Electrical Conductivity Mapping Evaluation of a Unidirectional Carbon Fiber Composite Material Based on a Multiobjective Inversion Method

Abstract

In this paper, we propose an approach for determining the two-dimensional electrical conductivity mapping of an anisotropic unidirectional carbon fiber reinforced polymer (UD CFRP). The approach consists of subdividing the UD CFRP ply into several identical virtual zones and determining the longitudinal and transverse electrical conductivity components for each zone by applying an inverse problem technique with multiple cost functions. Following a clearly defined measurement protocol, experimental measurements were carried out on the UD CFRP ply to obtain DC electrical resistances between pairs of electrodes placed at the ends of the bordering zones. This was followed by a numerical calculation of the DC resistances for all electrode pairs using a finite element model (FEM). A multi-objective simulated annealing algorithm was applied to minimize the cost functions which are expressed as the difference between the calculated resistances and those measured for all electrode pair placement positions. The numerical model and experimental setup were validated using a conductive material with known electrical conductivity. The proposed multi-zone conductivity evaluation approach was first verified using numerical results and then successfully applied to a UD CFRP ply.