Numerical method and influencing factors of composite pyramidal truss core sandwich structures with a hole

Failure modes of composite sandwich column with pyramidal truss core containing a hole were studied through experiments aimed to study the failure mode and influencing factors of composite lattice sandwich structure with a hole under compression loads. Finite element analysis progressive damage failure mode of composite lattice sandwich structure with a hole was established based on 3D Hashin criterion and Chang-Chang stiffness degradation criterion, and the calculated results were compared with experimental ones. Based on the finite element method, the impact of the opening shape, ratio and position on its ultimate loading capacity was discussed. The result shows that when the face-sheet of lattice sandwich structure containing a hole is thinker, the main failure mode is face crushing. By contrast the results of finite element calculation and experimental ones, the maximum error of the ultimate loading capacity is about 12%, and failure position is consistent with the experimental results. When the center of the hole is in the symmetry plane parallel to the direction of the load, the compressive strength of the lattice sandwich structure has nothing to do with the opening position, mainly influenced by the opening shape and ratio. When the center of hole is in the symmetry plane perpendicular to the direction of the load, if the margin is larger than one cell size, the compression strength of the lattice sandwich structure substantially does't change, otherwise the compression strength decreases.