Experimental Investigation on the Shear Properties and Failure Mechanism of 3D MWK Glass/Epoxy Composites under Compressive Loading

This paper reports the effects of temperature and fiber architecture on the shear properties and failure mechanism of 3D MWK composites under compressive loading at room and elevated temperatures. The shear experiments of composites with three fiber architectures were performed at five different temperatures. Macro-fracture and SEM micrographs were examined to understand the deformation and shear failure mechanism. The results show that shear stress-strain curves show non-linearity and plastic fracture feature, and exhibit plastic platform at elevated temperatures. The temperature has significant effects on the shear properties which decrease significantly with increasing the temperature due to degradation of matrix properties, especially after 75 oC. The shear properties can be affected greatly by the fiber architecture and these increase significantly with the increase of 45 o direction fiber at different temperatures. The results also show that the damage and failure patterns of composites vary with the fiber architecture and temperature. At room temperature, the interfacial adhesion between fibers and matrix is high, the local delaminating and shear failure feature are prominent. At elevated temperatures, the composites become more softened, cracked and attain plasticity. The damage of matrix plastic and cracking, interface debonding, and fiber layer delaminating change significantly.