Temperature-dependent mechanical response of 4D printed composite lattice structures reinforced by continuous fiber

Abstract

Four-dimensional (4D) printing endows three-dimensional (3D) objects with structural customizability and functional tunability, which offers the potential to manufacture advanced equipment and devices for specific structural or functional requirements. Here, we investigated the temperature-dependent mechanical and shape memory properties of 4D printed continuous fiber reinforced composite horseshoe lattice structures (CFRCHLSs). Rectangular modified CFRCHLSs with diverse cell configurations were designed and prepared by fiber/matrix co-extrusion process utilizing continuous fibers and shape memory polymer (SMP). Isothermal compression experiments and thermo-mechanical cycle experiments were conducted to investigate the temperature-dependent mechanical properties and thermally-induced active deformation capabilities of 4D printed CFRCHLSs. The results indicate that 4D printed CFRCHLSs possess temperature-dependent equivalent stiffness and peak load, and exhibit shape recovery capabilities affected by geometric configuration. Furthermore, multi-step relaxation experiments were carried out, which revealed the relaxation phenomenon of 4D printed CFRCHLSs at continuous multiple displacements. This work provides guidance for structural design, integrated preparation and characterization of thermodynamic properties of fiber reinforced composite lightweight structures with intelligent deformation behavior.