FINITE ELEMENT CALCULATION OF A 3-D BRAIDED COMPOSITE UNDER BALLISTIC PENETRATION AT QUASI-MICROSTRUCTURE HIERARCHY

Compared to laminated composites, three-dimensional braided composites have higher inter-laminated shear strength and fracture toughness. The impact damage tolerance of a 3-D braided composite is higher than that of the laminated composite. The 3-D braided composite was perforated by a steel core projectile. The strike velocities and residual velocities of the projectile were measured, and the failure mode of the composite under ballistic impact was also investigated. All of the works on analysis and calculation of ballistic penetration of the 3-D braided composite so far were based on continuum assumption. It is still difficult to model the 3-D braided composite under ballistic impact from actual microstructure now. A fiber inclination model for the 3-D structural reinforced composite is employed to decompose it at quasi-microstructure hierarchy. The ballistic penetration property of one of the inclined laminae is calculated with FEM code. The residual velocity of the projectile that perforated the entire 3-D braided composite is obtained from the loss of kinetic energy of the projectile. From the simulation of ballistic penetration process and comparison between numerical results and experimental results, it proves that the analysis scheme of quasi-microstructure hierarchy in this paper is valid and reasonable.