Impact testing of structural biological materials

Structural biological materials must be highly impact resistant, as appendages such as antlers and horns must sustain repeated, seasonal impact loads. Determining the impact damage progression along with the impact strength is very important for understanding how nature has optimized the structure and properties of biological materials in order to guide the design of superior bio-inspired synthetic materials. A drop weight test tower based on standards for testing fiber-reinforced polymer matrix composites was designed and fabricated to accommodate the small size of biological materials. The materials tested were divided into two groups: non-mineralized and mineralized. The former demonstrated the highest impact strength and showed strong dependence on water content, while the latter were relatively brittle and demonstrated no dependence on water content. Delamination was the most common damage mode observed for all biological materials tested.