Soft-Layered Composites with Wrinkling-Activated Multi-Linear Elastic Behavior, Stress Mitigation, and Enhanced Strain Energy Storage

Abstract

<p>Soft elastomeric composite materials constituting of an elastomeric matrix with dilute concentrations of thin, relatively higher modulus interfacial layers are presented and demonstrated to exhibit enhanced strain energy storage together with a bi-/multi-linear elastic behavior and stress mitigation - all with little to no weight penalty. In this study, the governing mechanism for these features is revealed to be the activation of wrinkling of the embedded interfacial layers upon reaching a critical strain, thereby amplifying energy storage in both the matrix and the interfacial layers. Furthermore, the energy storage in the composite is substantially greater than the sum of the energy storage of the isolated material constituents. The new features of the composite material behavior can be tailored by the concentration of the interfacial layers, and the elastic properties of the elastomeric matrix and interfacial layers. The results are demonstrated and validated through analytical derivations, finite-element analysis, and experiments. The analytical expressions provide the ability to quantitatively design and predict the material performance. These soft-layered composites point to opportunities for expanding these enhancements to networked interlayers, multifunctional interlayers, and viscoelastic elastomeric matrices for viscous damping together with energy storage.</p>