Tunable Mechanical Metamaterial with Ultra Effectiveness Based on Jamming State Honeycomb Structure

Mechanical metamaterials are sorts of artificial materials that can achieve unconventional properties due to the certain structures of arraying their unit cells. Many progresses are reported so far, including negative Poisson ratio, negative compressibility transitions, ultra-stiff and ultra-light materials, and also materials with tunable mechanical responds. However, almost all the researches focused on ordered crystallized structures, and the disordered systems are lack of investigations. We generated several honeycomb structures consisting of a number of nodes and bonds that connect each nodes, referring to the jamming transitions, which are very different from the formation of crystalline solids. We have noticed these engineered cellular solids with random porosities and structures are ultra sensitive to the applied loads when some certain bonds are replaced or removed. The phenomenon permits us to tune the modulus of such disordered structures in a large range just by subtracting a small fraction of the bonds. We perform the experiments and realize these honeycombs by using springs and hinges. Thus, from both simulations and experiments, we track the steps of bonds reducing, and find some regularities to help us establish a theoretical model to clarify the mechanism.