Comparative study on in-plane compression properties of 3D printed continuous carbon fiber reinforced composite honeycomb and aluminum alloy honeycomb

Additive manufacturing is a rising continuous fiber reinforced composite molding method, which has been developed and applied in many technical fields in the current research. In this investigation, a lightweight CCFR (Continuous Carbon Fiber Reinforced) composite honeycomb is proposed based on the continuous fiber additive manufacturing, and its performance under in-plane compression is presented. Through the analysis of experimental results of honeycombs with different materials, it is demonstrated that carbon fiber can not only enhance the mechanical properties, but also change the deformation characteristics of the structures. Under the loading direction X₂ (transverse direction), CCFR honeycomb, aluminum alloy honeycomb and unreinforced honeycomb (under the X₁(longitudinal direction)/X₂ load) all have multiple local failure, while the stress–strain curve presents several large fluctuations. When subjected to X₁ pressure, CCFR honeycombs have a relatively stable stress–strain curve, and the mechanical performance is more consistent with the elastic–plastic honeycomb formed by aluminum alloy material. As well as CCFR honeycomb exhibits the largest specific energy absorption when subjected to X₁ load, which is 186.58% and 596.84% higher respectively than that of pure PLA and aluminum alloy. Cone Beam Computed Tomography (CBCT) and Field Emission Scanning Electron Microscope (FESEM) are adopted to detect the test pieces, it is also found that CCFR honeycombs have no obvious local damage and brittle fracture under the pressure of X₁.