Mechanical properties of energy-absorbing structures with triply periodic minimal surface topology

Functional graded materials are gaining increasing attention in tissue engineering (TE) due to their superior mechanical properties and high biocompatibility. Triply periodic minimal surface (TPMS) has the capability to produce smooth surfaces and interconnectivity, which are very essential for bone scaffolds. To further enhance the versatility of TPMS, a parametric design method for functionally graded scaffold (FGS) with programmable pore size distribution is proposed in this study. Combining the relative density and unit cell size, the effect of design parameters on the pore size was also considered to effectively govern the distribution of pores in generating FGS. We made use of Gyroid to generate different types of FGS, which were then fabricated using selective laser melting (SLM), followed by investigation and comparison of their structural characteristics and mechanical properties. Their morphological features could be effectively controlled, indicating that TPMS was an effective way to achieve functional gradients which had bone-mimicking architectures. In terms of mechanical performance, the proposed FGS could achieve similar mechanical response under compression tests compared to the reference FGS with the same range of density gradient. The proposed method with control over pore size allows for effectively generating porous scaffolds with tailored properties which are potentially adopted in various fields.

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The effect of porosity on the mechanical properties of 3D-printed triply periodic minimal surface (TPMS) bioscaffold

Bio-Design and Manufacturing ◽

10.1007/s42242-019-00054-7 ◽

2019 ◽

Vol 2 (4) ◽

pp. 242-255 ◽

Cited By ~ 3

Author(s):

Zizhen Cai ◽

Zehua Liu ◽

Xiaodong Hu ◽

Hekun Kuang ◽

Jinsong Zhai

Keyword(s):

Mechanical Properties ◽

Minimal Surface ◽

Periodic Minimal Surface ◽

Triply Periodic ◽

Triply Periodic Minimal Surface ◽

3D Printed

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Mechanical properties of 3D printed polymeric cellular materials with triply periodic minimal surface architectures

Materials & Design ◽

10.1016/j.matdes.2017.03.018 ◽

2017 ◽

Vol 122 ◽

pp. 255-267 ◽

Cited By ~ 94

Author(s):

Diab W. Abueidda ◽

Mete Bakir ◽

Rashid K. Abu Al-Rub ◽

Jörgen S. Bergström ◽

Nahil A. Sobh ◽

...

Keyword(s):

Mechanical Properties ◽

Minimal Surface ◽

Cellular Materials ◽

Periodic Minimal Surface ◽

Triply Periodic ◽

Triply Periodic Minimal Surface ◽

3D Printed

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Different Approaches for Manufacturing Ti-6Al-4V Alloy with Triply Periodic Minimal Surface Sheet-Based Structures by Electron Beam Melting

Materials ◽

10.3390/ma14174912 ◽

2021 ◽

Vol 14 (17) ◽

pp. 4912 ◽

Cited By ~ 1

Author(s):

Dmitriy Khrapov ◽

Maria Kozadayeva ◽

Kayrat Manabaev ◽

Alexey Panin ◽

William Sjöström ◽

...

Keyword(s):

Mechanical Properties ◽

Electron Beam ◽

Minimal Surface ◽

Wall Thickness ◽

Electron Beam Melting ◽

Mechanical Load ◽

Spot Size ◽

Periodic Minimal Surface ◽

Triply Periodic ◽

Triply Periodic Minimal Surface

Targeting biomedical applications, Triply Periodic Minimal Surface (TPMS) gyroid sheet-based structures were successfully manufactured for the first time by Electron Beam Melting in two different production Themes, i.e., inputting a zero (Wafer Theme) and a 200 µm (Melt Theme) wall thickness. Initial assumption was that in both cases, EBM manufacturing should yield the structures with similar mechanical properties as in a Wafer-mode, as wall thickness is determined by the minimal beam spot size of ca 200 µm. Their surface morphology, geometry, and mechanical properties were investigated by means of electron microscopy (SEM), X-ray Computed Tomography (XCT), and uniaxial tests (both compression and tension). Application of different manufacturing Themes resulted in specimens with different wall thicknesses while quasi-elastic gradients for different Themes was found to be of 1.5 GPa, similar to the elastic modulus of human cortical bone tissue. The specific energy absorption at 50% strain was also similar for the two types of structures. Finite element simulations were also conducted to qualitatively analyze the deformation process and the stress distribution under mechanical load. Simulations demonstrated that in the elastic regime wall, regions oriented parallel to the load are primarily affected by deformation. We could conclude that gyroids manufactured in Wafer and Melt Themes are equally effective in mimicking mechanical properties of the bones.

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Mechanical and FEA-Assisted Characterization of Fused Filament Fabricated Triply Periodic Minimal Surface Structures

Journal of Composites Science ◽

10.3390/jcs5020058 ◽

2021 ◽

Vol 5 (2) ◽

pp. 58

Author(s):

Nikolaos Kladovasilakis ◽

Konstantinos Tsongas ◽

Dimitrios Tzetzis

Keyword(s):

Mechanical Properties ◽

Size Effect ◽

Mechanical Behavior ◽

Minimal Surface ◽

Bottom Plate ◽

Static Compression ◽

Periodic Minimal Surface ◽

Triply Periodic ◽

Triply Periodic Minimal Surface ◽

The Impact

This paper investigates the mechanical behavior of additive manufactured Triply Periodic Minimal Surface (TPMS) structures, such as Gyroid, Schwarz Diamond and Schwarz Primitive. Fused Filament Fabrication (FFF) technique was utilized in order to fabricate lattice structures with different relative densities, at 10%, 20% and 30%, using Polylactic acid (PLA). The test specimens were formed by structural TPMS unit cells and they were tested under quasi-static compression. A finite element analysis (FEA) was performed in order to predict their stress-strain behavior and compare with the experimental results. The results revealed that each architecture influences the mechanical properties of the structure differently depending on the impact of size effect. The structures were designed as sandwich structures (with a top and bottom plate) to avoid significant deterioration of the mechanical behavior, due to the size effect and this was achieved at high relative densities. The Schwarz Diamond structure demonstrated the highest mechanical strength compared with the other architectures, while the Gyroid structure also revealed a similar mechanical performance. In addition, Schwarz Primitive structure showed increased energy absorption especially during plastic deformation. The overall results revealed that the integrity of the mechanical properties of the studied TPMS FFF printed structures deteriorates, as the relative density of the structures decreases.

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