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This study investigates the microstructure and compressive behaviour of PLA/PHA-wood lattice structures manufactured using fused filament fabrication (FFF). The primary objective is to evaluate the effects of defects, such as porosity and surface roughness, on the mechanical properties of these lattice structures. X-ray micro-tomography (XRT) and finite element analysis are employed to compare CAD models with real lattice structures, offering insights into defect-induced performance deviations. The novel approach integrates experimental and numerical methods to better understand damage accumulation in porous structures. The methodology includes uniaxial compression testing and image processing for microstructural characterization. Results reveal significant differences in relative density and stress concentration due to manufacturing defects. In particular, 3D printed lattice structures display typical cellular material behaviour with a primary bending deformation mechanism. X-ray tomography reveals that process-induced porosity generate stress heterogeneity, which is not captured from CAD-based model resulting in an overestimation of the stiffness. The study concludes that accounting for these defects can be quantified by shifting the target relative density to compensate lack of performance in 3D-printed lattice materials.

3D lattice structures comprise a connected network of segments that allow positioning of the base material where needed while maintaining an open-cell characteristic. These structures represent an ideal lightweight core material for high-performance sandwich panels. This work presents, for the first time, the performance of lattice-based cores fabricated via indirect additive manufacturing using pultruded Carbon Fiber Reinforced Polymer (CFRP) rods. The CFRP sandwich panels were tested under out-of-plane compression, and their compressive properties and failure modes were predicted via analytical and FE analyses, later contrasted with mechanical testing. Finally, the study compares favorably with similar core materials found in the literature.

Bone microstructures or scaffolds mimicking natural bone characteristics find widespread applications in bone tissue engineering (BTE). To accurately replicate a personalized bone structure, we developed a heterogeneous scaffold by combining medical image data with the octree adaptive subdivision technique. The transformations between Hounsfield units (HU)-strength and strength-lattice features were implemented for mapping bone information to the scaffold. Initially, HU values from computed tomography (CT) images were smoothly converted into corresponding strengths through a rational Bezier curve. Then, these strengths were further translated into the features of lattice structures, specifically the strut diameter and subdivision level. The novel concept of adaptive octree subdivision, executed on the lattices, allows for controlling bone porosity and mechanical property even at local levels. As a result, a personalized heterogeneous scaffold accurately simulating natural bone structure was designed and manufactured for bone grafting application on a 3D-printed alveolar model. The scaffold has an outer cortical bone layer capable of withstanding pressures of up to 208.2 MPa, while the inner cancellous bone exhibits a high porosity ranging from 77.6 % to 93.6 %. The research provides an elegant yet effective approach to the generation of bone microstructures, opening up practical BTE applications.

Ti6Al4V lattice structures (LSs) have great potentials in medical implants due to their excellent biocompatibility and high strength-to-weight ratio. This paper investigates the manufacturability and performance of unique Ti6Al4V heterogeneous glass sponge (GS) LSs fabricated via laser powder bed fusion (LPBF). Compared with the commonly used LSs, including Cross, body-centered cubic (BCC), Diamond and octet-truss (OCT), Ti6Al4V GS LSs exhibit the strongest compressive strength and energy absorption ability of 58 MPa and 23.84 J/cm3, respectively. Finite element (FE) models are established to evaluate the macroscopic deformation, microscopic stress and strain evolution in the solid struts of five different LSs. Local plastic stresses are found to generate near the nodes of Cross, BCC, Diamond and OCT LSs, thus forming plastic hinges, while the GS LSs can evenly transfer local plastic stresses to the grid-like rods of each layer, eventually showing a uniform stress distribution. Moreover, all the LSs are featured with satisfactory biocompatibility concerning cytotoxicity, cell proliferation, and cell attachment. The results indicate that the Ti6Al4V GS LSs can address the conflict between lightness and strength simultaneously, thus achieving excellent energy absorption performance, compressive properties and great biocompatibility, endowing it with tremendous application potential in the field of medical implants.

Lattice structures have been a hot topic recently owing to their superior mechanical properties, which are significantly influenced by the unit cell structure. By leveraging the power of deep learning, inverse design can be conducted on the unit cell structure based on the mechanical properties of its lattice structure. Assisted by deep learning, this study introduces a novel data-driven approach to design three-dimensional (3D) unit cells for lattice structures with anticipated properties. The approach can be efficiently and accurately applied to various unit cell structures. An auto-encoder is trained to extract the geometric features from unit cell point clouds. The effective mechanical properties of the lattice structures are calculated by combining the homogenization method and the finite element method. Subsequently, a mapping relationship between mechanical properties and geometric features is established through the multi-layer perceptron neural network. The models are ultimately employed to design 3D unit cells given anticipated properties of lattice structures. The results show that the mechanical properties of the generated unit cells satisfy the anticipated values. The applications of proposed method are demonstrated in orthopedic implants, new hybrid unit cells, and functionally gradient structures. Furthermore, the method can be extended to unit cell design across diverse domains.

Additive Manufacturing (AM) technologies are at the forefront of technological development in machine design as they allow the production of complex parts with high stiffness-to-weight ratios, such as lattice structures, that conventional production processes cannot manufacture. Despite the advantages of AM and lattice structures, their potential is currently limited by concerns related to their fatigue strength due to process-related intrinsic defects. Considering that fatigue is a leading cause of mechanical failures that require costly maintenance, the interest in understanding the fatigue strength of AMed lattice structures is evident.This work explores the applicability of the Linear Elastic Fracture Mechanics (LEFM) for predicting the fatigue limit of lattice structures, building on the positive results obtained for AMed fully-dense materials. It includes a literature review of the experimental fatigue analysis of lattice structures, highlighting the experimental evidence of the fundamental role of AM defects and notches on the fatigue strength of AMed lattice structures. The main conclusions are that AMed lattice structures should be considered defective and notched materials, and the fatigue assessment should be performed with LEFM-based approaches. Lastly, this paper validates LEFM-based predictions against 400+ experimental data for AMed materials from the literature, including small-sized specimens and lattice structures.

In this study, an analytical and numerical analysis of a hybrid sandwich structure with a lattice core produced by additive manufacturing with composite facesheets is carried out. This paper aims to analytically calculate the mechanical behavior of the hybrid sandwich structure under three-point bending and to verify the results by the finite element method. The analytical method used in this article for the analysis of the composite sandwich structure is the First-Order Shear Deformation Theory (FSDT). The numerical analysis of the hybrid sandwich structure was performed in ANSYS. In the analyses, homogenized models of lattice structures, which had been previously validated, were employed to reduce the number of elements and thereby save time during the solution process. As a result of the study, an extensive investigation into the deformation, shear, and normal stress values of sandwich structures with lattice cores of varying aspect ratios has been carried out. The findings suggest a potential for optimization in lightweight structures, which could lead to innovative advancements in design and manufacturing processes within the aerospace and automotive sectors.

