Mechanical Properties of Pyramidal Lattice Sandwich CFRP Composites to Flat and Bending Loads

In this study, by rearranging the typical pyramid lattice structure of carbon fibre reinforced polymer composites to obtain a small node distance and simplify the fabrication procedure, a new type of pyramid lattice structure is designed and fabricated using the snap-fit method. The flatwise compression and bending properties of the new pyramid lattice structure are studied experimentally. The results show that the compression failure mode of the lattice structure is truss fracture, while the bending failure mode is truss fracture and debonding between face sheets and cores. The damage distribution of the fibre and matrix in the lattice structure core is obtained via a finite element simulation, and it is found that there are differences in the ply damage with different fibre directions. In addition, the influence of the core truss length and layering direction on compression and bending properties of the structure are analysed using a finite element simulation.