Compression behavior of the 4D printed reentrant honeycomb: Experiment and finite element analysis

Shape memory polymer (SMP) is a kind of intelligent material that produces shape changes under external stimulus conditions. 4D printing is a comprehensive technology based on deformable materials and 3D printing. Based on 4D printing technology of SMP, this paper presents a smart reentrant honeycomb that is shape reconfigurable, self-deployable, mechanically tunable and reusable. The shape programming and the process of self-deployment of the smart honeycomb are demonstrated and analyzed, and its switching stiffness and energy absorption function are characterized quantitatively and qualitatively. Based on the analysis of the honeycomb parameters on the mechanical behavior, unidirectional and bidirectional gradient honeycombs are obtained, and the controllability and selectivity of any local deformation and stress-strain curves are realized. Two of honeycombs can achieve the orderly regulation of trapezoidal and concave deformation modes, respectively. The gradient design can achieve continuous adjustment of the stress-strain curve in the compression process. This kind of intelligent honeycomb with novel deformation effect has a good application prospect in applications such as morphing wings, soft robots, and mechanical vibration damping devices.