Adiabatic Thermography of Composite Materials

Abstract

Present evidence suggests that thermoelastic strain field measurements in composite materials can provide unique information at the structural level for applications to engineering analysis, and at the specimen and local level for scientific investigations. In addition, the unique dynamic nature of the technique, and the apparent relationship of data obtained from such a method to micro-mechanical and especially to constituent behavior and properties seems to present very special opportunities. The present paper describes the thermoelastic effect in composite materials, and the manner in which that phenomenon can be used to characterize global strain distributions, local strain distributions, stress relaxation associated with damage development, strain rate dependence, and the dependence of mechanical response on micro-constituent arrangement and behavior. In general, it is found that the thermoelastic effect provides a significant opportunity for the nondestructive evaluation of composite materials, and offers some unique opportunities, especially with regard to the investigation of the manner in,vhich the properties and performance of composites depends upon the properties, performance, and arrangement of micro-constituents.