Search

This work proposes a smart eddy current testing (ET) method for identifying crack orientation by introducing an additional electrically anisotropic plate. The key idea of the proposed approach is to insert the anisotropic plate between an eddy current (EC) probe and a test piece for controlling the electromagnetic field. Distribution of the space magnetic field and induced current density was numerically investigated. The simulation results showed that deformation of the magnetic field distribution occurs in the case of inserting an anisotropic plate. Meanwhile, it makes the magnetic field distribution directional and its direction will be changeable and controllable by rotating angle θ of the anisotropic plate. Furthermore, redistribution of the induced current density can be observed in the test piece, which results in two identical peak areas, and they are symmetric with respect to an axis perpendicular to the rotation angle. Subsequently, output voltage of the EC probe was calculated to quantitatively analyze the sensitivity for identifying crack orientation. Findings show that the output voltage from the probe was affected by the angle between the conductivity angle θ of the anisotropic plate and the crack orientation. [ABSTRACT FROM AUTHOR]

The aim of this paper is to investigate the cause of nonlinear behavior mechanism of change in electrical resistance of 3D printed carbon fiber reinforced plastics (CFRP) due to tensile loading. The electrical resistance change method is a nondestructive testing method that helps detect strain and damage. In previous research for electrical resistance change method applied to 3D printed CFRP, the change in electrical resistance is different compared with the one of conventional CFRP. The behavior makes health monitoring difficult, and the phenomenon needs to be clarified. In this research, we focused on the electrode fabrication method and viscoelasticity effect during cyclic tests. Polishing and laser processing are used as surface treatments for electrode fabrication. Consequently, the treatments are found to affect the reverse piezo-resistivity. In addition, the decrease in electrical resistance depends on the test speeds of cyclic test. The viscoelasticity is found to affect the nonlinear behavior. [ABSTRACT FROM AUTHOR]