The electromechanical (EM) impedance technique using piezoelectric lead zirconate titanate (PZT) transducers for structural health monitoring (SHM) has attracted considerable attention in various engineering fields. In the conventional EM impedance technique, the EM admittance of a PZT transducer is used as a damage indicator. Statistical analysis methods such as root mean square deviation (RMSD) have been employed to associate the damage level with the changes in the EM admittance signatures, but it is difficult to determine the location of damage using such methods. This paper proposes a new approach by dividing the large frequency (30–400 kHz) range into sub-frequency intervals and calculating their respective RMSD values. The RMSD of the sub-frequency intervals (RMSD-S) will be used to study the severity and location of damage. An experiment is carried out on a real size concrete structure subjected to artificial damage. It is observed that damage close to the PZT changes the high frequency range RMSD-S significantly, while the damage far away from the PZT changes the RMSD-S in the low frequency range significantly. The relationship between the frequency range and the PZT sensing region is also presented. Finally, a damage identification scheme is proposed to estimate the location and severity of damage in concrete structures.
References
[1]
Park, S; Ahmad, S; Yun, CB; Roh, Y. Multiple crack detection of concrete structures using impedance-based structural health monitoring techniques. Exp Mech？2006, 46, 609–618.
[2]
Bhalla, S; Soh, CK. High frequency piezoelectric signatures for diagnosis of seismic/blast induced structural damages. NDT & E Inter？2004, 37, 23–33.
[3]
Banan, MR; Hjelmstad, KD. Parameter estimation of structures from static response. I. Computational aspects. J Struct Eng？1994, 120, 3243–3258.
[4]
Sanayei, M; Saletnik, MJ. Parameter estimation of structures from static strain measurements. I: Formulation. J Struct Eng？1996, 122, 555–562.
[5]
McCann, DM; Forde, MC. Review of NDT methods in the assessment of concrete and masonry structures. NDT & E Inter？2001, 34, 71–84.
[6]
Giurgiutiu, V; Reynolds, A; Rogers, CA. Experimental Investigation of E/M Impedance Health Monitoring for Spot-Welded Structural Joints. J Intell Mater Syst Struct？1999, 10, 802–812.
[7]
Park, G; Cudney, HH; Inman, DJ. Impedance-based health monitoring of civil structural components. J Infrastruct Syst？2000, 6, 153–160.
[8]
Park, G; Sohn, H; Farrar, CR; Inman, DJ. Overview of piezoelectric impedance-based health monitoring and patch forward. Shock Vib Dig？2003, 35, 451–463.
[9]
Liang, C; Sun, FP; Rogers, CA. Coupled electro-mechanical analysis of adaptive material system-determination of the actuator power consumption and system energy transfer. J Intell Mater Syst Struct？1994, 5, 12–20.
[10]
Yang, YW; Sabet, DB; Soh, CK. A Reusable PZT Transducer for Monitoring Initial Hydration and Structural Health of Concrete. Sensors？2010, 10, 5193–5208.
[11]
Yang, YW; Hu, YH; Lu, Y. Sensitivity of PZT impedance sensors for damage detection of concrete structures. Sensors？2008, 8, 327–346.
[12]
PI Ceramic Company, Product Information Catalog. Available online: www.piceramic.de (accessed on 15 August 2010).
[13]
Plastic DIP International, Available online: www.plastidip.com (accessed on 15 August 2010).
[14]
Sabet, DB; Yang, YW. Application of PZT sensors for detection of damage severity and Location in concrete. SPIE？2008, 7268, 726813.
[15]
Philippidis, TP; Aggelis, DG. Experimental study of wave dispersion and attenuation in concrete. Ultrasonics？2005, 43, 584–595.
[16]
Yang, YW; Sabet, DB; Tang, L; Zhang, L. Strain transfer models for macrofiber-composite strain actuators. J Mater Manufac Process？2010, 25, 237–242.
[17]
Hu, YH; Yang, YW. Wave propagation modeling of the PZT sensing region for structural health monitoring. Smart Mater Struct？2007, 16, 706–716.
[18]
Cui, Y; Zou, DH. Numerical simulation of attenuation and group velocity of guided ultrasonic wave in grouted rock bolts. J Appl GeoPhys？2006, 59, 337–344.
[19]
Yan, W; Lim, CW; Cai, JB; Chen, WK. An electromechanical impedance approach for quantitative damage detection in Timoshenko beams with piezoelectric patches. Smart Mater Struct？2007, 16, 1390–1400.
[20]
Tseng, KK; Wang, L. Smart piezoelectric transducers for in situ health monitoring of concrete. Smart Mater Struct？2004, 13, 1017–1024.
