Biomimicry of Combative Bovids to Revamp a Lightweight, Energy-Absorbing Lattice for High Impact Applications

Overview

This study applies biomimetic principles derived from muskox and bighorn sheep cranial anatomy to develop a lightweight, energy-absorbing lattice structure for high-impact applications. Both species exhibit remarkable resistance to traumatic brain injury despite participating in forceful head-butting behaviors, with the muskox skull enduring impacts estimated at 12,500 N through a multilayer composition of keratin, trabecular bone, and cortical bone. The bighorn sheep horncore, characterized by velar bone architecture and keratin sheaths, demonstrates substantial strain energy absorption capacity, with previous research indicating that the horncore stores three times more strain energy than the horn itself. Building on prior findings that horn-like truss lattices exhibit superior energy absorption compared to alternative lattice configurations, this work integrates muskox horn geometry with a horn-inspired flower-like lattice design to investigate the contribution of external horn structures, designated as points of impact, to overall energy absorption performance.

Methods and approach

Two distinct lattice designs were developed: one incorporating external horns to serve as points of impact and one without these features. Both designs merged the external horn shape of the muskox with a horn-inspired flower-like lattice geometry. The lattice structures were fabricated using 3D printing technology with PLA+ plastic as the material substrate. The fabricated specimens were subjected to repeated impact force testing to evaluate energy absorption characteristics and determine the functional role of the external horn structures in dissipating impact energy.

Key Findings

The lattice design incorporating external horns as points of impact absorbed 31% of the total impact energy, while the design without these features absorbed 25% of the total impact energy. The effectiveness of the points of impact was found to be material-dependent, with these structural features demonstrating functionality only when ductile materials were employed. The experimental results indicated that material properties, specifically ductility and toughness, exert a more dominant influence on energy absorption performance than structural geometry considerations.

Implications

The findings establish that while biomimetic structural features such as external points of impact can enhance energy absorption in lattice designs, their effectiveness is contingent upon material selection, particularly the use of ductile substrates. The primacy of material ductility and toughness over geometric configuration in determining energy absorption capacity suggests that optimization strategies for impact-resistant structures should prioritize material property selection alongside structural design. These results inform the development of lightweight protective systems and energy-absorbing components for applications requiring resistance to high-impact forces, while highlighting the limitations of geometry-focused biomimetic approaches when decoupled from appropriate material characteristics.