Use of digital image correlation to measure strain recovery in particle toughened thermoset resins

A methodology for finding the yield point of epoxy resins, both neat and particulate toughened, is described. Trends of the effect that particulate filling has on the time dependent response of these materials were constructed from observations made with stereo-based digital image correlation (3D-DIC), namely, creep and stress relaxation at constant load. The use of 3D-DIC also enabled the observation of differences in deformation mechanisms resulting from the particle addition. The focus is put on the technique’s potential to characterize materials and produce clear relationships between composition and mechanical strain response of any composition. The methodology proposed herein allows the observation and study of multiple deformation mechanisms from a single test, and thus can potentially minimize the number of specimens needed for a comprehensive test campaign.