Basal Plane Research Articles

Design for Additive Manufacturing of Lattice Structures for Functional Integration of Thermal Management and Shock Absorption

Design optimization through the integration of multiple functions into a single part is a highly effective strategy to reduce costs, simplify assembly, improve performance, and reduce weight. Additive manufacturing facilitates the production of complex structures by allowing parts consolidation, resulting in optimized designs, where multiple functions are integrated into a single component. This study presents a design for additive manufacturing method for integrating multiple lattice structures to achieve thermal management and shock absorption functions. The method follows modeling and simulation phases for dimensioning and optimizing solutions to deliver the design functions at different macro- and mesoscale levels. Hierarchical complexity was leveraged to design the two-levels structure in a single part, each delivering a specific function. Specifically, the external layer addresses energy absorption and thermal insulation, while the internal layer acts as a thermal battery by incorporating a phase change material. The design of a container carried by an unmanned aerial vehicle for the transport of healthcare and biological materials is presented. The container is shock-resistant and can maintain the content at 4 ± 2 °C for at least 1 h. As it operates passively without the need for additional energy-consuming devices, it is easy to operate and contributes to increased flight autonomy. A flight mission experiment for urgent transport of blood bags confirmed the capability of the container to preserve blood integrity. This case study demonstrates that the two-layer lattice structure design represents a highly efficient approach to multifunctional design optimization.

Comprehensive analysis of the compressive behavior of Fischer-Koch-S, F-RD, and neovius TPMS cellular structures in 3D-printed PLA specimens

This paper investigates the compression-tested mechanical properties of 3D Polylactic acid (PLA) printed Triply Periodic Minimal Surfaces (TPMS) lattice structures, exploring the impact of varying input parameters. The input parameters included in this study are cellular structure, printing speed, and unit cell size. This study serves as a valuable guide for achieving specific mechanical properties through the selection of optimal parameters. The three input parameters would have a major effect in the overall mechanical properties of the specimens. Four output parameters were studied in this experiment elastic modulus, yield stress, plateau stress, and toughness. A Desirability Function Analysis (DFA) was implanted to achieve the most optimal parameter combination and it was compared to the original parameters. By comparing the mechanical properties of the original nine samples against the predicted optimized parameter, the toughness was increased by 2.15%, elastic modulus increased by 108.33%, yield stress increased by 4% and plateau stress increased by 3.97%.

Designing Chiral Organometallic Nanosheets with Room-Temperature Multiferroicity and Topological Nodes.

Two-dimensional (2D) room-temperature chiral multiferroic and magnetic topological materials are essential for constructing functional spintronic devices, yet their number is extremely limited. Here, by using the chiral and polar HPP (HPP = 4-(3-hydroxypyridin-4-yl)pyridin-3-ol) as an organic linker and transition metals (TM = Cr, Mo, W) as nodes, we predict a class of 2D TM(HPP)2 organometallic nanosheets that incorporate homochirality, room-temperature magnetism, ferroelectricity, and topological nodes. The homochirality is introduced by chiral HPP linkers, and the change in structural chirality induces a topological phase transition of Weyl phonons. The room-temperature magnetism arises from the strong d-p spin coupling between TM cations and HPP doublet anions. The ferroelectricity is attributed to the breaking of spatial inversion symmetry in the lattice structure. Additionally, by adjusting the type of TMs, these nanosheets show rich and tunable band structures. Notably, all predicted materials are topologically nontrivial, featuring a quadratic nodal point around the Fermi level.

A preliminary study of linear accelerator-based spatially fractionated radiotherapy

