Flexural performances of fiber face-sheets/corrugated core sandwich composite structures reinforced by horizontal stiffeners

Abstract The light-weight and high-strength design concept enables sandwich composite structures (SCS) to maximize specific strength and specific energy-absorption (SEA). To this end, a horizontal stiffener is designed to reinforce the flexural performances of corrugated core SCS for the first time. To explore preferable reinforcement parameters, several stiffeners with different thicknesses, positions and numbers are designed and studied. The flexural responses of SCS are predicted by finite element simulation. The predicted load responses, damage and deformation of face-sheets and core are consistent with experimental observations. From predicted results, the SCS undergoes several stages including elastic deformation, fracture of face-sheet, initial and stable deformation of core. The core with a stiffener obviously exhibits higher SEA than that without a stiffener. Complex reinforcement mechanisms and coupling deformation between pure core and stiffener are revealed. It is found that the stiffener improves not only the EA of pure core but also the EA of face-sheets, which explains the coupling EA. Structural parameters including thickness, position and number have great effects on flexural performances of SCS. Notably, the lightest SCS with 0.25 mm thickness improves the SEA about 23.83%. The SCS with three stiffeners presents an increase in EA of 92.33% but followed by a great increase in mass. Design recommendations are finally concluded through comprehensive evaluations.