Composite piezoelectric sensors for smart composite structures

This paper reports on results of employing piezoelectric composites as sensors for detecting simulated damage events and monitoring dynamic and impact loads in composite structures. Two piezoelectric composite materials have been developed and characterized. The materials have been prepared by dispersing ceramic powder into a polymer matrix. Calcium modified lead titanate (PTCa) was used as the ceramic phase, while a non-polar epoxy resin, (Epon 828) and vinylidene fluoride trifluoroethylene (P(VDF-TrFE)), a polar copolymer, were used as the polymer matrix phases. PTCa/epoxy and PTCa/P(VDF-TrFE) composite materials were employed as embedded sensors in composite laminates to detect elastic waves propagating in such structures and to monitor transient applied loads. Furthermore, these materials could be used as sensors in health assessment techniques for composite materials where diagnostic waves methods are utilized.