{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,23]],"date-time":"2026-03-23T10:55:37Z","timestamp":1774263337107,"version":"3.50.1"},"reference-count":47,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2026,3,23]],"date-time":"2026-03-23T00:00:00Z","timestamp":1774224000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Materials"],"abstract":"<jats:p>A novel approach for detecting preliminary signals designating upcoming entrance of a loaded system to the critical stage of impending fracture is assessed. The approach is based on the analysis of a time series of the cumulative number of acoustic events, the amplitude of which exceeds the respective average value of all the events recorded during loading. Using the \u201csliding window\u201d technique, the average slope of the evolution of this time series is quantified, either against conventional or natural time (the latter provides a more detailed view of the stage before macroscopic fracture, during which the \u201cinformation\u201d gathered is very densely packed in a short interval). For the needs of this study, data from a previously published experimental protocol are exploited. The protocol comprised notched, beam-shaped specimens, made of either plain or fiber-reinforced concrete, under three-point bending. It is concluded that the slope of the evolution of the above time series systematically attains a value equal to unity slightly before the applied load attains its peak value. The results of the present analysis are in qualitative agreement with the respective ones based on either the instantaneous frequency of generation of acoustic events or the Euclidean distance between the sources of acoustic signals.<\/jats:p>","DOI":"10.3390\/ma19061264","type":"journal-article","created":{"date-parts":[[2026,3,23]],"date-time":"2026-03-23T09:48:42Z","timestamp":1774259322000},"page":"1264","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Detecting Critical Damage in Concrete by Taking Advantage of Acoustic Events with an Amplitude Exceeding Their Mean Value"],"prefix":"10.3390","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4219-8687","authenticated-orcid":false,"given":"Dimos","family":"Triantis","sequence":"first","affiliation":[{"name":"Electronic Devices and Materials Laboratory, Faculty of Engineering, Department of Electrical and Electronics Engineering, Ancient Olive Grove Campus, University of West Attica, 250 Thivon Avenue, Egaleo, 122 44 Athens, Greece"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8484-8751","authenticated-orcid":false,"given":"Ilias","family":"Stavrakas","sequence":"additional","affiliation":[{"name":"Electronic Devices and Materials Laboratory, Faculty of Engineering, Department of Electrical and Electronics Engineering, Ancient Olive Grove Campus, University of West Attica, 250 Thivon Avenue, Egaleo, 122 44 Athens, Greece"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1580-3415","authenticated-orcid":false,"given":"Ermioni D.","family":"Pasiou","sequence":"additional","affiliation":[{"name":"Laboratory for Testing and Materials, Department of Mechanics, School of Applied Mathematical and Physical Sciences, Zografou Campus, National Technical University of Athens, 157 73 Athens, Greece"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3246-9308","authenticated-orcid":false,"given":"Stavros K.","family":"Kourkoulis","sequence":"additional","affiliation":[{"name":"Laboratory for Testing and Materials, Department of Mechanics, School of Applied Mathematical and Physical Sciences, Zografou Campus, National Technical University of Athens, 157 73 Athens, Greece"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,3,23]]},"reference":[{"key":"ref_1","unstructured":"(2022). 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