Lightweight lattice structures can have their mechanical properties and failure modes predicted through computer simulation. This approach has great potential for use in aerospace, the automotive industry, and defense equipment. However, due to the limitations of the LPBF process, fabricated lattice structures contain internal defects that affect the compression response, which leads to high-level errors in finite element method (FEM) predictions and experimental results. Thus, in this paper, a finite element model considering the effect of pore defects was built by using finite element simulation in connection with the Gurson-Tvergaard-Needleman (GTN) damage model to investigate the compressive behavior and mechanical response of the body-centered cubic lattice structure of AlSi10Mg alloys prepared by the LPBF process. A three-dimensional reconstruction of the molded BCC lattice structure was performed by computed tomography (CT) to obtain the structure's distribution and shape of micropores. Using a combination of simulation (FEM-GTN) and experimentation, the effects of process parameters on the compressive properties and mechanical behavior of the BCC lattice structure during quasi-static compression were investigated. The results show that the FEM simulation results corrected by the GTN damage model are in better accordance with the experimental results (the error rate is reduced by more than 10 %) compared to the FEM simulation results without considering the influence of the pore defects, which proves the higher accuracy of the FEM-GTN simulation model. This work provides a reference for the property prediction and fabrication of high-performance, lightweight lattice structures.

Lattice structures, one type of mechanical metamaterials, exhibit excellent mechanical properties such as a high strength-to-weight ratio and energy absorption capacity. However, predicting the stress–strain relationship of lattice structures remains a challenge because the mechanical behaviors of additively manufactured lattices are affected by both the structure parameters of a lattice and process conditions. This study proposes a machine learning (ML)-based predictive modeling framework to predict the entire stress–strain curves, compressive modulus, and energy absorption of lattice structures with varying structure and process parameters. Feature engineering techniques are used to transform raw data into new data representations compatible with ML models, including artificial neural networks, long short-term memory (LSTM), and convolutional neural networks (CNN). Two novel feature representations, including polygons and colormaps, are developed to transform structure and process parameters from tabular format into image format for CNN. The LSTM model that predicts stress–strain curves achieves a minimum mean absolute percentage error (MAPE) of 0.147. The CNN (colormap) model achieves a minimum MAPE of 0.174 when predicting compressive modulus. The ANN and LSTM models achieve a minimum MAPE of 0.068 when predicting energy absorption. The training time to build these ML models is less than 6 min.

Additively manufactured mechanical metamaterials are gaining prominence in lightweight energy-absorption applications due to their exceptional mass-specific properties. Herein, we examine the energy absorption characteristics of micro-architected truss-, shell- and plate-lattice structures, namely, Octet, Kelvin, Gyroid, SC, BCC and FCC over a range of relative densities under quasi-static compression via both experiments and finite element analysis (FEA). Employing different 3D printing methods, namely, Digital Light Processing, Selective Laser Sintering and Material Jetting, the lattices were fabricated using PlasGray™ (photo-resin based plastic), PA12 (Nylon) and VeroWhite (photo-resin based rigid plastic) respectively. Our results indicate that the SC lattice structure outperforms in terms of stiffness and strength, while the Gyroid lattice outperforms in terms of energy absorption efficiency (η). At lower relative densities (

This work involves the study of wind impact on a lattice structure. Permeable lattice structures are widely used in construction all over the world (oil derricks and power line pylons, etc.); at the same time, the aerodynamic forces acting on such structures may make a decisive contribution to their stability. There are several methods of lattice structure computation for wind impacts: a computation according to the existing normative documents and experimental and numerical simulation. Each of the above methods has its own merits, demerits, and difficulties. Thus, the normative documents do not allow to compute complex space-frame structures. In this work a computational and experimental approach is utilized. An experimental study is conducted in a wind tunnel to determine the integral aerodynamic characteristics, while the local aerodynamic characteristics are determined based on the results of numerical simulation in a CFD complex. A valid numerical model is used the parameters of which ensure the reconciliation of the obtained results with the experiment data. At the next stage a vortex resonance excitation of the lattice structure is studied. This methodology makes it possible both to determine the values of aerodynamic coefficients necessary for computing the wind load on the structure as a whole and evaluate the vortex resonance excitation probability.

The additive manufacturing (AM) of nitinol (NiTi) has gained considerable attention due to the capability of this material and processing combination to produce complex structures with desired shape memory or superelastic properties. Finite element analysis models were developed in this work to simulate the load-bearing capability of Laser Powder Bed Fusion (PBF-LB) produced NiTi lattice structures. The Auricchio numerical method, with exponential hardening law, was implemented within the FEA model to take account of the martensite-austenite reorientation upon change of stress state. The strut diameter and the unit cell side length were varied which in turn varied the lattice relative density. The lattice structures were subjected to 7 % compressive strain under isothermal conditions. The highest energy absorption efficiency of 40 % was achieved from the lattice structure with a strut diameter of 2 mm, a 6 mm unit cell side length, and a relative density of 42 %; however, the highest specific peak stress was recorded within the lattice structure having a strut diameter of 2.5 mm, a 4 mm unit cell side length, and a relative density of 62 %. Transient analysis was performed by varying the compression rate from 0.25 mm/s to 1 mm/s. For all loading conditions, the energy absorption increased linearly until a stable stress plateau was reached. Moreover, for these examined compression rates, the maximum stress absorption efficiencies varied within the range of 25 %–33 %.

Mass reduction of mechanical systems is a recurrent objective in engineering, which is often reached by removing material from its mechanical parts. However, this material removal leads to a decrease of mechanical performances for the parts, which must be minimized and controlled to avoid a potential system failure. To find a middle-ground between material removing and mechanical performances), material must be kept only in areas where it is necessary, for example using stress-driven material removal methods. These methods use the stress field to define the local material removal based on two local parameters: the local volume fraction vf and the structural anisotropy orientation β. These methods may be based on different types of cellular structure patterns: lattice-based or bio-inspired. The long-term objective of this study is to improve the performance of stress-driven methods by using the most efficient pattern. For this purpose, this study investigates the influence of vf and β on the mechanical stiffness of three planar cellular structures called Periodic Stress-Driven Material Removal (PSDMR) structures. The first, taken from the literature, is bio-inspired from bone and based on a square pattern. The second, developed in this study, is also bio-inspired from bone but based on a rectangular pattern. The third is a strut-based lattice pattern well documented in the literature for its isotropic behavior. These three patterns are compared in this study in terms of relative longitudinal stiffness, obtained through linear elastic compressive tests by finite element analysis. It is highlighted that each PSDMR pattern has a specific domain in which it performs better than the two others. In future works, these domains could be used in stress-driven material removal methods to select the most adequate pattern or a mix of them to improve the performances of parts.

