Adaptable Synchronous Detection for the SHM of Composite Component: Autonomous FPAA Architecture on Polyimide Film

Overview & Synopsis

Structural Health Management strategies usually involve monitoring complex components, during their working life. Carbon fiber reinforced polymer components are becoming more and more used, throughout the structural engineering fields, because of their superior mechanical properties. Moreover, due to their construction, these materials open the path for new Òsmartî components, with integrated sensors and monitoring capabilities. Flexible circuits are essential in this context. In order to adapt to complex geometries, sensors and their connectivity have to be flexible and as un-intrusive as possible. Following previous work, aimed at inserting sensors with flexible connectivity in between the sheets of carbon fibers, we conceived and implemented a reconfigurable acquisition system that can be easily adapted to perform strain measurements in various EM5 noise conditions. This paper presents a comparison between three circuits dedicated to strain measurement using a commercial strain gauge and flexible connectivity on Kapton2. The first circuit consists of a classic Wheatstone bridge under continuous voltage. The second uses the synchronous detection principle with classic circuits and functions. The third innovates upon the synchronous detection principle by implementing several functions in a reprogrammable analog chip called FPAA (Filed Programmable Analog Array). The analysis of these circuits shows the added value of using reconfigurable devices with flexible connectivity and sensors in order to provide a universal solution for the monitoring of complex components.