Thermal distribution in unidirectional carbon composite material due to the direct heating and microwave influence visualized by a thermo-elastic optical indicator microscope

The experimental setup of the thermo-elastic optical indicator microscope (TEOIM) and Carbon/PEEK sample pattern with anisotropic thermal conductivity directions marked by red arrows (KL > KT) with the heat affected zone ellipse in unidirectional lamina experimentally visualized heat TEOIM. [Display omitted] •Thermal and electromagnetic properties of anisotropic carbon fibers investigated.•Field distribution was visualized using thermo-elastic optical indicator microscope.•Microwave distribution depends on the orientation of carbon fibers and polarization.•Longitudinal conductivity exceeded the transverse conductivity by about 4.6 times.•The composite material acts as an EM polarizer in the microwave (9–15 GHz) region. Two experiments were performed to investigate the thermal and electromagnetic (EM) properties of unidirectional carbon fiber/polyether ether ketone (PEEK) composite materials. Thermal distribution in the directly heated carbon/PEEK lamina was visualized using a thermo-elastic optical indicator microscope (TEOIM). In an additional experiment, the EM properties of carbon/PEEK composite material in the 9–15 GHz microwave frequency range were investigated. The microwave near-field (MWNF) distribution of carbon/PEEK composite lamina was visualized by using TEOIM. The microwave heating mechanism and the MWNF distribution strongly depend on the relative orientation of the EM polarization and carbon fibers direction. Both experiments were simulated in the COMSOL Multiphysics interface, which show good agreement with the experimental data.