Full‐Field Analyses of Density‐Graded Elastomeric Foams Under Quasistatic and Impact Loadings

Abstract

Density‐graded elastomeric foams are emerging as effective protective structures to guard humans against mechanical loading. This research investigates the deformation of ungraded and graded foams under quasi‐static and impact scenarios using digital image correlation (DIC). The graded samples were assembled using two interfacing strategies (seamless and adhered), leveraging the adhesiveness of the foam slurry and bulk polyurea, respectively. Deformation mechanisms, including the effect of the interface type on strain transduction and localization in density‐graded structures, are imperative for improving the impact efficacy of protective paddings. Cuboid foam plugs were subjected to quasi‐static and impact loading while recording the corresponding deformation for DIC analysis. The DIC results were separated into three case studies based on the number of layers (1, 2, and 3). The interface effect on the overall mechanical performance of polyurea foam was revealed from the bilayer, mono‐density samples, showing drastic differences between the deformations within each layer. Seamless interface samples exhibited greater compliance than their adhered counterparts in the bilayer density‐graded configurations. Trilayer‐graded foams broadened strain‐time history, extended the impact duration, and reduced strains. This research substantiates the importance of interfacing and gradation strategies on the mechanical response of elastomeric foams as a function of strain rate.This article is protected by copyright. All rights reserved.

Additive Manufacturing and Mechanics of Mathematically-generated Meta-structures

“…Most available solutions from this research vector can be summarized in terms of novel materials and structure. However, the approach to developing protective padding neglects the effect of rotational acceleration and deceleration of the brain matter during and after impact with projectiles at low and moderate speeds [7][8][9]. The manifestation of this critical shortcoming is apodictic in most standard and laboratory testing approaches, relying heavily on the mechanical behavior of protective padding to linear acceleration loading scenarios.…”