Scaling laws represent an efficient way to describe complex physical phenomena efficiently and reliably by simplified relative quantities, which are holistic in the sense that they are invariant to changes in scale and therefore often universal. During part manufacturing in laser powder bed fusion additive manufacturing several such complex physical phenomena arise leading to unstable melt pool behavior and part porosity. Correlating processing parameters with melt pool quantities and eventually part properties such as porosity computationally efficiently can enable real-time build failure detection and process adaption leading to zero scrap rates in additive manufacturing. The efficient and reliable process-property correlation for dense materials is an ongoing field of research, whereas architected cellular and lattice structures, which are becoming more and more relevant in the context of additive manufacturing are rarely considered in this regard. In this contribution, a dimensionless number and the corresponding scaling law are derived to describe the correlation between porosity and process parameters for components manufactured by laser powder bed fusion. The scaling law is tested and validated for the commonly used alloys Ti-6Al-4V and AlSi10Mg on both dense and lattice structures regarding its suitability to predict the type and amount of porosity in additively manufactured components. The objective of this work is to foster reliable and predictable part quality and enable quality-driven build rate optimization.

Additive manufacturing (AM) allows for the creation of novel complex structures previously impossible using traditional subtractive methods; however, there is a need for new design approaches to fully exploit this potential. Metal lattice structures have attracted attention for their broad customisable range of configurations and potential properties, and to take advantage of these possibilities there is a need for intelligent design tools to optimise the lattice according to the desired application and properties. This study presents and demonstrates a method to automatically design lattice structures which achieve a desired compressive stress–strain curve and satisfy user-defined manufacturing limits. A genetic algorithm iterates selected design variables (unit cell aspect ratio, strut taper, and thickness gradient) and minimises the error between the target stress–strain curve and predicted curve which is determined via automated finite element (FE) modelling of each lattice design. The optimised design is validated through manufacture and compression testing of 17-4PH stainless steel lattice structures, and micro-CT imaging to assess build quality. The tool's versatility is demonstrated by successfully designing lattices to fit a range of target curves. This work demonstrates the potential of this smart inverse design tool to exploit AM and optimise lattice design based on desired performance. The custom written design tool presented in this study is available open source at https://github.com/I-Form/LiDOT.

This work discusses the combined effect of the microstructure and geometry on the deformation modes and energy-absorbing characteristics of laser powder bed fusion (LPBF)-manufactured Inconel 718 (IN718) hexagonal honeycomb structures tested under quasi-static compression. Three different geometries of the hexagonal cells, varying only in the cell wall thickness (0.4, 0.6 and 0.8 mm) were manufactured using LPBF. Electron backscatter diffraction (EBSD) imaging of the three studied geometries revealed three distinct zones of grain morphologies and textures across the 0.6 and 0.8 mm cell walls and only two zones and higher overall texture across the 0.4 mm cell walls. Miniature tensile tests were performed on 0.4 and 0.8 mm thick tensile samples to evaluate the thickness and orientation effects on the parent material behavior. Each hexagonal geometry was loaded in three different directions resulting in nine study sets. Exhibiting monotonically increasing plateau stress and specific energy absorbed (SEA) in addition to the high SEA/plateau stress ratios, LPBF-manufactured IN718 hexagonal honeycomb structures were demonstrated to be a viable candidate for additively-manufactured (AMed) metallic lattice structures in energy absorption applications. The reduction in the cell wall thickness influenced the instability failure mechanism for the in-plane load direction X1 but no pronounced effect was observed for the in-plane direction X2. As a result of the coupled change of the material properties with the variation in the cell wall thickness, a non-normalized anisotropic form of the Gibson-Ashby model for stochastic foams was proposed to characterize the honeycomb-structure mechanical properties. The findings of this paper more generally provide useful insights into optimizing the design of metallic AMed lattice structures.

Triply periodic minimal surface structures (TPMS) are continuously adopted in the architectural engineering and aircraft sectors in pursuit of noise mitigation. The airflow resistivity significantly influences the acoustic performance of lattice structures. The present work is a step toward designing appropriate structures of TPMS to obtain desired acoustics performance using the standard of ISO 9053–1:2018(E). In this work, the four TPMS lattices Gyroid, Diamond, Lidinoid, and Split P have been designed with three different parameters (porosity, sample length, and diameter) to predict the airflow resistivity and pressure drop of the structures. Various experiment sets were conducted on customized airflow resistivity experimental apparatus for cylindrical lattices with multiple parameters to identify the most effective lattice structures. Based on the findings, it was observed that lattice structures with less porosity, sample length, and sample diameter depict the highest level of airflow resistivity and pressure drop. However, for all four lattices, close differences in airflow resistivity values were noticed.

Numerical modelling is particularly advantageous for analysing structures with complex behaviour. It is used to predict the mechanical properties of structures. Analytical modelling, on the contrary, has limited capacity for predicting the behaviour, particularly of structures, because it is based on mathematical equations that do not always exactly represent the geometry of the model. In such cases, numerical modelling is used for predicting structural bending, axial deformation, and buckling behaviour. This study documents numerical modelling of different types of polygon structures. To reduce computation costs, planar and extruded Ti6Al4V(ELI) hexagonal shell structures were used to predict stresses in the out-of-plane and in-plane directions. This was followed by numerical modelling of different types of planar polygon structures to predict their load-bearing capacity and stiffness. Thereafter, the hexagonal polygon was subjected to out-of-plane and in-plane uniaxial compression loads. This was done to compare the bending and buckling behaviour of finite element (FE) models to analytical models. The numerical and analytical results were then compared to determine how the ratio (t/L) of the wall thickness (t) and length of the polygon members (L) influenced the effective stiffness of the hexagonal polygon. The triangular polygon was seen to have the greatest load-bearing capacity and stiffness of all polygons that were modelled. The hexagonal model was observed to generate deformations due to compression, similar to those reported in literature. The critical buckling loads for the analytical honeycomb (HC) models were found to be below the yield stress for (1-, 1.125-, and 1.25-mm wall thicknesses) and above the yield stress for all FE HC models, respectively. The effective stiffness of the HC models were observed to increase with the increasing (t/L) ratio, for both the numerical and analytical models.

