Tensile loading/unloading stress-strain behavior of 2D-SiC/SiC composites

In order to study the tensile damage behavior and the mechanical properties under low frequency cyclic loading of domestic 2D-SiC/SiC composites, their tensile loading/unloading behavior was investigated through experiments and a micromechanical approach. The stress-strain relationship of unidirectional continuous fiber reinforced ceramic matrix composites during loading, unloading and reloading was obtained by constructing a micromechanical model. The relationship between the number of matrix cracks and stress, and failure criterion of composites were obtained according to a fracture statistical method. Through stress changing, the model was applied to domestic 2D woven SiC/SiC composites. For monotonically tensile specimen, matrix Weibull modulus and interfacial shear resistance were gotten by using the orthogonal experiment and the least square method. Fiber Weibull modulus was obtained by making the failure strength of the predicted curve in good agreement with the experimental curve. The tensile loading/unloading stress-strain curve of 2D-SiC/SiC composites obtained with these parameters is in good agreement with the experimental result. The matrix cracking process associated with monotonic tension of 2D-SiC/SiC composites was also produced using Matlab. The results reveal that the matrix cracks are well-distributed when composites failure. The number of matrix cracks is monotone increasing with the raising stress, but it does not appear a platform, which is noted that matrix cracks have not been saturated when composites failure.