Impedance-Based Structural Health Monitoring for Temperature Varying Applications

• Published in: JSME International Journal Series A Solid Mechanics and Material Engineering Vol. 42; no. 2; pp. 249 - 258
• Main Authors: PARK, Gyuhae, KABEYA, Kazuhisa, CUDNEY, Harley H., INMAN, Daniel J.
• Format: Journal Article
• Language: English
• Published: Tokyo The Japan Society of Mechanical Engineers 1999; Japan Society of Mechanical Engineers; Japan Science and Technology Agency
• Subjects: Applied sciences; Damage Detection; Exact sciences and technology; Fundamental areas of phenomenology (including applications); General equipment and techniques; Impedance Measurement; Industrial metrology. Testing; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Measurement and testing methods; Measurement methods and techniques in continuum mechanics of solids; Mechanical engineering. Machine design; Non-Destructive Evaluation; Physics; Piezoelectric Material; Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing; Solid mechanics; Structural and continuum mechanics; Structural Health Monitoring; Temperature Compensation; Transducers; Piezoelectric sensor; Mechanical impedance; Temperature effect; Experimental study; Modeling; Wear; Error correction; Measurement method; Non destructive test; Temperature fluctuation; Monitoring; Intelligent system; Damaging
• ISSN: 1344-7912; 1347-5363
• DOI: 10.1299/jsmea.42.249

A new structural health monitoring technique capable of in-service, on-line incipient damage detection has been proposed by the Center for Intelligent Material Systems and Structures, Physical changes in a structure cause changes in the mechanical impedance. Due to the electromechanical coupling in piezoelectric materials, this change causes a change in the electrical impedance of the piezoelectric sensor. Hence, by monitoring the electrical impedance and comparing this to a baseline measurement, we can determine when structural damage has either occurred or is imminent. However, in almost all practical health monitoring applications, the structure being monitored is constantly undergoing change due to the effect of external boundary conditions. One of the important factors that leads to this change is the temperature variations. In this paper, temperature effects on the electrical impedance of piezoelectric materials and the structures have been investigated. A computer algorithm was developed which incorporates temperature compensation into our health monitoring applications. Three experimental investigations were performed successfully under the temperature varying condition, in the range of 25 to 75°C, including a bolted pipe structure, composite reinforced aluminum and precision part such as gears. It was found that, by this compensation procedure, the impedance based health monitoring tehcnique is able to detect damage in the incipient stage, even with the presence of significant temperature variation.