Feasibility of Using Ultrasonic Guided Waves for Under Water Pipe Inspection

Abstract

Non destructive testing techniques are preferred techniques for damage detection in this new era of development. Health monitoring of materials and structures during its service life using NDT is an emerging field. Ultrasonic testing is a promising candidate of NDT. It uses high frequency sound waves which are injected into the material to detect the defects and discontinuities in the material. This report presents the study of feasibility of using pulse transmission (PT) method with ultrasonic guided waves to detect the simulated defects in immersed pipes. Mild steel pipe specimens in immersed condition have been used in the study. Presence of water in immersed state has been exploited as a means to couple the transducer with the pipe. A conventional ultrasonic system consisting of pulser/receiver and data acquisition system has been used. Attenuation of the transmitted signal has been used as an indicator to measure the presence and extent of damage. Actual corrosion has been induced in the pipes using impressed anodic current technique. Ultrasonic signatures recorded at different stages of corrosion have been found to relate with extent of material loss due to corrosion