Bioinspired Design

Abstract

Bioinspired design involves the use of concepts observed in natural biological materials in engineering design. The hope is that the leveraging of biological materials in the engineering domain can lead to many technological innovations and novel products. This work presents the initial material characterization of kinixys erosa tortoise shell using a combination of x-ray diffraction, optical/scanning electron microscopy and micro-mechanical testing. The results were used in the analytical/computational modelling of shell structures. The potential implications or the results were then discussed to give fundamental understanding of deformation and stress responses of shell structures

Bioinspired Structures and Design

“…In this section, it is interesting to explore the layered structure of the turtle/tortoise shell (Figure 1.10) and how this contributes to the management of contact stresses in shell structures. This has been studied by Damiens et al [38] and Owoseni et al [39]. The studies of Owoseni et al [39] on Kinixys erosa tortoise reveal a layered structure that consists of an outer layer of cortical bone, a middle layer of trabecular bone, and an inner layer of cortical bone (Figure 1.10).…”

“…This has been studied by Damiens et al [38] and Owoseni et al [39]. The studies of Owoseni et al [39] on Kinixys erosa tortoise reveal a layered structure that consists of an outer layer of cortical bone, a middle layer of trabecular bone, and an inner layer of cortical bone (Figure 1.10).…”

“…Several materials in nature have layered hierarchical structures that can provide insights into the management of stresses in layered composite materials. These include bamboo [20,37], the dento-enamel junction [13,17,20,21], and turtle/tortoise shells [38,39], in which layered structures have evolved to reduce or manage the stresses that might lead to fracture during exposure to loading under different conditions. Hence, these materials will be explored in this section as potential sources of bioinspiration for the design of robust layered structures.…”

Compressive deformation and failure of trabecular structures in a turtle shell

“…The Young's moduli measured corresponding to the actual unloading segment of the load-deflection curves [34] were 13.9 ± 0.9 GPa for the external cortical bone, 12.1 ± 1.0 GPa for the internal cortical bone, and 4.0 ± 2.1 GPa for the trabecular bone. These are consistent with prior reports in the literature [1].…”

“…2a). The carapace bone exhibited a widened peak for 2h between 31°and 33°, resulting from the superposition of the highest (2 1 1) peak of hydroxyapatite (HA) at 31.61°, the second highest (3 0 0) peak at 32.72°and another prominent (1 1 2) peak at 32.22° [34][35][36]. Lower intensity peaks of HA were also detected based on the small humps between 46°and 54° [36].…”