Antenna/sensor multifunctional composites for the wireless detection of damage

Wireless structural health monitoring (SHM) techniques generally rely on the integration of sensors, transmitters, and antennas into structures; however, the ideal solution would entail the material itself acting as a monitoring system. The current work investigates the application of antenna/sensing multifunctional composites. In this technique, carbon fiber reinforced plastic (CFRP) structures are modeled as half-wavelength dipole antennas. The electrical or antenna property varies in accordance with damage occurrence and can be monitored wirelessly at a remote location. The feasibility of wireless SHM using the self-sensing antenna technique is investigated analytically and experimentally using unidirectional CFRP laminates and rotor blades of woven CFRP. The CFRP radiates radio energy well when it is used as a half-wavelength dipole antenna, and damages to the CFRP can be wirelessly detected by monitoring an increase in the resonant frequency of the CFRP antenna.