PurposeThis study aimed to provide quantitative information for implementing Lattice radiotherapy (LRT) using a medical linear accelerator equipped with the Millennium 120 multi-leaf collimator (MLC). The research systematically evaluated the impact of varying vertex diameters and separations on dose distribution, peak-to-valley dose ratio (PVDR), and normal tissue dose.MethodsA cylindrical Virtual Water™ phantom was used to create LRT treatments using the Eclipse version 16.0 treatment planning system (Varian, Palo Alto, USA). The plans were optimized employing a 3 × 3 × 3 lattice structure with vertex diameters ranging from 0.5 to 2.0 cm and separations from 1.0 to 5.0 cm. The prescribed dose was 20.0 Gy to 50% of the vertex volume in a single fraction. Peak-to-valley dose ratio (PVDR) was calculated along three orthogonal axes, and normal tissue dose and monitor units (MU) were analyzed. Additionally, the modulation complexity score (MCS) was calculated for each plan to quantitatively assess treatment plan complexity.ResultsThe PVDR analysis demonstrated heterogeneous dose distribution, with optimal values below 30% in all directions for 5.0 cm separation. PVDR in the superior-inferior direction was consistently lower than in other directions. Normal tissue dose analysis revealed increasing mean dose with larger diameters and separations, while the volume receiving high doses decreased. MU analysis showed significant contributions from collimator angles of 315.0° and 45.0°. MCS values ranged from 0.02 to 0.17 for 0.5 cm vertex diameter and 0.08 to 0.20 for larger diameters (1.0-2.0 cm) across different separations, respectively.ConclusionsThis study demonstrates the technical feasibility of implementing LRT using a medical linear accelerator with Millennium 120 MLC. The findings provide insights into optimizing LRT treatment plans, offering a comprehensive quantitative reference for achieving desired dose heterogeneity while maintaining normal tissue protection.

Static and Dynamic Mechanical Behavior of Lattice Structures of Shape Memory Alloys

Static and Dynamic Mechanical Behavior of Lattice Structures of Shape Memory Alloys

A roadmap from the bond strength to the grain-boundary energies and macro strength of metals

Correlating the bond strength with the macro strength of metals is crucial for understanding mechanical properties and designing multi-principal-element alloys (MPEAs). Motivated by the role of grain boundaries in the strength of metals, we introduce a predictive model to determine the grain-boundary energies and strength of metals from the cohesive energy and atomic radius. This scheme originates from the d-band characteristics and broken-bond spirit of tight-binding models, and demonstrates that the repulsive/attractive effects play different roles in the variation of bond strength for different metals. Importantly, our framework not only applies to both pure metals and MPEAs, but also unravels the distinction of the bond strength caused by elemental compositions, lattice structures, high-entropy, and amorphous effects. These findings build a physical picture across bond strength, grain-boundary energies and strength of metals by using easily accessible material properties and provide a robust method for the design of high-strength alloys.

Application of Homogenization Method in Free Vibration of Multi-Material Auxetic Metamaterials

Different additive manufacturing modalities enable the production of multi-material components which can be used in a wide range of industrial applications. The prediction of the mechanical properties of these components via finite element modelling rather than through testing is critical in terms of cost and time. However, due to the higher computational time spent on the modelling of lattice structures, different methods have been investigated to accurately predict mechanical properties. For this purpose, this study proposes the use of a homogenization method in the two most common types of multi-material lattices: honeycomb and re-entrant auxetics. Modal analyses were performed, and the first six mode shapes were extracted from explicit and implicit models. The results were compared in terms of mode shapes and natural frequencies. The results showed that homogenization can be successfully applied to multi-material honeycomb and re-entrant auxetic lattices without compromising the accuracy. It was shown that the implicit models predict the natural frequencies with an error range of less than 6.5% when compared with the explicit models in all of the mode shapes for both honeycomb and re-entrant auxetic lattices. The Modal Assurance Criteria, which is an indication of the degree of similarity between the mode shapes of explicit and implicit models, was found to be higher than 0.996, indicating very high similarity.

Compression performance of 3D-printed ant-inspired lattice structures: An innovative design approach

In this study, three different ant-inspired lattice design types: single, double, and inverted double structures were considered due to ants’ excellent load-carrying weight ratio. Lattice structures were fabricated using the 3D printing method and polylactic acid filament was used as a printing material. The true blueprint images of the ant were used to obtain the parametric dimensions of the ant-inspired lattice structure. Hence, the presented innovative method for designing lattice structures can be a promising option for industrial sectors requiring high-strength structures. The quasi-static axial compression tests were conducted to evaluate the compression performance of the novel lattice structures. The compression performance of ant-inspired single lattice structures was compared based on specific force, specific energy absorption, and specific stiffness at different height values. The deformation stages and damage regions of ant-inspired lattice structures were analyzed to identify their critical regions during compression tests. The results indicated that as the height value increased, there was a notable decrease in specific force, specific energy absorption, and specific stiffness, along with buckling damage in the ant-inspired single lattice structures. Among the three design types, the ant-inspired inverted double lattice structure showed better compression performance compared to the ant-inspired double lattice structure; however, the ant-inspired single lattice structure with a height of 30 mm exhibited the highest overall compression performance.

Atomic Gap-State Engineering of MoS2 for Alkaline Water and Seawater Splitting.

