Assessment of 3D woven near-net-shaped I-sections for aeronautical applications: Weave design, manufacture, and mechanical properties under multiple loading conditions

The design of composite I-sections in aerostructures faces a significant challenge with conventional laminates because they are prone to delamination under out-of-plane loads. To address this issue, this study investigates the design, manufacture, and mechanical properties of 3D woven near-net-shaped composite I-sections. The study also compares their advantages with equivalent laminates and examines the influence of weave patterns on their mechanical behavior. Specimens were manufactured using the vacuum-assisted resin transfer molding technique, and quasi-static tensile, compressive, and bending tests were conducted to assess the properties of I-sections with three different weave patterns. It finds that the ultimate strength and damage tolerance of the considered design of 3D woven I-sections are better than the considered design of 2D woven laminated counterparts, and different weave patterns play a significant effect in damage mode and load-bearing capacity. In addition, using 3D woven preforms to manufacture composite I-sections also exhibits shortened production time in terms of layup and resin infusion. Highlights: The 3D woven I-sections show improved damage tolerance over 2D counterparts. The design of weave patterns affects the properties of I-section composites. Using 3D preforms to manufacture I-sections exhibits shortened production time. Design consideration is proposed for the optimal weave pattern of the I-sections.