Abstract
In the rapidly expanding composite industry, novel inspection methods have been developed in recent years. Particularly promising for air-coupled testing are cellular polypropylene transducers which offer better impedance matching to air than piezoelectric transducers. Furthermore, broadband transmitters (laser-induced ultrasound and thermoacoustic emitters) and receivers (optical microphones) have opened a completely new chapter for advanced contact-free ultrasound inspection. X-ray dark-field radiography offers a different approach to detect porosity and microcracks, employing small angle X-ray scattering. These innovative ultrasonic and radiographic alternatives were evaluated in comparison with well-established inspection techniques. We applied thirteen different non-destructive methods to inspect the same specimen (a carbon fiber-reinforced polymer laminate with induced impact damage): air-coupled ultrasound testing (using piezoelectric transducers, broadband optical microphones, cellular polypropylene transducers, and a thermoacoustic emitter), laser-induced ultrasound testing, ultrasonic immersion testing, phased array ultrasonic testing, optically excited lock-in thermography, and X-ray radiography (projectional absorption and dark-field, tomosynthesis, and micro-computed tomography). The inspection methods were qualitatively characterized by comparing the scan results. The conclusions are advantageous for a decision on the optimal method for certain testing constraints.
Highlights
Reconstructed images obtained by inspection methods deliver only a more or less accurate approximation of the reality
We suggest optimal inspection methods for specific applications
If the inspection process is to be automated and performed quickly, aircoupled ultrasound (ACU) is the most elegant solution for the specimens with suitable geometry, especially if they are sensitive to liquid couplants
Summary
Reconstructed images obtained by inspection methods deliver only a more or less accurate approximation of the reality. Each non-destructive testing method has its own characteristic footprint, which alters information about the observed feature – it acts as a filter function. By comparing results of different methods, it is possible to distinguish between filter effects and the true conditions of the material and defects. We aim to isolate both in order to investigate which of the imaged features are only imaging artifacts and which deliver beneficial information for evaluation. More appropriate conclusions about the inspected object can be made. We emphasize that the combination of Journal of Composite Materials 54(27)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
