Interlaminar shear strain measurement on angle-ply laminate free edge using digital image correlation

Because only coarse polishing is required in order for Digital Image Correlation (DIC) to be used, such a technique has been used to study interlaminar shear strain on the free edges of carbon/epoxy laminates. Pure UD and quasi UD have been considered. The measurement uncertainties are small when compared to measured fields. The correlation parameters of DIC have been optimized to highlight the strain gradients. DIC results for pure-UD samples show high interlaminar strain gradients with a non-linear behaviour and local damage close to inter-ply interfaces. Measurements of quasi-UD samples highlight the microstructure influence on the spatial repartition of free edge strain gradients.