Non-axisymmetric guided wave inspection potential in tube inspection

Li, Jian; Rose, Joseph L.
May 2000
AIP Conference Proceedings;2000, Vol. 509 Issue 1, p201
Academic Journal
Much work has been reported recently on longitudinal axisymmetric wave propagation in tubular structures. Penetration power and sensitivity are improved by way of mode control via phase velocity and frequency tuning. Partial loading around a cylinder for guided wave generation and reflection from defects leads to non-axisymmetric wave propagation (flexural waves). Focus on this paper is towards the utility of non-axisymmetric as an assist device in defect detection. The dispersion curves and wave structures of flexural waves will be introduced. Based on the normal mode expansion theory, a finite size angle beam source will be discussed in terms of generation efficiency and the acoustic field distribution. Theoretical analysis shows that an infinite number of flexural modes will be generated by partial loading source for tube inspection. As different flexural modes have different phase velocities, the acoustic field distribution along the circumference varies along different distances. The impact of this non-axisymmetric field distribution on the defect testing reliability will be presented. Angle tuning of partial loading is also discussed for mode control. © 2000 American Institute of Physics.


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