The yarn size dependence of tensile and in-plane shear properties of three-dimensional needled textile reinforced ceramic matrix composites

The yarn size scaling of tensile and in-plane shear properties is examined for three-dimensional needled textile reinforced ceramic matrix composites (3DN CMC) fabricated by chemical vapor infiltration. The results showed that large yarn size would cause the nonwoven yarn of 3DN CMC crimp and lower composite density, resulting in decrease of tensile and in-plane shear properties. The "modified lamina modeling" was presented to predict the tensile and shear elastic moduli of 3DN CMC with different yarn size. Other two methods were also proposed to evaluate the tensile and in-plane shear strengths of 3DN CMC with different yarn size, respectively. All predicted results showed consistent well with the experimental results.