Damage location by ultrasonic Lamb waves and piezoelectric rosettes

摘要

An approach based on Macro-Fiber Composite (MFC) transducer rosettes and ultrasonic guided waves is proposed for damage location in plate-like structures. By using the directivity behaviour of the three MFC sensors in each rosette, the direction of an incoming wave generated by scattering from damage can be estimated without knowledge of the wave velocity in monitored structures. Two rosettes suffice to identify the location of a scatterer in a planar structure. The technique does not have any drawbacks of time-of-flight triangulation that requires information on wave velocity and thus complicates damage location when testing anisotropic materials, tapered sections, or any structure under temperature fluctuations. The effectiveness of the piezoelectric rosette method is tested experimentally using an aluminium plate with a simulated damage subjected to temperature variation.