Uncovering a high-performance bio-mimetic cellular structure from trabecular bone

Abstract

the complex cellular structure of trabecular bone possesses lightweight and superior energy absorption capabilities. By mimicking this novel high-performance structure, engineered cellular structures can be advanced into a new generation of protective systems. the goal of this research is to develop an analytical framework for predicting the critical buckling load, Young's modulus and energy absorption of a 3D printed bone-like cellular structure. This is achieved by conducting extensive analytical simulations of the bone-inspired unit cell in parallel to traverse every possible combination of its key design parameters. the analytical framework is validated using experimental data and used to evolve the most optimal cellular structure, with the maximum energy absorption as the key performance criterion. the design charts developed in this work can be used to guide the development of a futuristic engineered cellular structure with superior performance and protective capabilities against extreme loads. Natural and man-made hazards such as blast 1,2 and impact 3,4 have claimed millions of lives and caused significant damage to structures. Engineered cellular structures are at the forefront of innovative research for extreme loading applications (e.g., protective structures and crashworthiness), due to their lightweight and superior energy absorption capabilities 5,6. There is significant potential to advance these structures into a new generation of futuristic protective systems by mimicking cellular architectures found in nature 7-9. In particular, bone has optimised its intricate structure through complex evolutionary processes to minimise weight, enhance mobility and meet the cyclic loading demands of the human body 9-12. It has long been speculated by researchers that the key to the excellent mechanical properties of bone is hidden in the structural features of its well-organised cellular core, which is composed of organised networks of interconnected trabeculae 13,14. Although trabecular bone is not primarily designed to absorb energy, it has been shown to possess unique structural characteristics that facilitate excellent energy absorption 15-17. Despite that other biological cellular structures such as beetle elytra 7 and porcupine quills 15,18,19 have been reported to exhibit lightweight, buckling resilience and energy absorption characteristics through mechanical testing, investigations on biomimetic cellular structures for energy absorption applications are generally quite limited. Ghazlan et al. 20 investigated a cellular structure inspired by trabecular bone under compression and demonstrated its high energy absorption over hexagonal and re-entrant structures. Zhang et al. 7 fabricated a sandwich plate inspired by beetle elytra and demonstrated marked improvements in energy absorption over a traditional honeycomb structure under compression. Du et al. 21 also fabricated a lattice structure inspired by beetle elytra and reported a high energy absorption and bearing force under compression. Conversely, stu...

Bio-inspired 3D-printed lattice structures for energy absorption applications: A review

“…Ghazlan et al 215 devised an analytical framework for estimating the critical buckling stress, Young's modulus, and energy absorption of a 3D-printed bone-like cellular structure inspired by trabecular bone based on the Voronoi diagram as shown in Figure 29, with the results confirmed by compressive test data. The tie lengths and sub-cell angles in the unit cell were shown to have a prominent impact on obtaining the greatest energy absorption.…”

“…Figure29. Development of optimized 3D-printed bone-like structure from a trabecular bone cellular structure 215. …”

Automated simulation techniques for uncovering high-performance bioinspired cellular structures under blast loads

“…A finite element model of the baseline bone-like structure is illustrated in Figure 2. This baseline structure was selected based on our previous work, which demonstrated its high energy absorption capacity relative to re-entrant and hexagonal geometries [34]. Referring to Figure 1(b) and (d), the baseline unit cell design parameters are W=H=20normal normalmm, t=30normal normalmm, tw=2normal normalmm, α=63.43°,β=25°,γ=41.14°, lut=10normal normalmm and llt=5normal normalmm.…”

“…The main limitation of these structures is that they are built from a limited set of parameters, which reduces the design space considerably. Following these observations, a bioinspired cellular structure based on trabecular bone was developed in our recent work (Figure 1(a) to (c)) [22,34], with the goal of evolving a structure with better performance than current engineered cellular solids. To this end, several design parameters were identified from the complex network of plate-like trabeculae (Figure 1(d)) [35–37], namely the cell angles (α,β,γ) and tie lengths (lut,llt).…”

“…(a) Femoral bone; (b) Bone-inspired cellular structure; (c) Cross-sectional view; and (d) Unit cell with identified design parameters [34]. …”