Damage Detection for Composites Using Carbon Nanotube Film and Electrical Impedance Tomography Technology

摘要

In recent years, with the rapid development of nanotechnology, structural health monitoring (SHM) based on carbon nanotubes (CNTs) has been developed with CNTs’ excellent self-sensing ability. This paper presents an experimental methodology on detection and imaging of damages for composites by using electrical impedance tomography (EIT). A CNT film is attached on the surface of a glass fiber reinforced polymer (GFRP) plate as a smart sensing skin. EIT is then used to reconstruct the change of internal conductivity of the CNT film caused by damages with boundary voltage measurements. It is formulated as a linear inverse problem, and an inverse analysis with Tikhonov regularization is used to perform the reconstruction. Two criteria, i.e., L-curve and generalized cross validation (GCV), are adopted to determine an appropriate parameter for Tikhonov regularization. Experimental results have demonstrated that combined with CNT film’s electrical properties, EIT can successfully reconstruct the localized areas with significant conductivity reduction caused by damages, providing a versatile tool to quantitatively indicating the location and size of the damages.