Compression–compression fatigue behaviour of gyroid-type triply periodic minimal surface porous structures fabricated by selective laser melting

With the increasing application of orthopedic scaffolds, a dramatically increasing number of requirements for scaffolds are precise The porous structure has been a fundamental design in the bone tissue engineering or orthopedic clinics because of its low Young's modulus, high compressive strength, and abundant cell accommodation space The porous structure manufactured by additive manufacturing (AM) technology has controllable pore size, pore shape, and porosity The single unit can be designed and arrayed with AM, which brings controllable pore characteristics and mechanical properties This paper presents the current status of porous designs in AM technology The porous structures are stated from the cellular structure and the whole structure In the aspect of the cellular structure, non-parametric design and parametric design are discussed here according to whether the algorithm generates the structure or not The non-parametric design comprises the diamond, the body-centered cubic, and the polyhedral structure, etc The Voronoi, the Triply Periodic Minimal Surface, and other parametric designs are mainly discussed in parametric design In the discussion of cellular structures, we emphasize the design, and the resulting biomechanical and biological effects caused by designs In the aspect of the whole structure, the recent experimental researches are reviewed on uniform design, layered gradient design, and layered gradient design based on topological optimization, etc These parts are summarized because of the development of technology and the demand for mechanics or bone growth Finally, the challenges faced by the porous designs and prospects of porous structure in orthopedics are proposed in this paper

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Porous Scaffold Design for Additive Manufacturing in Orthopedics: A Review.

Heat transfer performance of a finned metal foam-phase change material (FMF-PCM) system incorporating triply periodic minimal surfaces (TPMS)

Properties and applications of additively manufactured metallic cellular materials: A review

State-of-the-art in heat exchanger additive manufacturing

This study presents an experimental evaluation of permeability of triply periodic minimal surfaces (TPMS). Permeability is widely used to characterize scaffolds for Tissue Engineering (TE) applications as it gives information about the structure porosity, pore size, tortuosity and pore interconnectivity which have an important impact in cell seeding and proliferation. Three different TPMS structures were used: Schwartz Diamond (SD), Gyroid (SG) and Schwartz Primitive (SP), in four different porosity levels (50, 60, 70 and 80%). Overall, the SG scaffold type was determined to be the most permeable one while the SD was the least permeable. Furthermore, the presence of microscopic inertial pressure losses was verified and the Forchheimer's law proved to be a good mathematical tool as a Darcy's law expansion for the calculation of the structure's permeability while the weak-inertia regime was hard to detect or quantify.

On the permeability of TPMS scaffolds.

Scaffolds for bone tissue engineering are porous structures that serve as support for cellular growth and, therefore, new tissue formation. The present work assessed the influence of the porous architecture of triply periodic minimal surface (TPMS) scaffolds on their macroscopic permeability behavior, combining numerical and experimental methods. The TPMS scaffolds considered were Schwartz D, Schwartz P, and Gyroid, which have been previously studied for bone tissue engineering, with 70% porosity. On the experimental side, these scaffolds were produced by MultiJet 3D printing and tested for fluid passage to calculate their permeability through Darcy’s Law. On the numerical side, finite element (FE) models of the scaffolds were simulated on ABAQUS® for fluid passage under compression to assess potential fluid concentration spots. The outcomes revealed that the design of the unit cell had a noticeable effect on both calculated permeability and FE computed fluid flow velocity, regardless of the identical porosity, with the Gyroid scaffold having higher permeability and the Schwartz P a lower probability of fluid trapping. Schwartz D had the worst outcomes in both testing modalities, so these scaffolds would most likely be the last choice for promoting cell differentiation onto bone cells. Gyroid and Schwartz P would be up for selection depending on the application and targeted bone tissue.

https://www.mdpi.com/1996-1944/12/8/1313/pdf

Tiago A.C. Pires

Papers

On the permeability of TPMS scaffolds.

Permeability versus Design in TPMS Scaffolds.

Fire resistance of concrete filled circular hollow columns with restrained thermal elongation

Numerical-experimental analysis of the permeability-porosity relationship in triply periodic minimal surfaces scaffolds

Micromechanical Behavior of TPMS Scaffolds for Bone Tissue Engineering