Damage initiation and development in textile composites: a gallery

The paper presents results of experimental observations of damage processes during tensile quasi-static and fatigue loading for carbon/epoxy textile composites: (1) woven fabrics; (2) non-crimp fabrics (NCF); (3) structurally stitched NCF. The test methodology includes, apart from the “normal” tensile testing, registration of acoustic emission and full-field measurements of strains on the surface of the sample. The damage in the samples loaded to a certain characteristic level of strain or certain number of fatigue cycles, is studied using X-ray inspection and micrography of the cross-sections. Analogies between damage development in quasi-static tensile test and tension-tension fatigue are analyzed and links between the damage initiation thresholds in quasi-static tests and fatigue life are established. Meso-level finite element modelling is performed for quasi-static tension of NCF and woven fabric composites, using damage mechanic approach to model the progressive damage.