1 May 1996 Effects of temperature on the electrical impedance of piezoelectric sensors
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Abstract
Piezoelectric materials have been known to have temperature dependency regarding their basic properties, such as the dielectric constant and the piezoelectric coefficient. In this paper, this temperature dependency is investigated. The motivation of this work is linked to the impedance-based nondestructive evaluation (NDE) technique which employs piezoceramic (PZT) sensors for tracking changes in the structural impedance, by measuring the electrical impedance, to qualitatively identify damage. However, for this NDE technique to be successful in all types of environments, it must be insensitive to temperature variations. As mentioned earlier, piezoelectric materials have strong temperature dependency and a temperature compensation procedure is necessary. The approach used in this paper is empirical due to the complexity of the thermoelectromechanical constitutive modeling. Through experimental investigation, it was found that temperature will have the effect of shifting the electrical impedance magnitude of the piezoelectric sensor, while leaving the impedance phase unaffected. For a PZT PSI-5A, the variation was found to be linear in the 80 degree F to 160 degree F temperature range. To characterize the temperature effects in piezoelectric materials, a temperature coefficient which is independent of frequency has been defined. Finally, based on the defined temperature coefficient, a simple temperature compensation technique has been implemented successfully, eliminating the effects of temperature on PZT sensors while not eliminating the effects of temperature on the structure.
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Karthik Krishnamurthy, Karthik Krishnamurthy, Frederic Lalande, Frederic Lalande, Craig A. Rogers, Craig A. Rogers, } "Effects of temperature on the electrical impedance of piezoelectric sensors", Proc. SPIE 2717, Smart Structures and Materials 1996: Smart Structures and Integrated Systems, (1 May 1996); doi: 10.1117/12.239033; https://doi.org/10.1117/12.239033
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