Transition-metal dichalcogenides (TMDs), such as molybdenum disulfide (MoS2), have emerged as a generation of nonprecious catalysts for the hydrogen evolution reaction (HER), largely due to their theoretical hydrogen adsorption energy close to that of platinum. However, efforts to activate the basal planes of TMDs have primarily centered around strategies such as introducing numerous atomic vacancies, creating vacancy-heteroatom complexes, or applying significant strain, especially for acidic media. These approaches, while potentially effective, present substantial challenges in practical large-scale deployment. Here, we report a gap-state engineering strategy for the controlled activation of S atom in MoS2 basal planes through metal single-atom doping, effectively tackling both efficiency and stability challenges in alkaline water and seawater splitting. A versatile synthetic methodology allows for the fabrication of a series of single-metal atom-doped MoS2 materials (M1/MoS2), featuring widely tunable densities with each dopant replacing a Mo site. Among these (Mn1, Fe1, Co1, and Ni1), Co1/MoS2 demonstrates outstanding HER performance in both alkaline and seawater alkaline media, with overpotentials at a mere 159 and 164 mV at 100 mA cm-2, and Tafel slopes at 41 and 45 mV dec-1, respectively, which surpasses all reported TMD-based nonprecious materials and benchmark Pt/C catalysts in HER efficiency and stability during seawater splitting, which can be attributed to an optimal gap-state modulation associated with sulfur atoms. Experimental data correlating doping density and dopant identity with HER performance, in conjunction with theoretical calculations, also reveal a descriptor linked to near-Fermi gap state modulation, corroborated by the observed increase in unoccupied S 3p states.

High-throughput design of a light and strong refractory eutectic medium entropy alloy with outstanding He-ion irradiation resistance.

Light, strong, and radiation-tolerant materials are essential for advanced nuclear systems and aerospace applications. However, the comprehensive properties of current radiation-tolerant materials are far from being satisfactory in harsh operating environments. In this study, a high-throughput-designed NbVTaSi refractory eutectic medium entropy alloy realizes the controllable formation of the β-Nb5Si3 phase with a high content and has outstanding comprehensive properties, i.e., lightweight, high yield strengths at room temperature and 850°C, and excellent He-ion irradiation resistance. According to density functional theory calculations and experimental findings, the prefabricated lattice distortion of the Nb50V42Ta8 phase leads to great phase stability under severe He-ion irradiation conditions, while the dual characteristics of the semi-coherent interface and hyperstatic lattice structure of the high-content β-Nb5Si3 phase dominate its outstanding He-ion irradiation resistance. This study sheds light on the design strategy for comprehensive properties and development of future radiation-tolerant materials for advanced nuclear systems and aerospace applications.

Effect of Elementary Unit Configurations on the Mechanical Performance of Periodic Lattice Structures to Architect Porous Scaffolds by FEM-Driven Additive Manufacturing

Effect of Elementary Unit Configurations on the Mechanical Performance of Periodic Lattice Structures to Architect Porous Scaffolds by FEM-Driven Additive Manufacturing

Enhancing mechanical and energy absorption properties of additively manufactured polyamide lattice structures through hybrid-structuring and strut reinforcement: a numerical and experimental study

Enhancing mechanical and energy absorption properties of additively manufactured polyamide lattice structures through hybrid-structuring and strut reinforcement: a numerical and experimental study

Experimental and Numerical Analysis of Titanium 3D Body-Centered Cubic Lattice Structure Additively Manufactured Using Selective Laser Melting

Experimental and Numerical Analysis of Titanium 3D Body-Centered Cubic Lattice Structure Additively Manufactured Using Selective Laser Melting

Single-Atom Suture.

In atomically thin two-dimensional (2D) materials, grain boundaries (GBs) are ubiquitous, displaying a profound effect on the electronic structure of the host lattice. The random configuration of atoms within GBs introduces an arbitrary and unpredictable local electronic environment, which may hazard electron transport. Herein, by utilizing the Pt single-atom chains with an ultimate one-dimensional (1D) feature (width of a single atom and length up to tens of nanometers), we realized the suture of the electron pathway at GBs of diversified transition metal dichalcogenides (TMDCs). Theoretical calculations reveal that the construction of Pt single-atom sutures (SAS) prompts the emergence of electronic states proximal to the Fermi level, effectively modulating the transformation of the electronic structure from semiconductivity to metallicity. This transformation underscores the pivotal role of Pt SAS in reconfiguring the electron pathway. Benefiting from this, the Pt SAS-MoS2 emerges as an excellent catalyst, exhibiting an overpotential of 41 mV at 10 mA cm-2 and a Tafel slope of 54 mV dec-1 in hydrogen evolution reaction. Our results offer an understanding of the electron conduction pathway contributed by ultraordered atomic arrangement and the innovative mechanisms for future potential catalysts with an optimized architecture.

