Preparation and application of piezoelectric ceramic/epoxy resin composite sensor based on Lamb wave

The structure of wind turbine blades and aircraft wings is a kind of large-area curved plate-like structure. The structure health monitoring (SHM) technique based on Lamb wave is highly sensitive to slight damage, which is one of the techniques that have wide application prospect. The traditional Lamb wave sensors are generally made of piezoelectric ceramic, which features brittleness and high hardness, therefore traditional PZT ceramic sensors are not suitable for the detection on curved surface structures. In this study, a new type of flexible 0-3 piezoelectric composite was prepared by combining PZT ceramic powder with epoxy resin. The influences of mass ratio of PZT ceramic powder and epoxy resin, polarization electric field, polarization temperature, polarization time and etc. on the PZT composite performance parameters were investigated. Multiple factor orthogonal experiments were conducted to determine the optimal polarization processing parameters for material preparation. Experiments were performed to investigate the sensing response characteristics of the sensor made of the PZT composite to lamb wave. The sensing response characteristics were compared with those of the sensing elements made of MFC, PVDF and the traditional piezoelectric disc. The prepared sensor was applied to airfoil surface plate and the elliptic positioning method was used to carry out damage detection. The study results show that the fabricated piezoelectric composite material sensor possesses good sensing response characteristic. The sensor can nicely fit the curved plate surface. The acquired Lamb wave signal is more accurate compared with the Lamb wave signal acquired using traditional piezoelectric disc that can only partially fit the curved plate surface. So, the research provides a new type of flexible piezoelectric sensing technique for the SHM of curved plate structures. © 2019, Science Press. All right reserved.