| ABSTRACT: | GUIDED WAVE NON-CONTACT ULTRASONIC FOR NDE
B. Boro Djordjevic1, D. Cerniglia2, and C. Cosenza2
1Johns Hopkins University, Baltimore, MD USA; 2Tecnogamma SPA, Palermo, Italy
The emerging technology of non-contact ultrasonic now in development, enables rapid testing of structures
using ultrasonic tests that are not possible via conventional contact transducers. This paper reports on
application of guided waves laser ultrasonic and air/gas coupled ultrasonic measurements that are performed
remotely, do not require direct access to test area, do not need traditional ultrasonic coupling and do not
have traditional C-scan fixture requirements. A Lamb wave generated in the plates, or surface acoustical
waves can reach and inspect regions of structure not accessible using conventional ultrasonic transducers.
Analysis of recorded signals from a single test allows assessments of the material properties or material
damage condition. The experimental results on aircraft aluminum structures, adhesively bonded components
and composite materials demonstrate that such testing techniques can perform detail assessment of structural
integrity using inspection access from only one side of the structure. Because there is no requirement for a
mechanical coupling medium to transmit the ultrasound or transducer roster scanning positioning such as in
the ultrasonic C-scan tests, the structure can be inspected remotely and at higher test speed then by
conventional contact or scanning ultrasonic methods. These new, non-contact ultrasonic testing methods,
have potential for in-situ evaluation of advanced structures such as aircraft components for presence of
corrosion, cracks and fatigue damage. Experimental tests show feasibility of the technology to support
maintenance inspections during the service life of the aircraft.
|