Energy absorbent natural materials and bioinspired design strategies: A review

Some of the most remarkable materials in terms of energy absorption and impact resistance are not found through human processing but in nature. Solutions to the continuing problems of improved composite technologies may lie in replicating naturally occurring systems. In this review, we examine several mammalian structural materials: bones (bovine femur and elk antler), teeth and tusks from various taxa, horns from the desert big horn sheep, and equine hooves. We establish the relationships between structural and mechanical properties for these materials, with an emphasis on energy absorption mechanisms. We also identify the energy absorbing strategies utilized in these materials. Implementation of these bioinspired design strategies can serve as a basis for the design of new energy absorbent synthetic composite materials. Synthetic constituent materials arranged according to the principles outlined in this work will achieve the same synergistic effects as nature and no longer be confined to the limitations imposed by a mixture law.