Recent advances in guided wave NDE

Guided wave NDE applications are becoming more popular each day, primarily because of the many recent developments on understanding their complexity and potential in defect detection, classification, and sizing analysis. Mode selection can be based on wave structures that can achieve improved sensitivity to certain defects as well as superior penetration power for immersed or coated structures. Utility dispersion curves are available to study wave structure variations along a specific mode. The source influence effect and its influence on the phase velocity spectrum is now understood, allowing either multiple modes to propagate or a high energy isolated mode. Boundary element techniques are now being used to calculate mode conversion reflection and transmission factors for a particular incident mode and frequency onto a specific defect. Resonance matching procedures are also being introduced to allow efficient transfer of energy across a joint or geometrical structure variation. Tube inspection in the power generating field for heat exchangers and steam generator tubing will be discussed. Several applications will also be presented for fuselage, lap splice joint, tear strap, and composite patch repair in aging aircraft inspection. Initial work efforts on flaw classification will be presented. Finally, applications in manufacturing will be introduced focusing on a powder metal injection molding in situ guided wave measurement system.