TWI Industrial Member Report Summary 928/2009
By R Sanderson
Guided waves are an exciting and relatively new non-destructive testing technique used for screening pipes for corrosion. The big advantage is the ability to inspect the full volume of tens of metres of pipeline from a single test location in a matter of seconds.
The technique is already used commercially as a screening tool. TWI has researched and developed guided wave technology from the outset. Teletest®, sold by Plant Integrity Ltd (a subsidiary company of TWI) is one example of the type of equipment that is now available. The technique works well in straight lengths of pipe and can be used to provide information about corrosion severity.
The technique would be significantly improved if it were able to give more quantitative information about flaw size and had the ability to reliably inspect beyond pipe bends. Novel flaw sizing techniques have been already developed by TWI in the Core Research Programme (Sanderson et al, 2008) and full validation of this for a range of pipe sizes is now the subject of a Group Sponsored Project.
In this project, the effects of pipe bends on guided waves have been studied using established modelling methodology that has been successfully validated a number of times (Sanderson, 2003, 2007a and b, Sanderson et al, 2008). The aim of the work was to use the insight modelling provides to quantify and gain an understanding of the behaviour of guided wave propagation in and beyond pipe bends and to therefore devise methods for overcoming the effects of bends. Experimental confirmation of these techniques is intended to be the subject of subsequent project work.
- Use modelling to quantify the effects of pipe bends on guided waves for a range of pipe bend angles.
- Develop signal reconstruction techniques for overcoming the effects of pipe bends on the propagation of guided waves.