Mechanical properties analysis of 3D C/C braided composite opening structures under static tension

The tensile fracture of the 3D C/C braided composite structures was studied through the static tensile test and finite element simulation analysis. Three modeling structures including circularly holed, double-edge-semicircle and double- edge-V-shaped specimens were considered for the investigation. The results show that the three open structures in the tensile failure have a strong linear stress-strain relationship and locality stress concentration. At the fixing width of the C/C specimens, the tensile notched strength is not sensitive to size, but it is sensitive to the radius of the notch-tips. The linear elastic failure mechanism can not be applied to the damaged zone of the material, which suggest that a large-scale stress relaxation should exist. The size of the damaged zone increases when the radius of the notch-tips increases, while the size is insensitive to the location of the openings.