Temperature effect on all-inkjet-printed nanocomposite piezoresistive sensors for ultrasonics-based health monitoring

Abstract The sensing performance of nanocomposite piezoresistive sensors in acquiring broadband acousto-ultrasonic wave signals is scrutinized in an extensive regime of temperature variation from −60 to 150 °C, which spans the thermal extremes undergone by most aircraft and spacecraft. Ultralight and flexible, the sensors are all-inkjet-printed using a drop-on-demand additive manufacturing approach, and then optimized sensitive to the ultraweak disturbance induced by acousto-ultrasonic waves in virtue of quantum tunneling effect. Under high-intensity thermal cycles from −60 to 150 °C, the sensors have proven stability and accuracy in responding to signals in a broad band from static to half a megahertz. Compared with conventional broadband sensors such as piezoelectric wafers, this genre of inkjet-printed nanocomposite sensors avoids the influence of increased dielectric permittivity during the measurement of high-frequency signals at elevated temperatures. Use of the sensors for characterizing undersized cracks in a typical aerospace structural component under acute temperature variation has spotlighted the alluring application potentials of the all-inkjet-printed nanocomposite sensors in implementing in-situ structural health monitoring for key aircraft and spacecraft components.