Powder bed fusion (PBF) processes enable the manufacturing of complex components in a time- and cost-efficient manner. Especially lattice structures are currently focused since they show varying mechanical properties, including different deformation and damage behaviors, which can be used to locally tailor the mechanical behavior. However, the present process-structure-property relationships are highly complex and have to be understood in detail in order to enable an implementation of PBF manufactured lattice structures in safety-relevant applications. Within the present work Ti6Al4V lattice structures were manufactured by electron beam powder bed fusion of metals (PBF-EB/M). Based on the classification of bending- and stretch-dominated deformation behavior, two different lattice types, i.e. body-centered cubic like (BCC-) and face-centered cubic like (F2CCZ) structures were selected. Microstructural features were detected to evaluate if potential different microstructures can occur due to different lattice types and to answer the question if microstructural features might contribute to the mechanical behavior shown in this work. Furthermore, X-ray microfocus computed tomography (μCT) analysis were carried out to enable a comparison between the computer-aided designed (CAD) and as-built geometry. For mechanical characterization, quasi-static and cyclic tests were used. In particular, the BCC lattice type showed a more ductile material behavior whereby higher stiffness and strength was determined for the F2CCZ lattice type. Additionally, different in-situ measurement techniques such as direct current potential drop system and digital image correlation could be deployed to describe the damage progress both under quasi-static and cyclic loading.

Lattices based on triply periodic minimal surfaces (TPMS) are attracting increasing interest in seminal industries such as bone tissue engineering due to their excellent structure-property relationships. However, the potential can only be exploited if their structural integrity is ensured. This requires a fundamental understanding of the impact of imperfections that arise during additive manufacturing. Therefore, in the present study, the structure-property relationships of eight TPMS lattices, including their imperfections, are investigated experimentally and numerically. In particular, the focus is on biomimetic network TPMS lattices of the type Schoen I-WP and Gyroid, which are fabricated by laser powder bed fusion from the biocompatible alloy Ti-42Nb. The experimental studies include computed tomography measurements and compression tests. The results highlight the importance of process-related imperfections on the mechanical performance of TPMS lattices. In the numerical work, firstly the as-built morphology is artificially reconstructed before finite element analyses are performed. Here, the reconstruction procedure previously developed by the same authors is used and validated on a larger experimental matrix before more advanced calculations are conducted. Specifically, the reconstruction reduces the numerical overestimation of stiffness from up to 341% to a maximum of 26% and that of yield strength from 66% to 12%. Given a high simulation accuracy and flexibility, the presented procedure can become a key factor in the future design process of TPMS lattices.

The stiffness and toughness of topology optimised structures containing lattices under three-point bending is studied. A porosity constraint is introduced to control the proportion of lattice generated while optimising the beams for minimum compliance. A novel tetrahedron element-based lattice with tapered trusses and a near-isotropic elastic response is developed to accurately map the relative densities from topology optimisation to a 3D printable structure. Topology optimised solid structures (0 % porosity), used for benchmarking, are found to have high stiffness but can be susceptible to buckling. At the other extreme, structures comprising entirely of lattice (100 % porosity) are shown to have low initial stiffness and low residual toughness. An experimental parametric study reveals that porosity can be tailored between these two bounds to achieve both high stiffness and high residual toughness.

Additive manufacturing has provided the ability to manufacture complex structures using a wide variety of materials and geometries. Structures such as triply periodic minimal surface (TPMS) lattices have been incorporated into products across many fields due to their unique combinations of mechanical, geometric, and physical properties. Yet, the near limitless possibility of combining geometry and material into these lattices leaves much to be discovered. This article provides a dataset of experimentally gathered tensile stress-strain curves and measured porosity values for 389 unique gyroid lattice structures manufactured using vat photopolymerization 3D printing. The lattice samples were printed from one of twenty different photopolymer materials available from either Formlabs, LOCTITE AM, or ETEC that range from strong and brittle to elastic and ductile and were printed on commercially available 3D printers, specifically the Formlabs Form2, Prusa SL1, and ETEC Envision One cDLM Mechanical. The stress-strain curves were recorded with an MTS Criterion C43.504 mechanical testing apparatus and following ASTM standards, and the void fraction or “porosity” of each lattice was measured using a calibrated scale. This data serves as a valuable resource for use in the development of novel printing materials and lattice geometries and provides insight into the influence of photopolymer material properties on the printability, geometric accuracy, and mechanical performance of 3D printed lattice structures. The data described in this article was used to train a machine learning model capable of predicting mechanical properties of 3D printed gyroid lattices based on the base mechanical properties of the printing material and porosity of the lattice in the research article [1].

Advancements in additive manufacturing (AM) technology and three-dimensional (3D) modeling software have enabled the fabrication of parts with combinations of properties that were impossible to achieve with traditional manufacturing techniques. Porous designs such as truss-based and sheet-based lattices have gained much attention in recent years due to their versatility. The multitude of lattice design possibilities, coupled with a growing list of available 3D printing materials, has provided a vast range of 3D printable structures that can be used to achieve desired performance. However, the process of computationally or experimentally evaluating many combinations of base material and lattice design for a given application is impractical. This research proposes a framework for quickly predicting key mechanical properties of 3D printed gyroid lattices using information about the base material and porosity of the structure. Experimental data was gathered to train a simple, interpretable, and accurate kernel ridge regression machine learning model. The performance of the model was then compared to numerical simulation data and demonstrated similar accuracy at a fraction of the computation time. Ultimately, the model development serves as an advancement in ML-driven mechanical property prediction that can be used to guide extension of current and future models.

The use of lattice structure in the Design for Additive Manufacturing (DfAM) engineering practice offers the ability to tailor the properties (and therefore the response) of an engineered component independent of the material and overall geometry. The selection of a lattice topology is critical in maximizing the value of the lattice structure and its unique properties for the intended application. To support this, we have compiled a catalog of lattice structures from the literature that includes all Triply Periodic Minimal Surfaces (TPMS) for which a low-order Fourier series fit is known (so that they can be modeled and manufactured). We also include equations that do not directly correspond to known TPMS but do produce a triply periodic structure without sharp corners that would give rise to stress concentrations. This catalog includes images, elastic mechanical property data, and CAD models useful for the visualization, selection, and implementation of these lattice structures for any engineered structure.

Additive manufacturing of pure copper (Cu) via laser-powder bed fusion (L-PBF) is challenging due to the low energy absorptivity under infra-red laser. As a result, 3-dimensional architectures, known for excellent load-bearing and energy absorption capabilities, have not been fabricated in pure Cu, so far. This study, for the first time, Cu lattice structures are fabricated through laser-powder bed fusion (L-PBF) with green laser (λ = 515 nm). Structural and microstructural analysis confirm that the lattice structures consist of well-defined unit-cells and show dense microstructure. The deformation behavior is investigated under a wide range of strain rates from ∼0.001 /s to ∼1000 /s. The stress–strain curves exhibit a smooth and continuous deformation without any post-yield softening, which can be attributed to the intrinsic mechanical properties of Cu. Correlated with post-mortem microscopy examination, the rate-dependent deformation behavior of pure Cu lattice structures is investigated and rationalized. The current work suggests that the complex Cu architectures can be fabricated by L-PBF with green laser and are suitable for dynamic loading applications.

