Analytical, experimental and numerical Investigation of Sandwich Panels made of Honeycomb Core subjected projectile impact

In this paper, ballistic impact on sandwich panel with composite face sheet made of Glass/Epoxy and aluminum honeycomb core has been studied. The solution is derived from a wave propagation model. At first both analytical and numerical solutions were clarified and their results were compared with experimental results. Some deformation patterns, failure modes and energy absorption mechanisms were identified by observation, such as: dynamic movement of the target, stretching, bending deformation, delamination, debonding, shear fracture honeycomb, tensile fracture of Glass/Epoxy and plug and petal formation in composite facings. The solution involves a four-stage and effective masses of the face sheets and core as the shock waves travel through sandwich panel are derived using Lagrangian mechanics. The resulting non-linear differential equation of motion was solved considering the local damage effects and corresponding energy absorptions. Also numerical model, analysis of the penetration process was performed by a nonlinear explicit finite element code, LSDYNA. The results of analytical solution and numerical simulation are compared with experimental tests. Ballistic impact tests is carried out on the samples by flat-ended projectile with 8/5 gr mass and 10 mm diameter in difference velocities.