Track brake inspired re-entrant metamaterial stabilization with ideal energy absorption

• Novel structure designed to prevent buckling of the re-entrant geometry • New metamaterial enables the creation of ideal energy absorption regions • Programmable deformation behaviour • Experimental validation and finite element simulations performed in a highly accurate environment with extensive material model characterization Many nature-inspired novel metamaterials have been proposed recently. Novel materials, however, can also be inspired by man-made inventions. In this article, we propose a novel metamaterial inspired by the tram track brake, based on the re-entrant honeycomb. As its name suggests, the novel structure—namely the brake segment–like element—prevents buckling of the re-entrant structure by preventing asymmetry. Not only can this supplemented brake segment prevent buckling, but it can also significantly improve mechanical and deformational properties. With the proper geometry of this supplemented brake segment ideal energy absorption regions can be produced. Depending on the geometric parameters of this novel addition, its initiation can be adjusted, resulting in programmable deformation behaviour. Deformation behaviour can either be intracellular buckling, re-stabilized auxeticity or, if initiation occurs late, improved buckling. Besides mechanical testing, the novel structures were subjected to finite element testing in a highly accurate environment, involving extensive material model characterization.