Lattice structures with graded composition and microstructure in function of position allow for a smooth transition and due to their combination of multiple desirable features show great prospects in various applications. This study describes the characteristics of Ni alloy-bronze composite lattice structures (CLS) which can be used for manufacturing slide bearings intended for operation under heavy loads. The CLS were fabricated via directed energy deposition method on a substrate of AISI 1045 structural steel. The basic microstructural characteristics as well as microhardness were analyzed to study the features of composite structures depending on the speed of the laser beam as well as the laser spot step. Operational tests of the studied CLS were carried out under different loads and lubrication conditions. It was confirmed that the CLS wear resistance is 5–12 times higher under dry friction conditions and ∼65 times higher under mixed lubrication conditions as compared to the initial Ni alloy and bronze. It was claimed that CLS tested and formed using modern directed energy deposition technology exhibit improved material and tribological characteristics. These results are important both from the standpoint of practical applications and future research.

Tunable energy absorption achieved through grading of lattice structures shows high potential to be used in lightweight cellular cores for energy absorbing structures. This study investigates structurally graded and multi-material lattices consisting of plate-based octet unit cells, under quasi-static compression, to assess their energy absorption ability. Variations in the structure and material compositions of the plate-lattice structures are achieved through changing the plate thickness and through changing the filament material along the lattice in the direction of applied compressive force. The compressive stress–strain behavior reveals a near 10% increase of specific energy absorption (SEA) in the plate thickness graded designs at higher strain compared to the baseline octet lattices. The multi-material arrangements significantly modified onset location of the structure collapse. Finite element models of the structures were developed, and good agreements with experimental results were observed. Effects of varying each of the unit cell geometric parameters were analyzed, and the high sensitivity to the plate inclination angle, which resulted in greater changes to the maximum stress values and control of the overall SEA, was identified. The results demonstrate the capacity to adapt the octet lattice structure design through additive manufacturing to better suit the expected load and application.

Metal polymer composites combining low density, high strength composites with highly ductile and tough metals have gained traction over the last few decades as lightweight and high-performance materials for industrial applications. However, the mechanical properties are limited by the interfacial bonding strength between metals and polymers achieved through adhesives, welding, and surface treatment processes. In this paper, a novel manufacturing process combining additive manufacturing and compression molding to obtain hybrid metal polymer composites with enhanced mechanical properties is presented. Additive manufacturing enabled deposition of polymeric material with fibers in a predetermined pattern to form tailored charge or preform for compression molding. A grade 300 maraging steel triangular lattice is first fabricated using AddUp FormUp350 laser powder bed system and compression overmolded with additively manufactured long carbon fiber-reinforced polyamide-6,6 (40% wt. CF/PA66) preform. The fabricated hybrid metal polymer composites showed high stiffness and tensile strength. The stiffness and failure characteristics determined from the uniaxial tensile tests were correlated to a finite element model within 20% deviation. Fractographic analyses was performed using microscopy to investigate failure mechanisms of the hybrid structures.

Porosity is considered to be one of the key factors affecting the structural properties of porous lattices, but in fact, pore size also plays an important role, and it has great potential to adjust pore size and porosity independently to improve structural properties. In this work, by adjusting the sheet thickness of the triply periodic minimal surface (TPMS) lattice structures and adjusting the height of the single row structure according to linear and constant laws, the TPMS lattice structures with given porosity and adjustable pore size are designed, and the mechanical response is investigated. Based on preparing samples by Ti6Al4V laser powder bed fusion, the results of the tests show that the elastic modulus ranges of linear change TPMS (LC-TPMS) and constant TPMS (C-TPMS) lattice structures are 3625.6 MPa–4575.1 MPa and 3820.0 MPa–4509.1 MPa, respectively. In the plateau stage, the LC-TPMS lattice structures have a longer and more stable plateau stage, higher yield stress and better energy absorption capacity than the C-TPMS lattice structures. The maximum energy absorption difference is 62.7 MJ/mm3 and the maximum energy absorption efficiency difference is 0.12. The LC-TPMS lattice structures can also obtain a larger damping ratio under larger compressive strain.

Metal-based additive manufacturing techniques offer the ability to produce complex, near net shape parts that would be impossible or prohibitively expensive to manufacture via traditional casting and machining methods. Low density lattice structures for lightweight construction are one such example. However, there currently are no well-developed guidelines for designing and reliably manufacturing these structures. Literature on the topic is fragmented and usually only covers a limited aspect of the complex relations between process parameters, microstructure, lattice geometry and mechanical properties. This work covers the edge case of small diameter struts manufactured from AlSi10Mg via Laser Powder Bed Fusion (L-PBF) using the single contour exposure strategy, which is necessary to ensure sufficient geometric accuracy. Various cubic strut-based lattice geometries are manufactured using four laser parameter combinations corresponding to different area energy densities and beam offsets. The influence of process parameters and heat treatment on the microstructure and mechanical properties is investigated. Results show that the microstructure of filigree lattice struts can be tailored by the selection of process parameters, resulting in either uniform or core–shell structures depending on the laser power, while the macroscopic mechanical properties are mainly determined by the lattice geometry and relative density.

Characterization of additively manufactured materials and structures is an ongoing effort for the advanced manufacturing community. This article will investigate an approach using resonant spectral ultrasound (RUS) to measure the effective elastic constants of an Octet Truss lattice and apply the results to continuum bases models representing the lattice regions in different structures. The study is focused on simple lattices structures fabricated from Ti5553 using a laser powder bed fusion process (LBPF). Solid and lattice samples are measured to determine RUS estimates for the elastic properties of the bulk material and the effective elastic properties of the lattice structure. The estimated elastic properties are then incorporated into 3d finite element models using a continuum approximation of the physical AM parts. Comparisons show good agreement between the experimentally measured eigen frequencies of the Ti5553 LBPF parts and the eigen frequencies calculated using the continuum approximations based on the effective RUS elastic properties. The current results suggest there is additional physics and geometrical effects that are accounted for in the RUS continuum approximation of the lattice that are not captured in the full 3d finite element model of the parts utilizing only the base material properties.

