High-Speed 2D-Digital Image Correlation to Quantify Energy Mitigation Behaviors of Engineered Elastomeric Materials Subjected to Shock

Engineered, elastomeric material damping systems have revealed striking ability to attenuate shock loads at the macroscopic level. Reports suggest that this capability is associated with the reversible elastic buckling of internal beam constituents observed in quasistatic characterizations. Yet, the presence of buckling members induces non-affine response at the microscale, so that clear understanding of the exact energy dissipation mechanisms remains clouded. In this report, we examine a mechanical metamaterial that exhibits both microand macroscopic responses under impact loads and devise an experimental method to visualize the resulting energy dissipation mechanisms using 2D Digital Image Correlation (DIC). Without existing standards for applying 2D-DIC for studying high strain rates of absorbent, viscoelastic material structures, a novel approach for executing 2D-DIC visualization was implemented using charcoal powder. Simultaneously collected force transmission data and DIC analysis associated with the deformation of test specimens under impact loading reveal a bridge for studying the microscale interactions that culminate in macroscale deformation. To illustrate the potential of this application, this experiment was carried out on specimens with varying, but known, quasistatic loading behaviors to verify and validate discrepancies between quasi-static and dynamic loading. This process illuminates the influence of dynamic strain distribution throughout the material’s in-plane cross-section on its overall tendency to buckle uni- or bimodally, thus dissipating injected force with varying degrees of force transmission and pulse duration. With this understanding, we uncover a strategy for geometrically programming the macroscopic deformation to enhance impact mitigation properties.Haythornthwaite FoundationOwens Corning Science and TechnologyNo embargoAcademic Major: Mechanical Engineerin