Fiber Contact Modeling and Electrical Conductivity of Unidirectional Carbon Fiber Composites Considering Interlayer Contact

Inter-fiber contact conduction mechanisms and conductivity prediction are important for the application of electrical properties of carbon fiber-reinforced polymers (CFRP). Here, we investigate the in-plane transverse and through-thickness directional conductivity of monolayer/multilayer unidirectional carbon fiber/epoxy composites. A computational model for inter-fiber contact resistance taking into account contraction resistance and tunneling resistance was developed to predict the non-fiber direction conductivity of monolayer/multilayer unidirectional CFRP. A unidirectional fiber contact finite element analysis (FEA) model was developed to reveal the effects of tunneling and interlayer connectivity on conductivity in different directions. We found that the tunneling effect has an impact on the transverse conductivity and no effect on the longitudinal conductivity. The through-thickness conductivity shows a rapid increase as the interlayer connectivity increases. The through-thickness conductivity is sensitive to the interlayer connectivity, while the in-plane transverse conductivity keeps stable.