Design and Fabrication of Carbon Fiber Polylactic Acid Composite Metamaterial for Programmable Mechanical Response

Abstract The current study is based on lattice metamaterials that can achieve a programmable mechanical response. A novel approach to decomposing a surface of a lattice into a re‐entrant structure is used to design Decomposed Surface Lattice Metamaterials (DSLMs), which are manufactured using 3D printing of short carbon fiber/polylactic acid (sCF/PLA). The DSLMs are characterized from both directions under static loading. The correlation between mechanical response and the displacement rate along the wall thickness effect, expressed as a relative volume fraction, is determined. DSLM successfully tunes the mechanical response. The Longitudinal direction of DSLM exhibits a dual modulus nature, while the Transverse direction is highly elastic. The crashworthiness index is successfully programmed to achieve the highest energy absorption of 2201 kJ m − 3 and a plateau stress of 4 MPa in the Transverse direction. A nonlinear average Poisson's ratio of 0.02 is achieved from the same sCF/PLA due to the metamaterial's topology. A positive strain rate sensitivity is observed for both directions. The stretch‐dominated deformation behavior is predicted by fitting the Gibson‐Ashby model. Overall, the Transverse direction of sCF/PLA DSLM can be applied to supporting structures and frames, while the Longitudinal direction is recommended for applications in structural sensors.