Vibration and impact monitoring of a composite-wing model using piezoelectric paint

This study investigates a piezoelectric paint sensor for large area sensing applications, and its sensing characteristics under dynamic loading conditions such as impact and vibration. The piezoelectric paint is composed of the Pb(Nb,Ni)O3-Pb(Zr,Ti)O3 (PNN-PZT) powder and epoxy resin. The PNN-PZT is a kind of soft piezoelectric material that offers many advantages such as high piezoelectric properties, easy poling, and so on. The PNN-PZT/epoxy paint sensor can be easily applied to various engineering structures, even to those having a complex geometry or curved shapes because of its flexibility. In this study, the PNN-PZT/epoxy paint was coated on a composite-wing model. One electrode was made on the upper surface of the piezoelectric paint, while the graphite/epoxy composite structure itself was used as the other electrode. Then poling was conducted at room temperature (20 °C) under a 4 kV/mm electric field for 10 min. When the composite-wing model was subjected to free-vibration, its vibration response was monitored by measuring the output voltage of the piezoelectric paint sensor; when the composite-wing model was impacted by an impact hammer, its impact signal was also measured by the piezoelectric paint sensor. The vibration and impact test results showed that the PNN-PZT/epoxy paint sensor captured the dynamic responses of the composite-wing structure very well. We believe that the piezoelectric paint sensor can be useful in many engineering applications such as real-time vibration and impact monitoring, damage detection, nondestructive structural health monitoring, and so on.