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International Journal of Bioprinting Sub-regional design of the bionic bone scaffolds

Figure 1. Design procedures for the bionic bone scaffold.

previous design method did not implement the graded 2. Design and methods
distribution of the characteristic parameters, which is the
most critical design of the bionic bone scaffolds. Referring The BESO methodology was introduced to realize the
to previous studies, we propose in this work a sub- macrostructural topology in this paper. The bionic bone
regional design methodology of the bionic bone scaffolds, scaffolds were designed using the novel CAD software
©
based on the macrostructural topology and the Voronoi Rhinoceros3D (Robert McNeel & Associates, v.7.0 SR4)
tessellation. It is worth pointing out that the definition with the plugin Grasshopper™ v.1.0.0007. The flow chart in
of macrostructure in this paper is the original model for Figure 1 illustrates the procedures for modeling this bionic
BESO while the corresponding microstructure represents bone scaffold, including (a) bone defect site analysis, (b)
the FGPMs populated in the design domain. The design macrostructural topology, (c) Boolean operation according
domain is divided into sub-region A (representing the to the combined probability sphere model, (d) 3D Voronoi
BESO density region) and sub-region B (representing the tessellation based on the graded nucleating points, (e)
BESO non-density region) as the guideline for pores’ graded porosification based on the distance-to-scale coefficient
design. It is worth noting that, with a mechanical continuity mapping model, and finally (f) fabrication and implantation.
concern, the porosity and the aperture values in sub-region 2.1. Design and parametric characterization of the
B follows the distance-to-scale coefficient mapping model, bionic bone scaffolds
presenting a gradient change. Additionally, the as-designed To realize the most reasonable graded distribution, the
models were analyzed in this work through mechanical topological information of the macroscopic model is
simulation and were validated after being fabricated by the needed. Based on the axiom of the uniform strain energy
LPBF process, using the Ti-6Al-4V powder, to study the density, the maximization structural strength requires
quasi-static compressive behavior. Notably, this approach minimizing the strain energy . In this paper, the design
[37]
considers the overall problem of shape and the property variable is the unit density, and the optimization objective
control under the synergistic constraints of mechanics, is to minimize the strain energy of the macrostructure. The
biology, geometry, and LPBF process, and it delivers a mathematical model of strength optimization under the
full discussion regarding the influence of irregularity and constraint of equilibrium equation is expressed as follows:
scale coefficient on mechanical properties of the as-built
specimens. U()ρ = 1 P δ
T
i
2
This paper is divided as follows: section 2 presents the s tK.. T δ = P
design and the methodology approaches; section 3 shows n ∗ (I)
the obtained results, from a simulation and implementation ∑ V ρ − f V = 0
i
v
i
points of view, and the comparison; and the last section i=1 p ∗
concludes this work and proposes some ideas, which will E = ρ i E i
i
be implemented in future. ρ = ρ min or 1
i
Volume 9 Issue 6 (2023) 42 https://doi.org/10.36922/ijb.0222