Practical issues related to the application of the electromechanical impedance technique in the structural health monitoring of civil structures: I. Experiment

The advent of smart materials such as the piezo-impedance transducer (lead zirconate titanate, PZT) and optical fiber (FBG) has ushered in a new era in the field of structural health monitoring (SHM) based on non-destructive evaluation (NDE). So far, successful research and investigations conducted on the electromechanical impedance (EMI) technique employing a piezo-impedance transducer are often laboratory based and mainly theoretical. Real-life application of the technique, especially under harsh environments, has frequently been questioned. In this research project, investigative studies were conducted to evaluate the problems involved in real-life applications of the EMI technique, attempting to reduce the gap between theory and application. This two-part paper presents a series of experimentation (part I) and numerical verification (part II) on various issues related to real-life application, including the durability of PZT transducers, and the effects of bonding and temperature under conceivable nominal construction site conditions. The repeatability of electrical admittance signatures acquired from the PZT patches surface bonded on aluminum structures was found to be excellent up to a period of one and a half years. Experimental investigations revealed that the bonding thickness should preferably be thinner than one-third of the patch to avoid any adverse effect caused by the PZT patch's resonance on the admittance signatures which reflect the host structural behavior. On the other hand, the effect of temperature on the admittance signatures was found to be closely related to the thickness of bonding, as an increase in temperature would reduce the stiffness of the bonding layer, thus affecting strain transfer. It was concluded that PZT patches with thick bonding thickness and high frequency of excitation are undesirable, especially at elevated temperatures.

[1]  E. Crawley,et al.  Use of piezoelectric actuators as elements of intelligent structures , 1987 .

[2]  Fu-Kuo Chang,et al.  Finite element analysis of composite structures containing distributed piezoceramic sensors and actuators , 1992 .

[3]  Craig A. Rogers,et al.  Coupled Electro-Mechanical Analysis of Adaptive Material Systems — Determination of the Actuator Power Consumption and System Energy Transfer , 1994 .

[4]  Craig A. Rogers,et al.  Automated real-time structure health monitoring via signature pattern recognition , 1995, Smart Structures.

[5]  Craig A. Rogers,et al.  Effects of temperature on the electrical impedance of piezoelectric sensors , 1996, Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring.

[6]  C. Liang,et al.  Electro-mechanical impedance modeling of active material systems , 1996 .

[7]  Craig A. Rogers,et al.  Qualitative impedance-based health monitoring of civil infrastructures , 1998 .

[8]  Daniel J. Inman,et al.  Impedance-Based Structural Health Monitoring for Temperature Varying Applications , 1999 .

[9]  Daniel J. Inman,et al.  An Integrated Health Monitoring Technique Using Structural Impedance Sensors , 2000 .

[10]  Daniel J. Inman,et al.  IMPEDANCE-BASED HEALTH MONITORING OF CIVIL STRUCTURAL COMPONENTS , 2000 .

[11]  Gui-Rong Liu,et al.  A Modified Electro-Mechanical Impedance Model of Piezoelectric Actuator-Sensors for Debonding Detection of Composite Patches , 2002 .

[12]  Mark J. Schulz,et al.  Piezoelectric Materials at Elevated Temperature , 2003 .

[13]  Chee Kiong Soh,et al.  Effects of adhesive on the electromechanical response of a piezoceramic-transducer-coupled smart system , 2003, Other Conferences.

[14]  Andrei N Zagrai,et al.  Damage Identification in Aging Aircraft Structures with Piezoelectric Wafer Active Sensors , 2004 .

[15]  Suresh Bhalla,et al.  A mechanical impedance approach for structural identification, health monitoring and non-destructive evaluation using piezo-impedance transducers. , 2004 .

[16]  Bin Lin,et al.  DURABILITY AND SURVIVABILITY OF PIEZOELECTRIC WAFER ACTIVE SENSORS FOR STRUCTURAL HEALTH MONITORING USING THE ELECTROMECHANICAL IMPEDANCE TECHNIQUE , 2004 .

[17]  Stanislaw Pietrzko,et al.  The influence of temperature and bonding thickness on the actuation of a cantilever beam by PZT patches , 2004 .

[18]  Suresh Bhalla,et al.  Structural Health Monitoring by Piezo-Impedance Transducers. I: Modeling , 2004 .

[19]  Jianfeng Xu,et al.  Electromechanical Impedance-Based Structural Health Monitoring with Evolutionary Programming , 2004 .

[20]  Jianfeng Xu,et al.  Generic Impedance-Based Model for Structure-Piezoceramic Interacting System , 2005 .

[21]  Suresh Bhalla,et al.  Structural identification and damage diagnosis using self-sensing piezo-impedance transducers , 2006 .

[22]  Yaowen Yang,et al.  Wave propagation modeling of the PZT sensing region for structural health monitoring , 2007 .

[23]  Jian Zhao,et al.  Monitoring of rocks using smart sensors , 2007 .

[24]  Yaowen Yang,et al.  Influence of loading on the electromechanical admittance of piezoceramic transducers , 2007 .

[25]  Chao Wang,et al.  Application of Multiplexed FBG and PZT Impedance Sensors for Health Monitoring of Rocks , 2008, Sensors.

[26]  Yaowen Yang,et al.  Electromechanical impedance modeling of PZT transducers for health monitoring of cylindrical shell structures , 2008 .

[27]  Yaowen Yang,et al.  Sensitivity of PZT Impedance Sensors for Damage Detection of Concrete Structures , 2008, Sensors.