Reusability and energy absorption behavior of 4D-printed heterogeneous lattice structures based on biomass shape memory polyester

Uniform triply periodic minimal surfaces (TPMS) have been extensively used due to the good mechanical properties and energy absorption. The hybrid of lattices could combine the advantages of substructures with desirable properties. Moreover, the reusability of TPMS after external loading and the repeated energy absorption capacity are relatively unexplored. Herein, novel heterogeneous TPMS lattices composed of Gyroid and Diamond were designed and manufactured using a biomass shape memory polymer. First, a smooth transition between the adjacent substructures were achieved via structural design. Then, the external force (compression load) and thermal stimulated shape recovery cycles tests were conducted. The results showed that the heterogeneous samples exhibited multiple yielding stages and continuous energy absorption due to the synergistic effect of sub-structures. The large-deformed TPMS structures were able to recovery to the original shape under thermal stimulation, possessing a high rate of shape fixation and shape recovery (nearly 100 %). After experiencing several cold programming-shape recovery cycles, the total energies of heterogeneous structures did not sharply decrease and no obvious dam -age was detected by micro-CT, demonstrating a favorable reusability and repeated energy absorption capacity. Therefore, the development of 4D-printed heterogeneous lattice structures have great potentials in smart protective equipment and lightweight smart components.(c) 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).