<title>Embedded cure monitor, strain gauge, and mechanical state estimator</title>

Abstract

Pressed PZT Piezoelectric disks were embedded in a range of materials and their properties monitored under a wide range of conditions. The output depends on the temperature and pressure exerted on the PZT by the surrounding material and by the mechanical impedance mismatch between the embedded PZT and the surroundings. By monitoring the "Q" of the PZT (the ratio of energy stored to energy dissipated) it was found that the PZT discs could be used as cure monitors, strain gauges, and as embedded dynamic mechanical property estimators. This latter property is a means of gauging the "health of the material", and its degradation with time. These sensors were part of the MTSIUS Navy embedded sensor program, so the sensors could be addressed and read remotely. The techniques, the data and the applications are discussed in this paper.