Quasi-static mechanical behavior of 2.5D woven variable thickness composites

Many special-shaped structural parts have begun to be prepared in aerospace and other fields using 2.5D woven composites. Therefore, two kinds of 2.5D woven variable-thickness composites are designed by reducing the number of yarn layers, called outer reduction yarn woven composites (ORYWC) and inner reduction yarn woven composites (IRYWC). Both variable thickness regions comprise five independent parts, each occupying one or two layers of yarn reduction. In addition, the microstructure of ORYWC and IRYWC is measured using X-ray computed tomography, and the mechanism of geometric deformation during weaving and molding is discussed. Finally, the quasi-static tensile test is conducted to compare and analyze the longitudinal stiffness, tensile strength, and damage mechanism of ORYWC and IRYWC. The results show that the longitudinal stiffness of the five parts of the two structures maintains little difference. The average stiffness and tensile strength of IRYWC decrease by 4.82% and 10.65% compared with ORYWC.