Dramatic Mechanical Response of Polymer-metal Inclusions Based Metamaterials

A periodic lattice of metal sphere (steel ball) is arranged in polydimethylsiloxane (PDMS) polymer matrix in multidimensional architecture. At multiple strains there is gradual increases in both the stress and energy absorption capability. Three-dimensional architecture demonstrated maximum loading capacity retaining its elastic behaviour. An enhancement of ~ 50% in absorption capability and stress at 40% strain is recorded as compared to one and two-dimensional architectures. The three-dimensional architecture also showed strain rate independent highly reversible behaviour for 1000 compression cycles at 30% strains and exhibit excellent mechanical stability. However, a dramatic drop in stress by ~ 100% was observed at higher strain (> 50%) in three-dimensional architecture as compared to other metamaterials. Point contacts between multiple disjoint steel balls, which form a periodic chain like structure play the key role in achieving enhanced strength and energy absorption and have importance in numerous mechanical applications where high strength and energy absorption are the prime requirement.