High-Velocity Impact Response of Titanium/Composite Laminates

Fiber metal laminates (FMLs) comprise thin metallic layers alternately bonded to fiber-reinforced composite layers. FML layups consisting of glass fiber/epoxy layers and titanium alloy Ti-6Al-4V sheets are considered, exhibiting identical overall metal layer thickness. The high-velocity impact behavior of FMLs at discrete energy levels ahead of the first composite failure is predicted analytically using mass-spring organization. The results indicate that a higher, intermediate, and lower maximum deflection, energy absorption, velocity, and contact duration are shown by FMLs 4/3-0.3, 3/2-0.3(O), 3/2-0.4, and 2/1-0.6, separately, and vice versa for maximum contact force. The FMLs with membrane and bending energies and membrane energy only seem to exhibit comparable behaviors, implying the leading contribution of membrane energy over bending energy. Moreover, the predicted out-of-plane deformation history of comparable aluminum-based FMLs with membrane energy alone at 30 J better fits the experiments than FMLs with membrane and bending energies, validating the analytical model. Furthermore, the projected maximum deflection, maximum velocity, and energy absorption of aluminum-based FMLs at 30 J, 45 J, 60 J, and 75 J energies are in good agreement with the experiments.