| Fiber-reinforced composite laminates and fiber-metal laminates (FMLs)with excellent specific strength, high specific modulus, well designable abilityand simple preparation as well as great fatigue resistance, are widely used inaerospace, automotive and marine, transportation and protective equipment.This paper experimentally and numerically investigated the dynamicresponse of Kevlar/epoxy laminates and Aramid reinforced aluminum laminates(ARALL) under impact loading. Based on the blunt projectile impact test ofwoven Kevlar/epoxy laminates, the deformation and failure modes of thecomposite laminates subjected to impact loading were analyzed. Experimentalresults showed the deformation and failure modes of composite laminates weremainly grouped in: the global elastic deformation; global plastic deformationwith local embedded failure on the front surface; delaminated failure with fiberstension fracture on the back surface. The finite element software LS-DYNA971was employed to analyze the dynamic response of the woven Kevlar/Epoxycomposite laminates subject to impact loading. The embedded failure shape onthe bullet impact region was circular, while failure shape on the back of the platewas square. Numerical simulation results show a great agreement with experimental results. The numerical simulation is focused on studying the effectsof the number of layers on the dynamic response of the structure. Withthe optimum of fiber layers, we can effectively reduce the permanentdeflection, increase the energy absorption efficiency and improve the impactresistance performance of structure within a certain range of impulse.Based on the impact test using hemispherical head projectile, the failuremodes of ARALL under different impact impulses were analyzed. The testpointed out: the failure region of specimens was grouped into clamped region,global deformation region and local deformation/failure region; Two modes of“Diagonal Tear” and “Cross Tear” were observed on the back of the plate; moresevere delamination and matrix cracking developed on the back face comparedto front face. Then a Multi-scale model was established in HYPERMESH andthen analyzed in LS-DYNA971. A clearly deformation and failure modes, suchas fibers tension fracture, matrix cracking, inter-layer slippage, delamination andthe global elastic deformation, could be observe through the Multi-scale model.This method, combining integrated model with fiber scale model, with a goodaccuracy when reducing the number of the grid, provides a new method for thenumerical simulation of composite structures. |
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