Manufacturing of composite structures with a built-in network of piezoceramics

A manufacturing method was developed for integrating a network of distributed piezoceramic actuators/sensors onto laminated carbon/epoxy composite structures. The network of built-in actuators/sensors are used to monitor the health of the host composite structure by acquiring information about the condition of the structure throughout its service life.;The manufacturing method applies the printed circuit technique to fabricate a thin flexible sheet with a network of piezoceramics. It is used as an extra ply that is either inserted into or bonded onto the surface of a composite laminate to give it actuating and sensing capabilities. This layer that provides the added functionality is referred to as the "SMART Layer" (Stanford Multi-Actuator-Receiver Transduction Layer). Using the developed method, several SMART Layer prototypes have been fabricated and embedded inside carbon fiber composite laminates successfully.;Tests were conducted on composite panels integrated with the SMART Layer to validate the design and the manufacturing procedure. The results showed that the embedded SMART layer has negligible effect on the strength of the host composite structures, and that all piezoceramics of the network show uniform and consistent response.;During the manufacturing stage, the SMART Layer was conveniently put to use to monitor the cure progress of the composite, which demonstrates another useful application of built-in piezoceramics. A technique was developed to determine the completion of the autoclave cure by examining the phase change of the propagating stress wave due to resin curing. A modular computer code PMonitor was written to monitor was written to automate this monitoring process.