Lattice-type periodic metamaterials with beam-like struts have been extensively investigated in recent years thanks to the progress in additive manufacturing technologies. However, when lattice structures are subject to large deformations, computational simulation for design and optimization remains a major challenge due to complex nonlinear and inelastic effects, such as instabilities, contacts, rate-dependence, plasticity, or damage. In this contribution, we demonstrate for the first time the efficient and accurate computational simulation of beam lattices using a finite deformation 3D beam formulation with inelastic material behavior, instability analysis, and contacts. In particular, the constitutive model captures elasto-visco-plasticity with damage/softening from the Mullins effect. Thus, the formulation can be applied to the modeling of both stiffer metallic and more flexible polymeric materials. The approach is demonstrated and experimentally validated in application to additively manufactured lattice structures made from Polyamide 12 by laser sintering and from a highly viscous polymer by vat photopolymerization. For compression tests executed until densification or with unloading and at different rates, the beam simulations are in very good agreement with experiments. These results strongly indicate that the consideration of all nonlinear and inelastic effects is crucial to accurately model the finite deformation behavior of lattice structures. It can be concluded that this can be effectively attained using inelastic beam models, which opens the perspective for simulation-based design and optimization of lattices for practical applications.

Large or carcinogenic bone defects may require a challenging bone tissue scaffold design ensuring a proper mechanobiological setting. Porosity and biodegradation rate are the key parameters controlling the bone-remodeling process. PLA presents a great potential for geometrically flexible 3-D scaffold design. This study aims to investigate the mechanical variation throughout the biodegradation process for lattice-type PLA scaffolds using both experimental observations and simulations. Three different unit-cell geometries are used for creating the scaffolds: basic cube (BC), body-centered structure (BCS), and body-centered cube (BCC). Three different porosity ratios, 50 %, 62.5 %, and 75 %, are assigned to all three structures by altering their strut dimensions. 3-D printed scaffolds are soaked in PBS solution at 37 °C for 15, 30, 60, 90, and 120 days both unloaded and under dead load. Water absorption, weight loss, and compression stiffness are measured to characterize the first-stage degradation and investigate the possible influences of these parameters on the whole biodegradation process. The strength reduction stage of biodegradation is simulated by solving pseudo-first-order kinetics-based molecular weight change equation using FEA with equisized cubic (voxel-like) elements. For the first stage, mechanical load does not have a statistically significant effect on biodegradation. BCC with 62.5 % porosity shows a maximum water absorption rate of around 25 % by the 60th day which brings an advantage in creating an aquatic environment for cell growth. Results indicate a significant water deposition inside almost all scaffolds and water content is determined to be the main reason for the retained or increased compression stiffness. A distinguishable stiffness increase in the initial degradation process occurs for 75 % porous BC and 50 % porous BCC scaffolds. Following the quasi-stable stage of biodegradation, almost all scaffolds lost their rigidity by around 44-48 % within 120 days based on numerical results. Therefore, initial stiffness increase in the quasi-stable stage of biodegradation can be advantageous and BCC geometry with a porosity between 50% and 62 % is the optimum solution for the whole biodegradation process., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Huseyin Lekesiz reports financial support was provided by Scientific and Technological Research Council of Turkey. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Additive manufacturing for fabrication of patient-specific oral and maxillofacial implants enables optimal fitting, significantly reducing surgery time and subsequent costs. However, it is still common to encounter hardware- or biological-related complications, specifically when radiation treatment is involved. For mandibular reconstruction plates, irradiated patients often experience plate loosening and subsequent plate exposure due to a decrease in the vascularity of the irradiated tissues. We hypothesize that an acceleration of the bone ingrowth prior to radiation treatment can increase the survival of such plates. In this work, a new design of a mandibular reconstruction plate is proposed to promote osseointegration, while providing the necessary mechanical support during healing. In this regard, six different Triply Periodic Minimal Surface (TPMS) structures were manufactured using laser-powder bed fusion. Three-point bending and in-vitro cell viability tests were performed. Mechanical testing demonstrated the ability for all structures to safely withstand documented biting forces, with favorable applicability for the Gyroid structure due its lower flexural modulus. Finally, cell viability tests confirmed high cell proliferation rate and good cell adhesion to the surface for all TPMS structures. Overall, the new design concept shows potential as a viable option for plates with improved functionality and higher survival rate., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Ceramic lattices hold great potential for bone scaffolds to facilitate bone regeneration and integration of native tissue with medical implants. While there have been several studies on additive manufacturing of ceramics and their osseointegrative and osteoconductive properties, there is a lack of a comprehensive examination of their mechanical behavior. Therefore, the aim of this study was to assess the mechanical properties of different additively manufactured ceramic lattice structures under different loading conditions and their overall ability to mimic bone tissue properties. Eleven different lattice structures were designed and manufactured with a porosity of 80% using two materials, hydroxyapatite (HAp) and zirconium dioxide (ZrO 2 ). Six cell-based lattices with cubic and hexagonal base, as well as five Voronoi-based lattices were considered in this study. The samples were manufactured using lithography-based ceramic additive manufacturing and post-processed thermally prior to mechanical testing. Cell-based lattices with cubic and hexagonal base, as well as Voronoi-based lattices were considered in this study. The lattices were tested under four loading conditions: compression, four-point bending, shear and tension. The manufacturing process of the different ceramics leads to different deviations of the lattice geometry, hence, the elastic properties of one structure cannot be directly inferred from one material to another. ZrO 2 lattices prove to be stiffer than HAp lattices of the same designed structure. The Young's modulus for compression of ZrO 2 lattices ranges from 2 to 30GPa depending on the used lattice design and for HAp 200MPa to 3.8GPa. The expected stability, the load where 63.2% of the samples are expected to be destroyed, of the lattices ranges from 81 to 553MPa and for HAp 6 to 42MPa. For the first time, a comprehensive overview of the mechanical properties of various additively manufactured ceramic lattice structures is provided. This is intended to serve as a reference for designers who would like to expand the design capabilities of ceramic implants that will lead to an advancement in their performance and ability to mimic human bone tissue., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

The emergence of additive manufacturing technology has enabled the fabrication of advanced structures with intricate geometric topologies. However, additive manufacturing induces geometric defects in as-printed structures which may result in deviation from the parent material’s properties. The defects and impaired material properties greatly influence the performance of the fabricated structure. In this paper, the effect of build angle is investigated. The angle-dependency for the geometric defect distribution characteristics is verified through X-ray tomography. The mathematical relationship between the parent material’s properties and the build angle is established. A numerical model is developed for predicting the mechanical performance of laser powder bed fusion fabricated lattice structures proposed by using the experimental results. The positioning geometric defects are introduced into this model to achieve higher predicting accuracy. This work proposes a reliable and low-cost numerical analysis method based on the angle dependence and helps in predicting the mechanical performance of additive-manufactured complex three-dimensional lattice structures.

