Estimation of the moisture absorption rate of glass fiber reinforced plastic using electromagnetic induction testing

We present a novel estimation method for the moisture absorption rate (MAR) of glass fiber reinforced plastics (GFRPs) using electromagnetic induction testing (EIT). The relationship between the permittivity and MAR were analytically calculated using a simple moisture absorption model. Moreover, we experimentally obtained the magnitude of the displacement current for dielectric specimens with known permittivity values. The equations were derived from the magnitude of the displacement current measured during EIT by combining the analytical and experimental results. To verify the validity of the proposed method using the derived equations, we applied EIT to GFRPs with different MARs. It was found that MAR can be qualitatively evaluated using the proposed method.