Architected Lattices with a Topological Transition

Topological metamaterials showing two- or multistep deformation under compression provide highly tunable stress-strain responses. A contact-enabled mechanism is incorporated into lattice structures through substituting the regular struts to obtain a global multidirectional two-step deformation. The proposed mechanism is a longitudinal structure with different beams designed for bending or buckling in different stages of deformation. When axially compressed, the mechanism shows a standalone two-step response, which can be widely tuned by varying its geometric parameters. The presence of the mechanisms in different orientations allows for multidirectional functionality, which signifies the uniqueness of this method. By conducting experiments on 3D-printed samples and finite element simulations, the working principle and functionality of the mechanism and lattices in 2D and 3D are shown. It is also explored how the lattice connectivity affects the performance of the topological lattices, and concluded that high enough connectivity of a lattice to achieve stretching-dominant behavior is required for the metamaterial to achieve two-step deformation. This article develops topological metamaterials showing multidirectional two-step deformation under compression by embedding contact-enabled topological mechanisms into lattice structures. Experiments on 3D-printed 2D and 3D lattices and finite element simulations are conducted to demonstrate the working principle of the topological metamaterials. It is concluded that a high-connectivity lattice with stretching-dominant behavior is essential for the two-step deformation.image (c) 2023 WILEY-VCH GmbH

Automated summary

This article investigates topological metamaterials exhibiting multidirectional two-step deformation, achieved by embedding contact-enabled topological mechanisms into lattice structures. The working principle of the topological metamaterials is demonstrated through experiments on 3D-printed 2D and 3D lattices, revealing the necessity of high-connectivity lattices with stretching-dominant behavior for two-step deformation.