Bending properties and numerical analysis of nonorthogonal woven composites

The helmet shell material featuring a gradient in bending is urgently required for the next-generation integrated helmet system. However, achieving a bending gradient design for orthogonal woven composites on a 3D shell surface is a significant challenge. Here, nonorthogonal woven composites at 30 degrees, 45 degrees, and 60 degrees were fabricated, and their bending properties are discussed. Furthermore, their bending properties are compared to those of plain off-axis woven composites, which indicates that the bending linearity trend of nonorthogonal woven composites is evident. Notably, the bending strength of the 30 degrees and 60 degrees nonorthogonal woven composites is 66.9 and 67.4% higher, respectively, than that of the plain off-axis woven composites, and the bending modulus is 169.8 and 196.9% higher, respectively. Finally, a finite element analysis of the bending properties of nonorthogonal woven composites was conducted, and a stress analysis of the inner layers was also conducted. This work paves the way for designing gradient materials for helmet shells.