Functionally graded porous scaffolds in multiple patterns: New design method, physical and mechanical properties

Liu, Fei; Mao, Zhiping; Zhang, Peng; Zhang, Zhengwen; Jiang, Jinbao; Ma, Zhibo

doi:10.1016/j.matdes.2018.09.053

Cited by 268 publications

(109 citation statements)

References 43 publications

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“…The literature [23,134,136,181,182] on AM manufactured metal lattices raises the repeatability of highly porous scaffolds as a major concern that affects both reproducibility and predictability of their mechanical performance. Although FEM could predict the stiffness and strength of porous scaffolds, the accuracy of the prediction reported in most cases is low [183][184][185].…”

Section: Discussionmentioning

confidence: 99%

Mechanical performance of highly permeable laser melted Ti6Al4V bone scaffolds

Arjunan

Demetriou

Baroutaji

et al. 2020

Journal of the Mechanical Behavior of Biomedical Materials

125

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Critically engineered stiffness and strength of a scaffold are crucial for managing maladapted stress concentration and reducing stress shielding. At the same time, suitable porosity and permeability are key to facilitate biological activities associated with bone growth and nutrient delivery. A systematic balance of all these parameters are required for the development of an effective bone scaffold. Traditionally, the approach has been to study each of these parameters in isolation without considering their interdependence to achieve specific properties at a certain porosity. The purpose of this study is to undertake a holistic investigation considering the stiffness, strength, permeability, and stress concentration of six scaffold architectures featuring a 68.46-90.98% porosity. With an initial target of a tibial host segment, the permeability was characterised using Computational Fluid Dynamics (CFD) in conjunction with Darcy's law. Following this, Ashby's criterion, experimental tests, and Finite Element Method (FEM) were employed to study the mechanical behaviour and their interdependencies under uniaxial compression. The FE model was validated and further extended to study the influence of stress concentration on both the stiffness and strength of the scaffolds. The results showed that the pore shape can influence permeability, stiffness, strength, and the stress concentration factor of Ti6Al4V bone scaffolds. Furthermore, the numerical results demonstrate the effect to which structural performance of highly porous scaffolds deviate, as a result of the Selective Laser Melting (SLM) process. In addition, the study demonstrates that stiffness and strength of bone scaffold at a targeted porosity is linked to the pore shape and the associated stress concentration allowing to exploit the design freedom associated with SLM.

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Section: Discussionmentioning

confidence: 99%

Mechanical performance of highly permeable laser melted Ti6Al4V bone scaffolds

Arjunan

Demetriou

Baroutaji

et al. 2020

Journal of the Mechanical Behavior of Biomedical Materials

125

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“…The Gyroid surface can be expressed as [ 38 ]:

where constants a , b and c govern the unit cell size in three directions [ 39 ], and they are commonly the same in the designing process to obtain isotropic properties; the constant t controls the ratio of two volumes separated by the Gyroid surface and is termed as level parameter in this study. The sheet-based Gyroid structure can be generated from two individual and non-intersected surfaces with different level parameters via a Boolean difference operation between two volumes ( G t 1 and G t 2 ) surrounded by the surfaces as illustrated in Figure 1 .…”

Section: Methodologiesmentioning

confidence: 99%

Design and Characterization of Sheet-Based Gyroid Porous Structures with Bioinspired Functional Gradients

et al. 2020

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A new type of sheet porous structures with functionally gradients based on triply periodic minimal surfaces (TPMS) is proposed for designing bone scaffolds. The graded structures were generated by constructing branched features with different number of sheets. The design of the structure was formulated mathematically and five types of porous structure with different structural features were used for investigation. The relative density (RD) and surface area to volume (SA/V) ratio of the samples were analyzed using a slice-based approach to confirm their relationships with design parameters. All samples were additively manufactured using selective laser melting (SLM), and their physical morphologies were observed and compared with the designed models. Compression tests were adopted to study the mechanical properties of the proposed structure from the obtained stress–strain curves. The results reveal that the proposed branched-sheet structures could enhance and diversify the physical and mechanical properties, indicating that it is a potential method to tune the biomechanical properties of porous scaffolds for bone tissue engineering (TE).

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“…Similarly, Vijayavenkataraman et al [131] applied gradient strategies (changing rod diameter, cell size, and unit cell type) to three TPMSs (P, G, and D surface) to achieve the design of the biomimetic implants, which are satisfied with multiple requirements like porosity, modulus and pore size etc. In addition, other researchers have established gradient minimal surface structures for implants [124,[132][133][134]. However, the gradient direction of all the above implants is consistent with the loading direction, which is the longitudinal direction.…”

Section: Gradient Structure Designmentioning

confidence: 85%

“…The rod diameters of each layer vary, thereby changing the overall density of the lattice structure. (2) Unit cell changes in size [124]. The implant is composed of a plurality of unit cells.…”

Section: Gradient Structure Designmentioning

confidence: 99%

See 1 more Smart Citation

Additive Manufacturing of Customized Metallic Orthopedic Implants: Materials, Structures, and Surface Modifications

Bai

Cheng

Chen

et al. 2019

Metals

131

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Metals have been used for orthopedic implants for a long time due to their excellent mechanical properties. With the rapid development of additive manufacturing (AM) technology, studying customized implants with complex microstructures for patients has become a trend of various bone defect repair. A superior customized implant should have good biocompatibility and mechanical properties matching the defect bone. To meet the performance requirements of implants, this paper introduces the biomedical metallic materials currently applied to orthopedic implants from the design to manufacture, elaborates the structure design and surface modification of the orthopedic implant. By selecting the appropriate implant material and processing method, optimizing the implant structure and modifying the surface can ensure the performance requirements of the implant. Finally, this paper discusses the future development trend of the orthopedic implant.

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Functionally graded porous scaffolds in multiple patterns: New design method, physical and mechanical properties

Cited by 268 publications

References 43 publications

Mechanical performance of highly permeable laser melted Ti6Al4V bone scaffolds

Mechanical performance of highly permeable laser melted Ti6Al4V bone scaffolds

Design and Characterization of Sheet-Based Gyroid Porous Structures with Bioinspired Functional Gradients

Additive Manufacturing of Customized Metallic Orthopedic Implants: Materials, Structures, and Surface Modifications

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