Use of PVDF Strain Sensors for Health Monitoring of Bonded Composite Patches

摘要

The use of PVDF (polyvinyldiene fluoride) piezoelectric polymer material as a strain sensor for the detection of damage in bonded composite patches is investigated in this report. These sensors offer the advantage of requiring no power to function and the sensors may be manufactured to suit any size and geometry. PVDF sensors were bonded to a specimen representative of the F-111 wing pivot fitting doubler and tested under hot/wet conditions for a series of load cases. The output of the PVDF sensors was found to vary linearly with applied load but a dependence on loading frequency was observed. Damage growth within the specimen was detected by both strain gauges and PVDF sensors. Identical trends in damage growth were observed by both sensors. The environmental durability of the PVDF sensors was found to be very good, although care needed to be taken whilst handling the sensors to avoid physically damaging them.