Issue 50

I. Stavrakas et alii, Frattura ed Integrità Strutturale, 50 (2019) 573-583; DOI: 10.3221/IGF-ESIS.50.48 573 Focused on the research activities of the Greek Society of Experimental Mechanics of Materials Damage evolution in marble under uniaxial compression monitored by Pressure Stimulated Currents and Acoustic Emissions Ilias Stavrakas Electronic Devices and Materials Laboratory, University of West Attica, Greece ilias@uniwa.gr , http://orcid.org/0000-0001-8484-8751 Stavros K. Kourkoulis National Technical University of Athens, Department of Mechanics, Athens, Greece stakkour@central.ntua.gr, https://orcid.org/0000-0003-3246-9308 Dimos Triantis Electronic Devices and Materials Laboratory, University of West Attica, Greece triantis@uniwa.gr, http://orcid.org/0000-0003-4219-8687 A BSTRACT . The spatiotemporal evolution of damage in marble specimens under uniaxial compression is monitored using Pressure Stimulated Currents (PSCs) and Acoustic Emissions (AEs). The novelty of the study is the use of an integrated grid of sensors (instead of a single pair of electrodes) to detect the weak electrical signals, emitted during loading. The use of such a grid of sensors does indeed enhance the capabilities of the PSC technique providing valuable information about the initiation and propagation of micro-fracturing at the interior of the specimens. The experimental results indicate that both the im- proved b-value of the AE hits and the energy of the PSCs offer information about the proximity of the applied stress to that causing fracture. It is thus concluded that both quantities could be considered as pre-failure indicators. K EYWORDS . Pressure Stimulated Currents; Acoustic Emissions; Improved b- value; Damage evolution; Uniaxial compression; Marble. Citation: Stavrakas, I., Kourkoulis, S.K., Tria- ntis, D., Damage evolution in marble under uniaxial compression monitored by Pressure Stimulated Currents and Acoustic Emissions, Frattura ed Integrità Strutturale, 50 (2019) 573-583. Received: 16.01.2019 Accepted: 15.05.2019 Published: 01.10.2019 Copyright: © 2019 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. I NTRODUCTION nlightening the spatiotemporal evolution of damage at the interior of structural elements under mechanical load is an interesting, though demanding, task of Mechanics of Materials and Engineering. Its importance becomes evident by taking into account that, in case damage evolution is properly monitored, the respective data could be used, among others, as tools for assessing the element’s remaining life or, equivalently, as valuable pre-failure indicators. E