Animal bone structure analysis aids materials development

A team from Imperial College’s bio-engineering department used X-ray microtomography to investigate how, for example, an elephant’s femur is able to maintain tensile strength and rigidity without adding extra weight.

The key lies in a network of trabecula (Latin for ‘small beam’), which form specialised tissues at the ends of load-bearing bones, where they act as mechanical struts.

Prior to the study it was not known if, or how, the geometry of trabeculae varied, or scaled up, depending on the size of the animal.

The team found that while the overall amount of bone per unit volume stayed roughly constant, the trabeculae in larger animals were thicker, further apart and less numerous. This seems to allow animals such as elephants to support their heavier load without the need for thicker and denser bones — saving valuable energy in the process.

‘We can learn a lot from nature, such as how nature develops these strong, lightweight structures. We could adopt this in design — it could inform how people develop structural foams,’ said project investigator Dr Sandra Shefelbine of Imperial.