Characterization of SiC/SiC composites damage mechanisms using Digital Image Correlation at the tow scale

Digital Image Correlation (DIC) is applied to a 2D braided SiC/SiC composite tube loaded in tension to characterize the displacement field within a single periodic pattern. A method is proposed to process the large amount of information obtained to get a few relevant kinematic quantities. The openings of several cracks, appearing within the textile pattern, and the kinematics of the surrounding uncracked blocks, evaluated as a function of the loading, provide a quantitative description of the periodic pattern deformation. In particular, this experimental data demonstrates the importance of textile effects (reorientation of the tows towards the tensile test direction) on the macroscopic behavior. A new approach to the modeling of these composites is finally proposed, based on the characterization of the deformation mechanisms and simple enough for an application to structural analysis.