Static behavior characteristics of hybrid composites with nonwoven carbon tissue

Mechanical behavior characteristics of hybrid composites with nonwoven carbon tissue (NWCT) are investigated under static tensile loadings. The hybrid composite consists of unidirectional CFRP and NWCT. The NWCT is composed of short fibers, discretely distributed with in-plane random orientation. Thirteen kinds of laminates were studied; i.e., NWCT composites. CFRP longitudinal [0]₈, transverse [90]₁₂, off-axis [45]₁₂ and angle-ply [±45]_3S, hybrid longitudinal ([0//0//0//0/]_S, [//0//0//0//0/]_S), transverse ([90//90//90//90//90 90/]_S. [//90//90//90//90//90/]_S), off-axis ([45//45//45//45//45//45/]_S, [//45//45//45//45 45//45/]_S) and angle-ply ([+45//-45//+45//-45//+45//-45]_S, [//+45//-45//+45 -45//+45//-45]_S). The symbol "//" means that the NWCT layer is located between the CFRP layer, and the symbol "/" means a half of NWCT layer thickness. Static tensile tests of the CFRP and hybrid specimens were carried out. To estimate the stiffness of hybrid composites, the rule of mixtures (ROM) was used. The fracture surfaces of the hybrid specimens and the fracture process on the edge section were observed with a scanning electron microscope (SEM) and an optical microscope, and the failure mechanism was analyzed. The hybrid specimen seems to be effective for improving the tensile characteristics.