Graphene Oxide as a Self-Carbocatalyst to Facilitate the Ring-Opening Polymerization of Glycidol for Efficient Polyglycerol Grafting.

Grafting carbon-based nanomaterials (CNMs) with polyglycerol (PG) improves their application potentials in biomedicine and electronics. Although "grafting from" method offers advantages over "grafting to" one in terms of operability and versatility, little is known about the reaction process of glycidol with the surface groups onto CNMs. By using graphene oxide (GO) as a multi-functional model material, we examined the reactivity of the surface groups on GO toward glycidol molecules via a set of model reactions. We reveal that carboxyl groups spontaneously react with the epoxide ring with no need of catalyst, while GO catalyzes the reactions of hydroxyl groups with the epoxide of glycidol. In addition, the hydroxyl group of glycidol can open the epoxide in the basal plane of GO. The subsequent polymerization of PG is supposed to propagate at the primary and/or the secondary hydroxyl groups, generating a ramified PG macromolecule with random branch-on-branch topology. In addition, ketones, benzyl esters and aromatic ethers are found not to react with glycidol even in the presence of GO, while the aldehydes are easily oxidized into carboxyl groups under ambient condition, behaving then as the carboxyl groups. Our findings pose the foundation for understanding the polymerization mechanism of PG on CNMs.

Constructing the Dirac Electronic Behavior Database of Under‐Stress Transition Metal Dichalcogenides for Broad Applications

AbstractDiscovering and utilizing the unique optoelectronic properties of transition metal dichalcogenides (TMDCs) is of great significance for developing next‐generation electronic devices. In particular, research on Dirac state modulations of TMDCs under external strains is lacking. To fill this research gap, it has established a comprehensive database of 90 types of TMDCs and their response behaviors under external strains have been systematically investigated regarding the presence of Dirac cones and electronic structure evolutions. Among all the conditions, 27.3% of the TMDCs are Dirac materials with three distinct types of Dirac cones, which are mainly attributed to the electron localizations induced by external strains. TMDCs based on tellurides with 1H phase favor the formation of Dirac cones under stresses, leading to metallic‐like properties and ultra‐fast charge transportation. Correlations among Dirac cones, energy, electronic properties, and lattice structures have been revealed, offering critical references for modulating the properties of well‐known TMDCs. More importantly, it has confirmed that the phase transition points are not sufficient for the appearance of Dirac cones. This work provides critical guidance to facilitate the development of TMDCs‐based superconducting and optoelectronic devices for broad applications.

Temperature Uniformity Control of 12-Inch Semiconductor Wafer Chuck Using Double-Wall TPMS in Additive Manufacturing.

In semiconductor inspection equipment, a chuck used to hold a wafer is equipped with a cooling or heating system for temperature uniformity across the surface of the wafer. Surface temperature uniformity is important for increasing semiconductor inspection speed. Triply periodic minimal surfaces (TPMSs) are proposed to enhance temperature uniformity. TPMSs are a topic of increasing research in the field of additive manufacturing and are a type of metamaterial inspired by nature. TPMSs are periodic surfaces with no intersections. Their continuous curve offers self-support during the additive manufacturing process. This structure enables the division of a single space into two domains. As a result, the heat transfer area per unit volume is larger than that of general lattice structures, leading to a superior heat transfer performance. This paper proposes a new structure called a double-wall TPMS. The process of creating a double-walled TPMS by adjusting the thickness of the sheet TPMS was investigated, and its thermal performance was studied. Finally, a double-wall TPMS was applied to the chuck. The optimal designs for the diamond and gyroid structures exhibited a difference in surface temperature uniformity of 0.23 °C and 0.66 °C, respectively. Accordingly, the models optimized with the double-wall TPMS are proposed.

Optimising β-Ti21S Alloy Lattice Structures for Enhanced Femoral Implants: A Study on Mechanical and Biological Performance.