Over the past decades, additive manufacturing technology has replaced the conventional methods of production of lattice structures such as investment casting, expanded metal sheet and metallic wire assembly. However, this technology still requires more development in order to enable the application of lattice structures in lightweight load bearing structures. The main challenge lies in the structural integrity of additively manufactured lattice structures which holds back exploiting their lightweight potential. While recent research focuses on the influence of process parameters on the mechanical behaviour of lattice structures, less attention is given to geometrical notches issued from sharp edges induced by the structural design. This contribution handles the effect of geometrically induced notches in truss lattice structures. The static mechanical properties of truss-like unit cells are compared to, on the one hand, the common design solution which consists in implementing a fillet radius and, on the other hand, two notch stress optimization methods inspired from existing methods for two-dimensional notches. The comparison encompasses the analytical development of the aforementioned methods as well as their numerical verification and experimental validation for additively manufactured lattices made of AlSi10Mg. Resulting recommendations on design guidelines for improved mechanical properties of truss lattice structures are then discussed.

Additive manufacturing overcomes the restrictions of classical manufacturing methods and enables the production of near-net-shaped, complex geometries. In that context, lattice structures are of high interest due to their superior weight reduction potential. AlSi10Mg is a well-known alloy for additive manufacturing and well suited for such applications due to its high strength to material density ratio. It has been selected in this study for producing bulk material and complex geometries of a strut-based lattice type (rhombic dodecahedron). A detailed characterisation of as-built and heat-treated specimens has been conducted including microstructural analyses, identification of imperfections and rigorous mechanical testing under different load conditions. An isotropic elastic–plastic material model is deduced on the basis of tension test results of bulk material test specimens. Performed experiments under compression, shear, torsion and tension load are compared to their virtual equivalents. With the help of numerical modelling, the overall structural behaviour was simulated using the detailed lattice geometry and was successfully predicted by the presented numerical models. The discussion of the limits of this approach aims to evaluate the potential of the numerical assessment in the modelling of the properties for novel lightweight structures.

Lattice structures have great potential for lightweight additively manufactured parts. This paper presents a bio-inspired functionally graded lattice structure optimisation approach for compliance minimisation of statically loaded structures. Topology optimisation determines the optimal relative density distribution within a design space and the associated strain fields. A lattice structure is then generated within this design space, comprised of trusses aligned with principal strain trajectories. The trusses have a rectangular cross-section, resulting in three size variable per node during the final sizing step. A minimum feature size is implemented so that the designs are suited to the particular additive manufacturing process print resolution. The presented approach is further demonstrated to efficiently solve problems with multiple load cases and produce lattice topologies that mimic those found in bone. The optimised lattice structure examples presented are on average 12% less stiff in comparison to a conventional SIMP topology optimisation approach. However, they are well suited to multifunctional applications such as heat transfer where the surface area is increased by an average of 94%. The optimised lattice structures are also shown to be able to eliminate additive manufacturing support structure requirements.

Additive Manufacturing (AM) enables the generation of complex geometries and controlled internal cavities that are so interesting for the biomedical industry due to the benefits they provide in terms of osseointegration and bone growth. These technologies enable the manufacturing of the so-called lattice structures that are cells with different geometries and internal pores joint together for the formation of scaffold-type structures. In this context, the present paper analyses the feasibility of using diamond-type lattice structures and topology optimisation for the re-design of a dental implant. Concretely, a new ultra-short implant design is proposed in this work. For the manufacturing of the implant, digital light processing additive manufacturing technique technology is considered. The implant was made out of Nano-zirconia and Nano-Calcium Silicate as an alternative material to the more common Ti6Al4V. This material combination was selected due to the properties of the calcium-silicate that enhance bone ingrowth. The influence of different material combination ratios and lattice pore sizes were analysed by means of FEM simulation. For those simulations, a bio-material bone-nanozirconia model was considered that represents the final status after the bone is integrated in the implant. Results shows that the mechanical properties of the biocompatible composite employed were suitable for dental implant applications in dentistry. Based on the obtained results it was seen that those designs with 400 μm and 500 μm pore sizes showed best performance and led to the required factor of safety., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

A porous lattice structure with highly controllable mechanical properties, low weight, and high strength is the most promising option for many fields, such as the aerospace, automobile, and biomedical industries. However, the most common and critical issue is the excessively high stress concentration at the struts’ nodes when the lattice structure is loaded. Thus, a curving lattice design strategy is proposed, maintaining a light structure, through which either a circular or elliptical arc is used in the lattice struts to obtain new forms of curving lattice structures. By establishing theoretical models and preparing samples by laser powder bed fusion (L-PBF), combined with scanning electron microscopy (SEM), quasi-static uniaxial compressive experiments, finite element analysis (FEA), and Gibson-Ashby models, excellent results were obtained. The stress distribution of the original under the loads was altered in the curving lattice structure and the stress concentration at the nodes of the struts was effectively relieved, dramatically improving its mechanical properties. Compared with the original structure, the specific elastic modulus and specific compressive strength of curving lattice structures were maximally increased by 213.7% and 126.2%, respectively. Meanwhile, the curving lattice structure had a superior energy absorption capacity, with a significant increase of 92.9%.

Recent orthopaedic implant alloy design has focused on β-type Ti alloys, as the body centred cubic (BCC) crystal structure has the tendency to be characterised by a low elastic modulus. Nevertheless, the currently most used metal is Ti-6Al-4V, which mainly retains a hexagonal closed packed (HCP) crystal structure when produced by additive manufacturing. The benefits and disadvantages of the mechanical response of each crystal structure for implant applications is yet to be explored. Utilising the TiTa alloy system, low modulus Ti25Ta and Ti65Ta lattices were additively manufactured with opposing crystal structures of α′ martensite (HCP) and β grains (BCC). The lattices showed similar tensile, compressive and high cycle fatigue behaviour, indicating that the α' alloy was mechanically equal to the β alloy for implant applications. The mechanical properties of both the TiTa lattices were also superior to identically manufactured lattices in Ti-6Al-4V in both as-built and heat treated conditions.

Various manufacturing defects are known to have significant impact on the mechanical properties of lattice structures. Therefore, defects-embedded FE models are essential for accurate mechanical prediction. However, previous studies often focused on the investigation of complete lattice structure models. As a result, the comprehensive investigation of defects in a single strut remained elusive. The present study investigated five different defects on a single strut, namely undersizing/oversizing, diameter variation, offset of the cross section, internal voids, and local mechanical properties. It was found that the undersizing and oversizing were the primary factor affecting the discrepancy between experiments and numerical predictions for most cases. The diameter variation and offset of the cross section were seen to be dominant for small struts, especially those with 45° build orientation. Furthermore, even though the onset of localization could be observed due to the presence of voids, they had a negligible impact on elastic and initial yielding responses, partly because of their low volume fraction. Besides, the effect from geometrical inaccuracies and varied properties were mostly comparable although that of the former was more dominant in smaller samples. In addition, the sensitivity from the µCT voxel size affected both global behaviors and localization.

