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. (C) 2009 Elsevier Ltd. All rights reserved.