Investigation on the shear behaviors of carbon fiber composite sandwich panels with the X-core

In-plane shear response of an all-composite X-core sandwich panel was investigated experimentally, numerically and analytically in this paper. The shear experiments of the X-core sandwich panels with three different relative densities were performed and the delamination on the joint and web was the dominant failure mode. Finite element analysis were conducted to further investigate the large deformation and progressive failure of the X-core sandwich panels under in-plane shear loading. The numerical models can correctly simulate the initiation and extension of the delamination and the predictions for the shear response were in good agreement with experiments. A theoretical model based on a modified Reddy zig-zag laminated beams theory and a spring model for the joint were employed to forecast the shear mechanical properties. The analytical results indicated the member shear deformation and joint stiffness had significant effects on the shear modulus and had a reasonable agreement with the experimental results. •The in-plane shear properties of CFRP X-core sandwich panels are investigated experimentally, analytically and numerically.•A theoretical model based on a modified Reddy zig-zag laminated beams theory and a spring model were employed.•FE models can reasonably capture the initiation and extension of the delamination from the joint.•The CFRP X-core sandwich panels can avoid a catastrophic brittle collapse failure under shearing load.