Keywords: failure mode, finite element, glass fibre, impact, laminates, projectile.

Laminated fibre-reinforced composite materials, especially fibre metal laminates (FMLs), are increasingly used in the field of aircraft and aerospace industries due to their low density, high specific strength and stiffness. Such laminated structures are subjected to different loading conditions during their service life. For example, the horizontal stabilizer of a commercial plane, made of laminated composites, may be impacted by a projectile or by hailstones during flight. Unfortunately, experimental work carried out to determine the failure characteristics of newly designed composites structures can always be costly and time consuming. To reduce destructive tests and enhance time and cost efficiency, numerical simulations are widely used to predict structural characteristics. Finite element (FE) modelling is an effective tool to model failure mechanisms and energy absorption of laminated composite structures under static and dynamic (impact) loading. In FMLs, failure of the metallic layer can be relatively easily simulated using FE modelling. However, modelling failure of the fibre ply still remains a challenging task. Impact damage modes of fibre ply usually consists of local permanent deformations, fibre breakage, matrix cracking, and delamination. This damage will cause considerable reduction in structural stiffness, leading to growth of the damage and final fracture. The fibre ply under impact can be fractured or damaged initially that is not visible to the naked eye and may spread beyond the impact zone. The speed of the reduction of the residual properties by these cracks under alternating stress is an additional hazard. Therefore failure of fibre ply is far more complex than that of the metal layers in FMLs, which is still a challenge to researchers today.

In this paper, finite element models using ABAQUS/Explicit were developed to simulate the dynamic perforation of a projectile through glass fibre laminates panels. Glass fibre was treated as an isotropic material with both shear and tensile failure criteria. A series of low-velocity impact tests were carried out on 4-ply, 8-ply and 16-ply glass fibre laminates panels. Reasonably good correlation was obtained between the simulated and experimental load-displacement relationships. In addition the predicted failure modes of the panels were compared with the experimentally obtained failed modes with reasonable correlation. The models developed may be further used to simulate fibre metal laminates subjected to a projectile impact.

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