Abstract
In this paper analyses of non-contact elastic wave generation based on an air-coupled transducer (ACT) are presented. Authors compared contact piezoelectric based (PZT) wave generation, with non-contact one using ACT for a narrow frequency band excitation. Elastic wave sensing was based in both cases on a scanning laser Doppler vibrometer. The problem of ACT slope angle for the effectiveness of elastic wave modes generation is analysed. It was shown that for an excitation frequency of 40 kHz it is possible to generate A0 wave mode both in the case of PZT and ACT. Both methods of wave generation are compared based on an analysis of damage localisation results. For this purpose wave irregularity mapping (WIM) algorithm was utilised together with two attenuation compensation methods (based on energy normalisation and weighting function). Specimens in the form of simple square GFRP panel and bonded GFRP aerospace structure with omega stiffeners were investigated. The authors investigated simulated damage (Teflon inserts) and real delamination. In this research very cheap and popular, low-frequency ACT was utilised giving the possibility of realisation of low-cost excitation method. ACTs connected with a laser vibrometry sensing allows of realisation of full non-contact damage localisation method. Authors presented also non typical but very useful application of SLDV allowing to visualise the effect of acoustic wave generation in the air and determination of the pattern of generated acoustic waves. This was based on the photo-acoustic effect.
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.
