In-plane compression properties of 3D printed continuous carbon fiber circular improved honeycomb

To improve the compression resistance and energy absorption performance of circular honeycomb (CH), two improved honeycomb, single enhanced circular honeycomb (SEH) and double enhanced circular honeycomb (DEH) were designed on the basis of CH structure, and leaf shaped supports were added horizontally and vertically. Using carbon fiber (CF) as reinforcement and polylactic acid (PLA) as matrix, continuous fiber 3D printing technology was used to manufacture test parts, and the forming path of CF bundle inside the structure was designed, PLA control group was set. The in-plane compression properties, energy absorption characteristics and deformation failure modes of the honeycomb structures were investigated by quasi-static compression tests. The results show that the specific energy absorption (SEA) of CF enhanced DEH-CF is improved by 167.63% compared with CH-CF. The SEA are increased by 43.37%, 63.17% and 161.58% and mean crushing force are increased by 51.72%, 61.81% and 96.09% compared with the PLA control group, respectively. The results indicate that the fiber path planning inside the CF reinforced structure would affect the stiffness and deformation behavior of the structure. The dynamic Poisson's ratio of the DEH-CF using the "strut integrated molding path" during compression remains 33.36% lower than that of the PLA control group.