Joint paper between UCC and Universidad Politécnica de Valencia (UPV) published in Ultrasonics journal
A joint paper by researchers from the Ultrasonics Research Group in UCC and the Signal Processing Group of the Institute of Telecommunication and Multimedia Applications (I-TEAM) in the Universidad Politécnica de Valencia (UPV) has been published in the Elsevier journal Ultrasonics.
The full citation is: J. Gosálbez, W. M. D. Wright, W. Jiang, A. Carrióna, V. Genovésc and I. Boscha, "Airborne non-contact and contact broadband ultrasounds for frequency
attenuation profile estimation of cementitious materials", Ultrasonics, dx.doi.org/10.1016/j.ultras.2018.03.011
Abstract - In this paper, the study of frequency-dependent ultrasonic attenuation in strongly heterogeneous cementitious materials is addressed. To accurately determine the attenuation over a wide frequency range, it is necessary to have suitable excitation techniques. We have analysed two kinds of ultrasound techniques: contact ultrasound and airborne non-contact ultrasound. The mathematical formulation for frequency-dependent attenuation has been established and it has been revealed that each technique may achieve similar results but requires specific different calibration processes. In particular, the airborne non-contact technique suffers high attenuation due to energy losses at the air-material interfaces. Thus, its bandwidth is limited to low frequencies but it does not require physical contact between transducer and specimen. In contrast, the classical contact technique can manage higher frequencies but the measurement depends on the pressure between the transducer and the specimen.
Cement specimens have been tested with both techniques and frequency attenuation dependence has been estimated. Similar results were achieved at overlapping bandwidth and it has been demonstrated that the airborne non-contact ultrasound technique could be a viable alternative to the classical contact technique.