Reversible energy absorbing meta-sandwiches by FDM 4D printing

• Published in: International journal of mechanical sciences Vol. 173; p. 105451
• Main Authors: Bodaghi, M., Serjouei, A., Zolfagharian, A., Fotouhi, M., Rahman, H., Durand, D.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.05.2020
• Subjects: 4D printing; Auxetics; Energy absorption; Hyper-elastics; Sandwich; Shape memory polymers; Sandwich; Hyper-elastics; 4D printing; Shape memory polymers; Energy absorption; Auxetics
• ISSN: 0020-7403; 1879-2162
• DOI: 10.1016/j.ijmecsci.2020.105451

•Introducing dual-material auxetic meta-sandwiches by 4D printing technology.•Arranging soft hyper-elastic polymers and elasto-plastic hard shape memory polymers.•Proposing reversible energy absorbers by leveraging instability and elasto-plasticity.•Implementing finite element methods to predict experimental observations.•Showing high capability of reversible meta-sandwiches for dissipating energy. The aim of this paper is to introduce dual-material auxetic meta-sandwiches by four-dimensional (4D) printing technology for reversible energy absorption applications. The meta-sandwiches are developed based on an understanding of hyper-elastic feature of soft polymers and elasto-plastic behaviors of shape memory polymers and cold programming derived from theory and experiments. Dual-material lattice-based meta-structures with different combinations of soft and hard components are fabricated by 4D printing fused deposition modelling technology. The feasibility and performance of reversible dual-material meta-structures are assessed experimentally and numerically. Computational models for the meta-structures are developed and verified by the experiments. Research trials show that the dual-material auxetic designs are capable of generating a range of non-linear stiffness as per the requirement of energy absorbing applications. It is found that the meta-structures with hyper-elastic and/or elasto-plastic features dissipate energy and exhibit mechanical hysteresis characterized by non-coincident compressive loading-unloading curves. Mechanical hysteresis can be achieved by leveraging elasto-plasticity and snap-through-like mechanical instability through compression. Experiments also reveal that the mechanically induced plastic deformation and dissipation processes are fully reversible by simply heating. The material-structural model, concepts and results provided in this paper are expected to be instrumental towards 4D printing tunable meta-sandwiches for reversible energy absorption applications. [Display omitted]