Quasi-static and dynamic stab behavior and damage mechanisms of the spiral/laminated structure of CFRP

Abstract

Stab resistance depends on the material’s strength and stiffness. Puncture energy is absorbed mainly through fracture and friction in the damaged area. To reduce stress concentrations and diffuse impact energy, this paper proposes a spiral CFRP inspired by spiral grass. Comparison of the puncture resistance of spiral CFRP and laminated CFRP by quasi-static and dynamic puncture. After separating the puncture process into longitudinal piercing and transverse cutting, it was found that spiral CFRP had excellent cutting resistance, with a maximum cutting force 44% higher than laminated CFRP. However, the detachment of the central structure leads to weaker perforation resistance of spiral CFRP than laminated CFRP. Laminated CFRP was found to undergo internal delamination damage after perforation by microscopic characterization and finite element analysis. Spiral CFRP has a helical yarn path and the interface distribution parallel to the impact direction, resulting in a greater susceptibility to delamination damage and rapid spiral crack propagation. The damaged area of spiral CFRP is up to 416% larger than that of laminated CFRP. The structural instability also resulted in a higher penetration depth for spiral CFRP than for laminated CFRP. The composite structure provides better puncture resistance than a single structure. Due to the combined advantages of the passivation of spiral CFRP and the structural stability of laminated CFRP, Sprial/laminated CFRP has the highest puncture resistance, with a maximum puncture load of 1,467N, and is not penetrated at a puncture energy of 24J. The spiral structure incorporating crack-inducing and transverse damage resistance could offer a promising approach to developing stab-resistant materials.