The metastable β-Ti21S alloy exhibits a lower elastic modulus than Ti-6Al-4V ELI while maintaining high mechanical strength and ductility. To address stress shielding, this study explores the integration of lattice structures within prosthetics, which is made possible through additive manufacturing. Continuous adhesion between the implant and bone is essential; therefore, auxetic bow-tie structures with a negative Poisson's ratio are proposed for regions under tensile stress, while Triply Periodic Minimal Surface (TPMS) structures with a positive Poisson's ratio are recommended for areas under compressive stress. This research examines the manufacturability and quasi-static mechanical behaviour of two auxetic bow-tie (AUX 2.5 and AUX 3.5) and two TPMS structures (TPMS 2.5 and TPMS 1.5) in β-Ti21S alloy produced via laser powder bed fusion. Micro-CT reveals printability issues in TPMS 1.5, affecting pore size and reducing fatigue resistance compared to TPMS 2.5. AUX 3.5's low stiffness matches cancellous bone but shows insufficient yield strength and fatigue resistance for femoral implants. Biological tests confirm non-toxicity and enhanced cell activity in β-Ti21S structures. The study concludes that the β-Ti21S alloy, especially with TPMS 2.5 structures, demonstrates promising mechanical and biological properties for femoral implants. However, challenges like poor printability in TPMS 1.5 are acknowledged and should be addressed in future research.

Biofunctionalisation of porous additively manufactured magnesium-based alloys for Orthopaedic applications: A review.

Magnesium (Mg) alloys have gained significant attention as a desirable choice of biodegradable implant for use in bone repair applications, largely owing to their unique material properties. More recently, Mg and Mg-based alloys have been used as load-bearing metallic scaffolds for bone tissue engineering applications, offering promising opportunities in the field. The mechanical properties and relative density of Mg-based alloys closely approximate those of natural human bone tissue, thereby mitigating the risk of stress-shielding effects. Furthermore, the inherent biodegradability of Mg-based alloys eliminates the necessity for a second surgical procedure for the removal of the implant, a frequent requirement with conventional non-degradable implants. However, a notable challenge remains in managing the high corrosion rate of Mg and Mg-based alloys within physiological environments to ensure that they meet the necessary functional requirements. Consequently, a comprehensive analysis and understanding of the corrosion behaviour of Mg and Mg-based alloys, coupled with optimisation of their surface properties, assume pivotal significance to ensure successful clinical application. The personalized 3D printing of Mg and Mg-based alloy implants represents a paradigm shift, offering a plethora of advantages, foremost among them being the enhancement of the bone healing process facilitated by the degradable porous structure conducive to bone ingrowth. Also, the emergence of surface functionalisation techniques for Mg-based implants amalgamates the mechanical and degradation properties inherent to metals with the enhanced biofunctionality offered by these coatings. This synergy presents a highly promising avenue for using Mg-based implants as temporary orthopaedic and dental solutions. This comprehensive review provides a detailed analysis of recent advancements encompassing alloying elements, additive manufacturing processes, lattice structures and biofunctionalised coatings to tailor the corrosion resistance, mechanical properties and biocompatibility of Mg-based orthopaedic implants.

PARAMETRIC DESIGN AND ADAPTIVE SIZING OF LATTICE STRUCTURES FOR 3D ADDITIVE MANUFACTURING

The present research is developed into the realm of industrial design engineering and additive manufacturing by introducing a parametric design model and adaptive mechanical analysis for a new lattice structure, with a focus on 3D additive manufacturing of complex parts. Focusing on the land-scape of complex parts additive manufacturing, this research proposes geometric parameterization, mechanical adaptive sizing, and numerical validation of a novel lattice structure to optimize the final printed part volume and mass, as well as its structural rigidity. The topology of the lattice structures exhibited pyramidal geometry. Complete parameterization of the lattice structure ensures that the known geometric parameters adjust to defined restrictions, enabling dynamic adaptability based on its load states and boundary conditions, thereby enhancing its mechanical performance. The core methodology integrates analytical automation with mechanical analysis by employing a model based in two-dimensional beam elements. The dimensioning of the lattice structure is analyzed using rigidity models of its sub-elements, providing an evaluation of its global structural behavior after applying the superposition principle. Numerical validation was performed to validate the proposed analytical model. This step ensures that the analytical model defined for dimensioning the lattice structure adjusts to its real mechanical behavior and allows its validation. The present manuscript aims to advance additive manufacturing methodologies by offering a systematic and adaptive approach to lattice structure design. Parametric and adaptive techniques foster new industrial design engineering methods, enabling the dynamic tailoring of lattice structures to meet their mechanical demands and enhance their overall efficiency and performance. Keywords: Computer-Aided Design, Industrial Design, Innovative Design, Additive Manufacturing, FEM Simulations