Determination of Lateral Diffusivity of CFRP Composite Using Active Thermography

摘要

Actual anisotropic material properties of composite structural members are important for carrying out several analyses including structural health monitoring and nondestructive evaluation. These properties are affected by the fabrication process, service conditions, as well as distributed damage in the material, and hence are not readily available. While the through the thickness thermal conductivity is easily determined using thermography, the lateral thermal diffusivity is difficult to measure.;In this study, the heat flow around a circular shadow in a flash thermography experiment is used for determining the lateral thermal conductivity. A quasi-isotropic laminate and a unidirectional laminate are used to determine the respective in-plane properties. Experiments were performed to record the transient heat flow pattern during the cooling period and the data are processed using standard signal processing techniques employed in flash thermography. These experiments were also simulated using finite element analysis, for a range of lateral thermal conductivities. The sequence of images from the experiments were compared with those obtained from finite element analysis to determine the closest match, and from such a correlation, the lateral thermal diffusivity is determined. The results from this study is compared with the available values found in literature.