Due to geometric complexity and flexural mode conversion in pipe elbow regions, guided wave detection of a discontinuity either in the elbow region or beyond is usually difficult, especially when only partial loading around the circumference of the pipe is possible. The signals from the discontinuities are either low in energy or immersed into the weld echoes in the elbow region. A new flexural mode tuning technique to find discontinuities in the elbow region by amplifying the discontinuity signal and improving the subsequent signal to noise ratio is introduced in this paper. Flexural mode tuning can be accomplished by a staggered spacing of angle beam transducers around the pipe or by circumferential time delay profiles applied to the multielement angle beam transducers or segmented comb elements mounted in the plane around the circumference of the pipe. Experimental results indicate the potential of this method for finding the discontinuities both at the outside and the inside region of the elbow.
|Original language||English (US)|
|Number of pages||4|
|Specialist publication||Materials Evaluation|
|State||Published - May 2001|
All Science Journal Classification (ASJC) codes
- Materials Science (miscellaneous)