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Detection of flexural damage stages for RC beams using Piezoelectric sensors (PZT)
Karayannis, Chris G.,Voutetaki, Maristella E.,Chalioris, Constantin E.,Providakis, Costas P.,Angeli, Georgia M. Techno-Press 2015 Smart Structures and Systems, An International Jou Vol.15 No.4
Structural health monitoring along with damage detection and assessment of its severity level in non-accessible reinforced concrete members using piezoelectric materials becomes essential since engineers often face the problem of detecting hidden damage. In this study, the potential of the detection of flexural damage state in the lower part of the mid-span area of a simply supported reinforced concrete beam using piezoelectric sensors is analytically investigated. Two common severity levels of flexural damage are examined: (i) cracking of concrete that extends from the external lower fiber of concrete up to the steel reinforcement and (ii) yielding of reinforcing bars that occurs for higher levels of bending moment and after the flexural cracking. The purpose of this investigation is to apply finite element modeling using admittance based signature data to analyze its accuracy and to check the potential use of this technique to monitor structural damage in real-time. It has been indicated that damage detection capability greatly depends on the frequency selection rather than on the level of the harmonic excitation loading. This way, the excitation loading sequence can have a level low enough that the technique may be considered as applicable and effective for real structures. Further, it is concluded that the closest applied piezoelectric sensor to the flexural damage demonstrates higher overall sensitivity to structural damage in the entire frequency band for both damage states with respect to the other used sensors. However, the observed sensitivity of the other sensors becomes comparatively high in the peak values of the root mean square deviation index.
Detection of flexural damage stages for RC beams using Piezoelectric sensors (PZT)
Chris G. Karayannis,Maristella E. Voutetaki,Constantin E. Chalioris,Costas P. Providakis,Georgia M. Angeli 국제구조공학회 2015 Smart Structures and Systems, An International Jou Vol.15 No.4
Structural health monitoring along with damage detection and assessment of its severity level innon-accessible reinforced concrete members using piezoelectric materials becomes essential since engineersoften face the problem of detecting hidden damage. In this study, the potential of the detection of flexuraldamage state in the lower part of the mid-span area of a simply supported reinforced concrete beam usingpiezoelectric sensors is analytically investigated. Two common severity levels of flexural damage areexamined: (i) cracking of concrete that extends from the external lower fiber of concrete up to the steelreinforcement and (ii) yielding of reinforcing bars that occurs for higher levels of bending moment and afterthe flexural cracking. The purpose of this investigation is to apply finite element modeling using admittancebased signature data to analyze its accuracy and to check the potential use of this technique to monitorstructural damage in real-time. It has been indicated that damage detection capability greatly depends on thefrequency selection rather than on the level of the harmonic excitation loading. This way, the excitationloading sequence can have a level low enough that the technique may be considered as applicable andeffective for real structures. Further, it is concluded that the closest applied piezoelectric sensor to theflexural damage demonstrates higher overall sensitivity to structural damage in the entire frequency band forboth damage states with respect to the other used sensors. However, the observed sensitivity of the othersensors becomes comparatively high in the peak values of the root mean square deviation index.
A new damage identification approach based on impedance-type measurements and 2D error statistics
Providakis, Costas,Tsistrakis, Stavros,Voutetaki, Maristella,Tsompanakis, Yiannis,Stavroulaki, Maria,Agadakos, John,Kampianakis, Eleftherios,Pentes, George Techno-Press 2015 Structural monitoring and maintenance Vol.2 No.4
The electro-mechanical impedance (EMI) technique makes use of surface-bonded lead zirconate titanate (PZT) patches as impedance transducers measuring impedance variations monitored on host structural components. The present experimental work further evaluate an alternative to the conventional EMI technique which performs measurements of the variations in the output voltage of PZT transducers rather than computing electromechanical impedance (or admittance) itself. This paper further evaluates a variant of the EMI approach presented in a previous work of the present authors, suitable, for low-cost concrete structures monitoring applications making use of a credit card-sized Raspberry Pi single board computer as core hardware unit. This monitoring approach is also deployed by introducing a new damage identification index based on the ratio between the area of the 2-D error ellipse of specific probability of EMI-based measurements containment over that of the 2-D error circle of equivalent probability. Experimental results of damages occurring in concrete cubic and beam specimens are investigated under increasing loading conditions. Results illustrate that the proposed technique is an efficient approach for identification and early detection of damage in concrete structures.