Modeling Low-Velocity Impact Damage of Composite Sandwich Panels

Analytical solutions for the low-velocity impact damage of composite sandwich panels are found by considering systems of discrete masses, springs and constant-force dashpots. Equivalent spring and dashpot forces for the sandwich panel are derived from the static load-indentation response and adjusted with dynamic material properties of the facesheet and core. Predictions of the maximum impact force are about 15% higher than experimental values, which is the same order of accuracy that is obtained from the static load-indentation analysis. Damage initiation due to tensile failure by hemispherical-nose shape projectiles and shear failure by blunt projectiles are examined. Predicted tensile and shear failure loads are about 20% higher than experimental results.