Influence of shell thickness and lattice infill on the mechanical performance of a biomimetic alligator mandible structure

Biomimetic designs that draw inspiration from structures found in nature provide a unique approach to engineering solutions and can reveal innovative concepts. The use of hollow-walled designs with porous infill provides an opportunity to achieve highly efficient structural designs. However, the experimental application of using hollow-walled designs as an approach to increase the efficiency of biomimetic structures is yet to be explored. This paper hence investigates the influence of shell thickness and lattice infill on the mechanical performance of a biomimetic structure using the example of an alligator mandible. Experimental and numerical approaches were employed to assess the mechanical properties of additively manufactured mandible structures under bending and compressive loading conditions. Finite element simulations were validated against mechanical testing and quantitative thermoelastic stress analysis (TSA). The shell thickness of the mandible was found to be more critical to the specific bending and compressive stiffness of the structure compared to the inclusion of the lattice infill. The TSA scans quantified the effect of shell thickness and infill on the unique surface stress distribution of the mandible, which increased with a reduction in shell thickness. These findings highlight the potential of hollow-walled designs as an approach to create more efficient, and optimised, biomimetic structures. This methodology can be applied to alligator mandible-like designs for load-bearing engineering applications that involve complex loading conditions, such as cantilevered bracket structures.