Characterization of electrical conductivity of carbon fiber reinforced plastic using surface potential distribution

Abstract

A new method of evaluating electrical conductivity in a structural material such as carbon fiber reinforced plastic (CFRP) using surface potential is proposed. After the CFRP was charged by corona discharge, the surface potential distribution was measured by scanning a vibrating linear array sensor along the object surface with a high spatial resolution over a short duration. A correlation between the weave pattern of the CFRP and the surface potential distribution was observed. This result indicates that it is possible to evaluate the electrical conductivity of a material comprising conducting and insulating regions.

System for Visualizing Surface Potential Distribution to Eliminate Electrostatic Charge

“…By vibrating the detection unit side, a spatial displacement is generated, and an AC-modulated signal is induced in the electrodes of the detection unit. The charge Q (C) is calculated as Q = Δ VεS /( d ± x ), where ∆ V (V) is the potential difference between the maximum and the minimum voltages detected by a sensor; ε (F/m), the permittivity in air; S (m 2 ), the area of the sensor; d (m), the distance between the sensor and the object; and x (m), the amplitude of vibration of the sensor [ 30 ]. Here, when the charge Q , permittivity ε , area S , and distance d are constant, the potential difference ∆ V is given by Δ V = a ± bx , where a and b are constant.…”

“…Each sensor was connected directly to the lock-in amplifier from a plate electrode. These sensors were not biased to any voltage, and the alternating current voltage and phases detected by the individual sensors were measured simultaneously by means of the individual interlock amplifier [ 30 ].…”

“…where ∆V (V) is the potential difference between the maximum and the minimum voltages detected by a sensor; ε (F/m), the permittivity in air; S (m 2 ), the area of the sensor; d (m), the distance between the sensor and the object; and x (m), the amplitude of vibration of the sensor [30]. Here, when the charge Q, permittivity ε, area S, and distance d are constant, the potential difference ∆V is given by…”

“…Sensors 2021, 21, x 3 of 12 sors were not biased to any voltage, and the alternating current voltage and phases detected by the individual sensors were measured simultaneously by means of the individual interlock amplifier [30]. Three test samples (1, 2, and 3) were used to evaluate the performance of this system.…”

“…We have previously developed a system consisting of a line-type array sensor, a vibration generator, and a scanning mechanism to process the signals of each sensor simultaneously [ 29 , 30 ]. In the present study, we develop a system that measures the charge distribution rapidly with high spatial resolution by optimizing the scanning speed of the array sensor in the uniaxial direction.…”