Thermal Diffusivity Measurements on Composite Porosity Samples
Porosity is a defect which can arise from moisture or gases being introduced to the resin system before cure and also during the curing process when poor bagging techniques are used. The effect of porosity results in a degradation in compressive, transverse tensile, and interlaminar shear strengths. For example, for a 1% porosity level there is approximately a 7% decrease in the interlaminar shear strength . Ultrasonics is the current state of the art NDE method for the characterization of porosity in composites using the back scatter and frequency dependent attenuation measurements. In this work a thermal diffusivity technique is investigated for the characterization of porosity in graphite composite parts. The advantages of using thermal techniques is the noncontacting nature of the measurements and the ability to capture large areas using a thermal imager.