Optical generation of ultrasound produce well defined pulse with a reliable frequency content. They are broad banded and are suitable for the measuring of attenuation and scattering over a wide frequency range. The self-calibrated surface signal transmission data shows a good sensitivity as practical tool for assessment of surface-breaking crack depth. It is suggested that the relationship between the signal transmission and crack depth can be used to predict the surface-breaking crack depths in structures.
