Correlating multi-scale structure characteristics to mechanical behavior of Caprinae horn sheaths

Horns are used by Bovidae animals for intraspecific combat; as such they are among Nature's toughest materials that require resistance to extreme loads. As a typical subfamily among Bovidae, Caprinae own light-wight horn with balanced strength and toughness. However, their structure and the salient mechanisms that underlie their mechanical behavior remain uncertain. This work clarifies the effect of multi-scale structure characteristics on mechanical behaviors of horn sheath by comparing Cashmere goat, White goat and Black sheep. With the methods of fractographic observations, conformational analysis, acoustic emission and finite element methods. Conformation of keratin and strength of fibre were proposed to influence the tensile/flexural performance a lot under both dried and hydrated condition. The corrugated lamellae structure was assumed to promote crack deflection and enhance dried samples, which showed more advantageous for applications of flexural loading. It is hard to impute the difference of mechanics to any one factor, and the synergism of multi-scale mechanisms is important to mechanical properties in Caprinae horn sheath. This research is expected to further encourage the horn-inspired design of secondary load-carrying lightweight composites.