Damage Assessments of Ballistic Impact Behaviors of GLARE 5 (3/2) Beams with Various Stacking Sequences

Fiber-metal laminated beams of GLARE 5 (3/2) lay-up configuration of dimensions: 254×25.4mm (10″×1″) with various stacking sequences were impacted by a 0.22 caliber bullet shaped projectile using a high-speed gas gun. The effect of stacking sequence was considered on FMLs with unidirectional [04°], unidirectional [904°], cross-ply [0°/90°]s and quasi-isotropic [0°/±45°/90°] lay-up orientations. Optical imaging and mechanical sectioning techniques were used to assess the impact damages. The results showed that the failure pattern was changed by altering the specimen stacking sequences. A visible longitudinal crack along the 0° fiber direction was observed for the unidirectional [04°] specimen. Subjected to the ballistic impact, damage development in the unidirectional [904°] FMLs caused the specimens to split into two halves. A Phantom V710 high-speed camera was used to monitor the crack propagation and damage growth on the backside of the specimens with unidirectional [04°] and cross-ply [0°/90°]s lay-up sequences. In particular, it was illustrated experimentally that a small circular region of damage was created on the non-impacted side of the specimens. In addition, for the unidirectional specimen, the damage progressed as a lip-shaped zone; whereas, it advanced as a diamond-shaped contour for the cross-ply specimen. The 3D dynamic nonlinear finite element (FE) code, LS-DYNA, was used to validate the experimental results. The finite element results were compared to those obtained experimentally. Good agreement between the experimental and FE result was obtained.