Fundamental Understanding of Piezoelectric （压电陶瓷的基本理解）.pdfVIP

Fundamental Understanding of Piezoelectric Strain Sensors JAYANT SIROHI* AND INDERJIT CHOPRA Alfred Gessow Rotorcraft Center, Department of Aerospace Engineering, University of Maryland, College Park, MD 20742 ABSTRACT: This paper investigates the behavior of piezoelectric elements as strain sensors. Strain is measured in terms of the charge generated by the element as a result of the direct piezoelectric ef- fect. Strain measurements from piezoceramic (PZT) and piezofilm (PVDF) sensors are compared with strains from a conventional foil strain gage and the advantages of each type of sensor are dis- cussed, along with their limitations. The sensors are surface bonded to a beam and are calibrated over a frequency range of 5–500 Hz. Correction factors to account for transverse strain and shear lag ef- fects due to the bond layer are analytically derived and experimentally validated. The effect of tem- perature on the output of PZT strain sensors is investigated. Additionally, design of signal condition- ing electronics to collect the signals from the piezoelectric sensors is addressed. The superior performance of piezoelectric sensors compared to conventional strain gages in terms of sensitivity and signal to noise ratio is demonstrated. INTRODUCTION their superior noise immunity as compared to differentiated signals from conventional foil gages has been demonstrated. IEZOELECTRIC elements are commonly used in smart The correlation between the piezoelectric