Natural Time Analysis of Acoustic Emissions in Double Edge Notched Tension (DENT) Marble Specimens

An alternative solution to the problem of early detection of upcoming catastrophic fracture of structural elements made of marble is proposed. The solution is founded on the hypothesis that unique and hidden dynamic features of complex systems could be detected using the time series of events within the system assuming that they are analyzed in terms of Natural Time. In this direction acoustic emissions time series are analyzed aiming to reveal possible pre-failure indicators in case notched marble members are loaded mechanically. The experimental protocol consists of quasi-static, displacement controlled, tension tests with double edge notched tensile specimens made of Dionysos marble, which is the material widely used for the needs of the restoration project of the Parthenon Temple on the Acropolis of Athens. The results of the analysis are very promising and suggest that at least one valid pre-failure indicator can be identified, before non-reversible phenomena appear within the mass of the specimen.