By Ruth Sanderson and Jane Allwright
Guided ultrasonic waves are currently used commercially to screen tens of metres of pipeline for corrosion from a single test location. In recent years, improvements have been made to guided wave inspection procedures for pipes. Methods have been developed, using both finite element analysis and experimentation, to:
- Predict the size and shape of flaws.
- Focus the sound energy on particular regions of the pipe, giving increased sensitivity.
However, the new techniques are currently designed for simple geometries only, ie straight pipes with fixed wall thickness, and can therefore be ineffective in more complex tubular structures such as those with changes in thickness, attachments or even weld cap geometry.
A literature review has been carried out, and an understanding of the state-of-the-art and the existing knowledge has been gathered. This report reviews the relevant literature on guided wave focusing.