Acoustic monitoring techniques for structural integrity

A general review is given of the state of the art of acoustic monitoring and this is illustrated by specific applications including the detection of high pressure fluid leaks from pipelines or storage facilities, the detection of loose parts or rattling tubes in operating plant, and acoustic emission monitoring of crack growth by 3-D source location of secondary acoustic sources caused by fretting of the crack surfaces. An active acoustic method using tomographic techniques to detect anomalous condition such as temperature 'hot spots' is also described. (orig.)