Scaling Effects in Composite Elastogranular Materials*

Composite elastogranular materials combine the characteristics of their constituents, resulting in interesting and distinct mechanical properties. In this study, the effect of scale on the mechanical properties of composite string-rock materials comprised of elastic fibers embedded in a granular rock matrix is investigated. An experimental study is carried out to explore whether the relative global size of a composite elastogranular medium affects its bulk mechanical properties. In particular, the stiffness, strength and ratcheting-like behavior of string-rock composite is investigated for a cylindrical form. The stiffness of composite string-rock columns is shown to be scale-independent while the strength and compaction are observed to be driven by the scale.