Metal additive manufacturing involves manufacturing techniques that add material to produce metallic components, typically layer by layer. The substantial growth in this technology is partly driven by its opportunity for commercial and performance benefits in the aerospace industry. The fundamental opportunities for metal additive manufacturing in aerospace applications include: significant cost and lead-time reductions, novel materials and unique design solutions, mass reduction of components through highly efficient and lightweight designs, and consolidation of multiple components for performance enhancement or risk management, e.g. through internal cooling features in thermally loaded components or by eliminating traditional joining processes. These opportunities are being commercially applied in a range of high-profile aerospace applications including liquid-fuel rocket engines, propellant tanks, satellite components, heat exchangers, turbomachinery, valves, and sustainment of legacy systems. This paper provides a comprehensive review of metal additive manufacturing in the aerospace industry (from industrial/popular as well as technical literature). This provides a current state of the art, while also summarizing the primary application scenarios and the associated commercial and technical benefits of additive manufacturing in these applications. Based on these observations, challenges and potential opportunities are highlighted for metal additive manufacturing for each application scenario.

In this work, a new hierarchical lattice design is proposed by replacing the original straight beams of face-centered cubic (FCC) lattice with a string of higher-level circular beams from the perspective of forming more plastic hinges to improve the energy absorption capacity. The quasi-static compression behavior of our proposed lattice is thoroughly investigated by finite element simulation, theoretical modeling and experimental testing. The experimental specimens made from 316L steel are additively manufactured using the selected laser melting technique. Satisfactory agreement is achieved between the theoretically, numerically and experimentally obtained SEA. It indicates that the proposed lattices have better energy absorption than the conventional FCC lattice. Parametric studies are carried out to investigate the influence of various geometric parameters and indicate that the specific energy absorption and the crushing force efficiency can be simultaneously enhanced by the proposed hierarchical design with proper number of higher-level circular beams. In addition, the auxetic effect is exhibited by the new lattice structures, in accordance with the enhanced energy absorption properties.

The effects of the electron beam (EB) continuity on the microstructures and mechanical properties of titanium lattice structures with produced by EB additive manufacturing were studied. Continuous line and discontinuous spot scans were applied for the EB continuity. The porous structures produced with the continuous line scans had lower defect densities than those produced with discontinuous spot scans. Most defects of the continuous line scans had spherical morphologies, whereas non-spherical defects formed in the porous structure produced with discontinuous spot scans because of the availability of sufficient heat for melting the powder. The microstructures were composed of an α-titanium matrix, martensitic α′ phases, and elongated FeTi4 phases on the grain boundaries. Furthermore, the atom probe tomography results showed that the FeTi4 phase had a network structure with a diameter of 5 nm after the continuous line scan, which enhanced the compressive strength. The compressive strength and elastic modulus of the porous structures produced with the continuous line scan were more than 400 MPa and 11 GPa, respectively. Despite the high porosity, continuous line scans are preferable for achieving high compressive strengths with low elastic moduli for biomedical devices.

Oral cavity tumors are a prevalent cause of mandible reconstruction surgeries. The mandible is vital for functions like oralization, respiration, mastication, and deglutition. Current mandible reconstruction methods have low success rates due to complications like plate fracture or exposure, infections, and screw loosening. Autogenous bone grafts are commonly used but carry the risk of donor region morbidity. Despite technological advances, an ideal solution for mandible reconstruction remains elusive. Additive manufacturing in medicine offers personalized prosthetics from patient-specific medical images, allowing for the creation of porous structures with tailored mechanical properties that mimic bone properties. This study compared a commercial reconstruction plate with a lattice-structured personalized prosthesis under different biting and osseointegration conditions using Finite Element Analysis. Patient-specific images were obtained from an individual who underwent mandible reconstruction with a commercial plate and suffered from plate fracture by fatigue after 26 months. Compared to the commercial plate, the maximum von Mises equivalent stress was significantly lowered for the personalized prosthesis, hindering a possible fatigue fracture. The equivalent von Mises strains found in bone were within bone maintenance and remodeling intervals. This work introduces a design that doesn't require grafts for large bone defects and allows for dental prosthesis addition without the need for implants., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The focus of this research is to create a methodology to systematically generate spatially-varying, periodic, cellular microstructures that are tailored to attain optimized performance of the macrostructure. The unit cell lattice is represented by Fourier series expansions, and the corresponding amplitudes and phase spectrum are obtained. Then, the material distribution (topology) and orientation of each cell (morphology) are optimized for multiple load cases. The phase of the spatial harmonics is updated based on the optimized orientation, and the analog response is thresholded with the optimized material distribution to find the binary lattices. The framework is tested for three types of lattices with various periodicities. The square cell with a rectangular hole shows the exploitation of the cell's orthotropic properties for structures subjected to a single load case; the triangular cell with the triangular lattice depicts the applicability of other types of cells and lattices to transfer shear for the structures subjected to multiple load cases; and the square cell with pentagonal lattices shows the versatility of the framework. An optimized triangular cellular solid is additively manufactured, and it is validated experimentally that 12% higher stiffness and 57% higher strength can be achieved compared to the conventional topology optimization design.

Laser powder bed fusion enables the fabrication of complex components such as thin-walled cellular structures including lattice or honeycomb structures. Numerous manufacturing parameters are involved in the resulting properties of the fabricated component and a material and machine-dependent process window development is necessary to determine a suitable process map. For cellular structures the thickness, which correlates with the process parameters, directly influences the mechanical properties of the component. Thus, dimensionless scaling laws describing the correlation between strut thickness, process parameters, and material properties enable predictive lattice structure design for laser powder bed fusion. This contribution develops material independent dimensionless allometric scaling laws for both single track and contour exposure to enable process-driven design of lattice structures in laser powder bed fusion. The theory derived with dimensional analysis is validated for the powder alloys stainless steel alloy 1.4404, nickel alloy 2.4856, aluminum alloy AlSi10Mg and Scalmalloy AlMgSc. The results can be used for the process-driven design of lattice structures and dense material obtaining high precision in the micrometer range or economic production with high melt pool widths.

A new parametric method for the design of Voronoi-based lattice porous structures is proposed in this paper. First, the functional relationship between the porosity p, the number of seed points n, and the beam radius r is established. The design space is then divided into individual unit cells, and the seed points and beam radius values of each unit cell are calculated. In each unit cell, Voronoi tessellation is used to generate uniformly distributed seed points. Finally in the design space, all seed points are Voronoi tessellated globally, and the edges are cylindered with corresponding beam radius values. With this design method, not only can the lattice structures with uniform or graded distribution of porosity be generated, but the customized lattice structures can also be generated according to the porosity of each unit cell. Through the analysis of model data, it is verified that the uniform distribution of seed points in this paper is stable and the porosity of the model is consistent with the design value. The distribution of pore spheres between pores is used to illustrate that the lattice porous structures designed in this paper is globally controllable and locally uniform.