Effective performance analysis of stiffened honeycomb sandwich panels using VAM-based equivalent model

The stiffened honeycomb sandwich panel (stiffened HSP) is an improved honeycomb structure by adding the stiffeners into the traditional honeycomb core to enhance the structural performance. The novelty of this work is that the constitutive parameters of the panel are obtained by asymptotical analysis of the strain energy stored in the periodic unit cell, and a 2D dimensional reduced model (2D-DRM) is constructed on this basis. The efficiency and accuracy of 2D-DRM are verified by comparing with the results of 3D direct numerical simulations (3D-DNS) under different working conditions (including static displacement, local field distribution, free vibration and global buckling). In addition, the effects of the structural parameters of the stiffened HSP and the layup configuration of the facesheet on the equivalent stiffness, specific stiffness as well as static and dynamic performance are systematically studied. The results reveal that the facesheet thickness-to-core height ratio had the greatest influence on the buckling load, while the side length-to-height ratio of core cell had the greatest influence on the fundamental frequency. Compare with the traditional and vertical stiffened HSPs, the horizontal stiffened HSP has larger buckling load and lower natural frequency.