Local impact resistance of curved sandwich panels with coaxial and concentric honeycombs

Abstract

The local impact resistance of honeycomb sandwich panels with curved and flat geometries differs due to the global stress state. In this study, curved sandwich panels with coaxial and concentric honeycombs are designed and their resistance is investigated against local impact. The numerical model is calibrated with the air cannon test results and then used to compare the performance of structures that are sandwiched by different honeycombs. The comparable study shows that the impact resistance of flat sandwich structures outperforms that of curved ones at a low impact velocity, and a small radius of curvature should be avoided when considering an enhancement of the impact resistance by curvature design. In addition, under the high-velocity impact, sandwich panels with concentric honeycombs show an improved impact resistance as compared to those with coaxial honeycombs. However, the influence of honeycomb configurations on the impact resistance is reduced as the radius of curvature increases. Using the equivalent analysis, the equivalent face sheet thickness and equivalent impact velocity of curved sandwich structures with different radii of curvature, which are compared to the flat structures that are subjected to typical impact loads, are achieved.