Compressive behavior of a turtle’s shell: Experiment, modeling, and simulation

The turtle’s shell acts as a protective armor for the animal. By analyzing a turtle shell via finite element analysis, one can obtain the strength and stiffness attributes to help design man-made armor. As such, finite element analysis was performed on a Terrapene carolina box turtle shell. Experimental data from compression tests were generated to provide insight into the scute through-thickness behavior of the turtle shell. Three regimes can be classified in terms of constitutive modeling: linear elastic, perfectly inelastic, and densification regions, where hardening occurs. For each regime, we developed a model that comprises elasticity and densification theory for porous materials and obtained all the material parameters by correlating the model with experimental data. The different constitutive responses arise as the deformation proceeded through three distinctive layers of the turtle shell carapace. Overall, the phenomenological stress–strain behavior is similar to that of metallic foams.

► Experiments, modeling, and simulation were performed on a box turtle shell. ► Experimental data provided insight into the through-thickness behavior of turtle scute. ► A model comprising elasticity and densification theory was developed. ► Finite element analyses were performed to understand structure–property relations. ► The simulation results showed good agreement between experiments and simulations.