Damage Resistance of Honeycomb Sandwich Composites under Low-Energy Impact

Due to advantages of light-weight, high-strength, and superior energy absorption, honeycomb sandwich composites (HSC) are widely used in the aerospace industry. However, HSC are prone to damage from low-energy impacts, posing a threat to the overall safety of components. This paper presents a comprehensive analysis of the damage resistance of the HSC synergistic approach of experimental validation and finite element (FE) simulation. A drop hammer impact experiment was conducted on specimens with varying upper and lower panels thicknesses, utilizing Digital Image Correlation (DIC) technology to monitor the deformation and strain of the impacted panels. The study identified the upper panel as the initial failure point, characterized by matrix cracking, fiber fracture, and interlayer delamination, with the honeycomb core primarily experiencing crushing damage. A critical impact energy threshold of 40 J was established for upper panel penetration, with lower panel damage becoming evident at energies exceeding 80 J. The quantity of panel layers significantly enhances the damage resistance of the structure. Investigated the damage characteristics of the lower panel under impact load. An FE model was meticulously constructed, incorporating the Hashin failure criterion and damage evolution, and was calibrated to reflect the experimental conditions precisely. The simulation results were found to be in excellent agreement with experimental data, with discrepancies within a 5% margin, thereby validating the predictive capabilities of FE model. The interlayer damage of finite element model, leading to the identification of delamination characteristics. This insight is advantageous for the analysis of the residual strength. Subsequent analysis explored the impact of various design parameters on damage resistance, providing valuable insights for the structural design and material selection in aerospace applications.