Theoretical prediction and validation of mechanical properties and damage of 3D orthogonal woven composites with different parameters

In this work, microscopic models of three-dimensional orthogonal woven composites (3DOWCs) were developed according to the actual structural relationships of yarns. By introducing a bridging model for 3DOWCs, elastic constants, tensile, compression, and shear strength of 3DOWCs with varying yarn densities were predicted and discussed by means of the established stress-strain relationships. Meanwhile, the flexural properties were also examined employing finite element models derived from the results of the bridging model predictions. The anticipated results exhibited excellent agreement with the reported experimental data. The results demonstrated that the elastic modulus (E), tensile, and compression strength, and the shear strength in the XY- and XZ-directions increased with yarn densities, while the shear modulus (G) and YZ-direction shear strength decreased. In comparison to 3DOWCs with DT/DZ=2 yarn/cm and DW=1.5 yarn/cm (small densities), the Ez, Ex, and Ey of 3DOWCs with DT/DZ=4 yarn/cm and DW=3 yarn/cm (large densities) were enhanced by 42.3%, 193.2%, and 174.1%, respectively. Meanwhile, the tensile and compression strength of 3DOWCs with large densities were also higher than those of 3DOWCs with small densities. Additionally, the variation in flexural strength was similar to that of tensile and compression strength, which increased by 41.1%. Large densities 3DOWCs with higher fiber contents experienced minor cracking during flexural loading because of their ability to maintain structural integrity, whereas stress concentration in the contact region with the indenter was the primary damage to small densities 3DOWCs.