Characterization of through-thickness thermal conductivity of wind turbine blade CFRP materials using a steady-state technique

The through-thickness thermal conductivity of unidirectional CFRP laminates was examined by means of a steady-state technique based on the Guarded Hot Plate (GHP) method. By establishing the one-dimensional heat flow through the sample and measuring the heat flux the thermal conductivity was determined. To validate the technique, measurements were conducted in two different materials with well-defined values. PTFE and Fused Silica samples were employed as reference materials. Calibration runs showed good correlation with the expected literature values for both of the reference materials. Unidirectional CFRP laminates with a fibre volume content of 57% were manufactured using Vacuum Assisted Liquid Resin Infusion in three different thicknesses to assess the measuring capabilities of the apparatus. Consistent results were obtained for all three laminate thicknesses thus validation the efficiency and accuracy of the technique.