Study on tensile and compressive properties and size effect of 3D fine woven punctured C/C composites

By means of macroscopic tensile and compressive tests of 3D fine woven punctured C/C composites along Z and XY directions, the failure pattern and fracture morphology of the samples under different loads and geometric sizes were observed. The correlation among different failure mechanisms, mechanical properties of the material and geometric sizes of the samples under tensile and compressive load was obtained. The results show that the failure surface of the samples is flat along Z-directional tension and stepped along XY-directional tension. Failure modes of the samples under compressive load along Z or XY direction present 45° shear fracture. Change tendency of compressive strength with geometric sizes of the samples along Z and XY directions is the same, but compressive strength of the samples along Z direction changes more obviously than that along XY direction. The results can provide the reference for the stiffness and strength prediction as well as establishment of strength criterion for 3D fine woven punctured C/C composites.