On the anisotropic behavior of electrodes for electrical‐based monitoring of CFRP laminated composites

Abstract

Electrical impedance tomography (EIT) is a promising structural health monitoring technique for carbon fiber‐reinforced polymer (CFRP) composites. EIT technique has been specifically adopted as a non‐destructive testing method along with the electrical characterization methods. Electrodes are the primary component in any EIT system because they act as an interface connecting the instrument/hardware to the structure under inspection. Simulation of electrical inspection of CFRP usually assumes the electrodes to be electrically isotropic interfaces. We show here that such isotropic assumption is a very poor approximation. We experimentally investigated the electrodes contact impedance behavior on CFRP‐laminated composite specimens for different surface processing (sanding, CO2 laser, and Yb‐fiber laser). The effective electrical responses of electrodes are characterized in‐depth, so an accurate description can be proposed. Our findings emphasize that the electrodes contact impedance is strongly anisotropic, and varies largely between the on‐axis (along surface fibers) and the off‐axis (bias and perpendicular to the surface fibers) for all tested surface processing. POLYM. COMPOS., 2018. © 2018 Society of Plastics Engineers

Experimental probe into the femtosecond laser ablation thresholds in carbon fiber reinforced polymer and assessment of the measurement theories

“…7 CFRP has the characteristics of low interlayer strength and anisotropy of microstructure. 8 There are significant differences between the physical and chemical properties of carbon fiber and resin matrix. Therefore, mechanical processing is prone to encounter problems such as delamination and carbon fiber damage.…”

“…CFRP can be produced with a variety of structures and functions by combining different types of carbon fiber and resin matrix 7 . CFRP has the characteristics of low interlayer strength and anisotropy of microstructure 8 . There are significant differences between the physical and chemical properties of carbon fiber and resin matrix.…”

Damage detection of CFRP laminates based on Adamax-INN model for EIT

“…However, each of these methods has its own limitation for the application of CFRP detection. As a non-radiative, real-time, visualizable, easy-operating and low-cost detecting technique, electrical impedance tomography (EIT) reconstructs the internal conductivity distribution of the CFRP material by measuring boundary voltage signals, and the damaged area can be located based on the difference in conductivity distribution between the damaged and intact area [8]. EIT has garnered widespread interest in recent years as a potential method for CFRP testing, however, it has always been plagued by the underdetermination of the inverse problem, which has severely limited the resolution and accuracy of the reconstructed images.…”

Electrical-mechanical behaviors of three-dimensional braided composites under three-point bending

“…Continuous structural health monitoring technique of the carbon fiber reinforced polymer (CFRP) has been applied to the aerospace field for improving structure safety 1–3 with a lower cost. A number of real-time damage monitoring methods on CFRP composites have been developed 4–10 recently. The CFRP composites have self-monitoring capability due to the electrical conductivity of carbon fibers.…”