Thermal Diffusivity Measurements on Composite Porosity Samples

Abstract

In this research the use of a phase lag technique similar to [2], is used to make quantitative measurements of diffusivity in composite porosi- ty samples. The design and calibration of a single point, noncontacting, noncryogenic thermal diffusivity measurement system is described. In addition, the fabrication of 16 ply composite samples with 1, 2, 4, and 8 percent manufactured porosity is presented along with the measurement approach used for maximum sensitivity for defect inspection. Results of the through-ply diffusivity changes due to the varying porosity levels is shown. The relationship between amount of porosity and change in diffu- sivity is analyzed using an electrical analog for modeling heat flow in the composite.