Abstract
Many traditional methods of full-field strain analysis provide convoluted or limited strain data. For instance, photoelasticity provides data related to the difference in principal strains and strain separation is problematic; whilst moire can provide in-plane or out-of-plane displacements. It has long been recognized that integrating two techniques can enhance the information available, for example holophotoelasticity; this is particularly valid when one technique operates in the infrared spectrum. Combined thermo-photo-elasticity was first attempted about a decade ago and an instrument for simultaneous capture of thermoelastic and photoelastic data has been developed and used to acquire maps of separated principal strains in complex components. When thermography and moire are combined, a new technique emerges which allows measurement of in-plane and out-of-plane strain. These novel techniques are described and examples given of their application to strain measurement in composites and complex engineering components.
