The role of the hyoid apparatuses of woodpeckers for energy dissipation

In order to examine the role of the hyoid apparatuses of woodpeckers with respect to energy mitigation, we investigated its unique geometry using FEA (finite element analysis). It is believed that the hyoid apparatus' role is to aid in protecting the woodpecker's brain from damage by dissipating stress waves due to impact while pecking. The woodpecker's hyoid apparatus has a unique structure compared to other birds' hyoid apparatus as it starts at the tip of the beak, which is the tongue, surrounds the woodpeckers' skull, and ends at the root of the upper beak. The hyoid apparatus has cartilage at its core, and the cartilage is surrounded by muscle. In this study, we constructed the model of the hyoid apparatus using ABAQUS-explicit FEA software, applied a blast pressure, and measured the change in pressures along various locations on the apparatus. The results showed that the impending longitudinal stress wave was decreased by 97.5% at the free end of the forked geometry, while the shear stress increased 74.7% at the same free end. We believe that this is due to the spiral geometry of the hyoid apparatus. The analysis of the woodpecker's hyoid apparatus provides additional insight into energy dissipation from the perspective of novel biological structural materials. Our focus is to develop protective gear for soldiers and athletes based on such designs in nature. Keywords: Woodpecker; Hyoid; Energy dissipation; Finite element analysis
Introduction A woodpecker has a unique structure of a hyoid apparatus compared to the hyoid apparatus of other birds'. The hyoid apparatus starts at the beak tip, surrounds the skull, [...]