Characterisation of Orthotropic Electrical Conductivity of Unidirectional C/PAEK Thermoplastic Composites

Induction welding is a promising fusion bonding technology for carbon fibre reinforced thermoplastic composites. In this process, an alternating electromagnetic field induces eddy currents in a composite susceptor. The amount of resultant heat generated is governed by the electrical conductivity of the carbon fibre network, making accurate determination of this orthotropic property important for physics-based process simulations. This work focusses on characterisation of the conductivity in unidirectionally reinforced PAEK using the six-probe method. Special attention has been given to the distribution of the current density in the specimens during each characterisation experiment. Acquired resistance data was subsequently interpreted either analytically or numerically, depending on the current distribution detected. The longitudinal component of the conductivity tensor was found in agreement with the rule of mixtures and the transverse and through-thickness conductivities matched earlier characterisation attempts where a conventional two-probe analysis was employed.