Impact and Energy Absorption with Sticky Crumpled Matter

A 2D sheet, when confined to a smaller volume, can transform into a complex, disordered structure. This crumpled state exhibits mechanical properties that differ significantly from those of the original sheet, notably displaying high rigidity despite being predominantly composed of air. Crumpled materials are therefore highly effective for impact absorption, as evidenced by their use in automotive crumple zones. Here, the impact response of sticky crumpled matter is investigated (crumpled sheets of polydimethylsiloxane (PDMS)) using force measurements and high‐speed photography. Results are compared with several control systems. Additionally, coarse‐grained molecular dynamics simulations are performed to further explore the impacting behavior of crumpled materials across varying crumple densities. These findings reveal that sticky crumpled sheets exhibit the most plastic collisions (in the sense that they are characterized by greater momentum change and energy dissipation compared to other geometries). Nonstick solid PDMS demonstrates the most elastic response. Importantly, crumpled materials record the lowest peak force during impact, underscoring their effectiveness in reducing transmitted forces. The combination of lightweight construction and efficient energy absorption makes sticky crumples an attractive option for impact mitigation.