Applications of smart piezoelectric materials in a wireless admittance monitoring system (WiAMS) to structures-tests in RC elementsApplications of smart piezoelectric materials in a wireless admittance monitoring system (WiAMS) to structures-tests in RC elements Peer-Reviewed Journal Publication Δημοσίευση σε Περιοδικό με Κριτές 2018-06-282016enThe application of an innovative real-time structural health monitoring system is studied through tests performed on flexural and shear-critical reinforced concrete elements subjected to monotonic and cyclic loading. The test set-up involves a Wireless impedance/Admittance Monitoring System (WiAMS) that comprises specially manufactured small-sized portable devices to collect the voltage frequency responses of an array of smart piezoelectric transducers mounted on structural members of reinforced concrete constructions. Damage detection and evaluation is achieved using the in-situ measurements of the integrated piezoelectric sensors/actuators signals at the healthy state of the member and at various levels of damage during testing. Three different installations of Piezoelectric lead Zirconate Titanate (PZT) transducers are examined: (a) epoxy bonded PZTs on the surface of the steel reinforcing bars of the flexural elements, (b) PZTs embedded inside the concrete mass of the shear-critical beams and (c) externally epoxy bonded PZTs attached to the concrete surface of the tested elements. The smart piezoelectric materials have been pre-installed before testing based on the potential flexural and shear cracking of the elements. Quantitative assessment of the examined damage levels using values for the statistical damage index is also presented and discussed. Voltage signals and index values acquired from the PZTs' measurements using the proposed wireless monitoring technique demonstrated obvious discrepancies between the frequency response of the healthy and the examined damage levels for every tested element. These differences clearly indicate the presence of damage, whereas their gradation reveals the magnitude of the occurred damage. Promising results concerning the prediction of the forthcoming fatal failures at early damage stages have also been derived.http://creativecommons.org/licenses/by/4.0/Case Studies in Construction Materials51-18Chalioris_el_al_Case Stud. Constr. Mater._5_2016.pdfChania [Greece]Library of TUC2018-06-28application/pdf6.9 MBfree Chalioris Constantin E. Karayannis Chris G. Angeli Georgia M. Papadopoulos Nikos A. Favvata Maria J. Providakis Konstantinos Προβιδακης Κωνσταντινος Elsevier Damage assessment Flexural tests PZT Piezoelectric lead zirconate titanate RC Reinforced concrete Shear SHM Structural health monitoring