Search Results (358)

Lattice structures are lightweight architected materials particularly suitable for aerospace and automotive applications due to their ability to combine mechanical strength with reduced mass. Among various topologies, Body-Centered Cubic (BCC) lattices are widely employed for their geometric regularity and favorable strength-to-weight ratio. Advances in Additive Manufacturing (AM) have enabled the precise and customizable fabrication of such complex architectures, reducing material waste and increasing design flexibility. This study investigates the low-velocity impact behavior of two polylactic acid (PLA)-based BCC lattice panels differing in strut diameter: BCC1.5 (1.5 mm) and BCC2 (2 mm). Experimental impact tests and finite element simulations were performed to evaluate their energy absorption () capabilities. In addition to conventional global performance indices, a dimensionless parameter, is introduced to quantify the ratio between local plastic indentation and global displacement, allowing for a refined characterization of deformation modes and structural efficiency. Results show that BCC1.5 absorbs more energy than BCC2, despite the latter’s higher stiffness. This suggests that thinner struts enhance energy dissipation under dynamic loading. Despite minor discrepancies, numerical simulations provide accurate estimations of and support the robustness of the index within the examined configuration, highlighting its potential to deformation heterogeneity. Full article

Lattice structures have been widely studied in various fields due to their lightweight and high-energy absorption capabilities. In this study, we propose the use of lattice structures in the design of sports protective equipment for contact sports athletes. A total of six specimens were additively manufactured either with a bending-dominated rhombic dodecahedron (RD) structure or stretch-dominated re-entrant (RE) structure. Elastic resin was used to investigate the specimens’ compressive strength and energy absorption, impact reduction, and flexural properties in comparison with those of conventional foam and rigid polyethylene (PU). Despite having a lower relative density, the RE structure exhibits greater stiffness, showing up to 40% greater hardness and averaging 30.5% higher bending rigidity compared with the RD structure. However, it unexpectedly shows less stability and strength under uniaxial loading, which is 3 to 6 times weaker when compared with the non-auxetic RD structure. Although conventional PU has higher loading than 3D-printed lattices, the lattice shows excellent bendability, which is only 1.5 to 3 times stiffer than that of foam. The 3D-printed lattice in this study shows an optimal improvement of 43% in terms of impact absorption compared with foam and a 2.3% improvement compared with PU. Amongst the six different unit cell dimensions and structures studied, the RD lattice with a cell size of 5 mm is the most promising candidate; it has superior elasticity, compressive strength, and impact resistance performance whether it is under low- or high-impact conditions. The findings of this study provide a basis for the development of 3D-printed lattice sports protective chest equipment, which is more comfortable and offers improved protection for contact sports players. Full article

In recent years, significant advancements have been made in the field of design for additive manufacturing (DfAM). These advancements have focused on key aspects such as topology optimization (TO), generative design (GD), lattice structures, and AI-based algorithms. This paper presents a methodology for developing custom Grasshopper^® algorithms to create strut-based, gradient, and conformal lattice structures. Two test geometries were devised and imported into Grasshopper^®, and different lattice structures with varying settings, such as conformity, lattice topology, and strut diameter gradient and cell size gradient, were generated and manufactured. A series of experiments was conducted to assess the impact of input parameters on the formation of lattice structures, their performance in three-point bending tests, and their effect on functionality, applicability, and usability. The experimental investigation yielded clear findings regarding the usability and functionality of the proposed algorithm. However, the findings indicate that although the overall process is usable, improvements are required to streamline the algorithm in order to avoid geometry generation errors and to make it more user-friendly. This approach presents a low-cost, customizable alternative to commercial lattice generation tools, with direct integration in Rhino 8 and Grasshopper^®. Full article

Advances in additive manufacturing (AM) have revolutionized various sectors, including aerospace engineering, where the use of lattice structures has enabled the development of lightweight high-performance components with optimized mechanical properties. Building on these engineering principles, this study explores the application of aerospace-derived lattice design strategies to the biomedical field, specifically for the replication of human lung alveolar structures. The objective is to create anatomically accurate 3D-printed lung models suitable for surgical planning. Finite element analyses have been conducted using a CAD model of adult lungs, including the application of lattice structures generated through nTopology software, to evaluate the elasticity and density, critical for simulating lung mechanics. A preliminary prototype has been produced using stereolithography and flexible resin, showing the potential for realistic tactile feedback. Full article

Selective laser melting (SLM) enables the production of complexly shaped metals with programmable mechanical responses, yet most lattice studies still rely on a single unit cell and a simple columnar build, severely restricting performance improvements. Here, we examine how combining distinct unit cells and rearranging them within the build volume affects the compressive behavior of SLM Corrax maraging stainless steel lattice structures. Three designs are additively manufactured as follows: a columnar cubic-FCCZ lattice, an alternating cubic and FCCZ lattice, and a hybrid lattice (cubic+FCCZ unit cell). In situ 2D digital image correlation (DIC) and finite element analysis (FEA) are used to resolve full-field strain evolution and failure modes under quasi-static compression. The hybrid lattice achieves the highest first maximum compressive strength (418 ± 5.78 MPa) and energy absorption (128.5 ± 6.83 MJ/m³), with its specific energy absorption (44.2 ± 1.48 kJ/kg) outperforming that of the columnar cubic-FCCZ lattice and alternating cubic and FCCZ lattice by 21.76% and 8.07%, respectively. The enhanced performance is attributed to the more uniform stress distribution and delayed shear band localization afforded by the hybrid lattice. These findings show that simultaneously optimizing unit cell geometry and arrangement can significantly expand the design space of metal lattices and provide a practical approach to improving the compressive strength and energy absorption capacity of load-bearing SLM components. Full article

This review paper deals with Triply Periodic Minimal Surfaces (TPMS) and lattice structures as a new generation of heat exchangers. Especially, their manufacturing is becoming feasible with technological progress. While some intricate structures are fabricated, challenges persist concerning manufacturing limitations, cost-effectiveness, and performance under transient operating conditions. Studies reported that these complex geometries, such as diamond, gyroid, and hexagonal lattices, outperform traditional finned and porous materials in thermal management, particularly under forced and turbulent convection regimes. However, TPMS necessitates the optimization of geometric parameters such as cell size, porosity, and topology stretching. The complex geometries enhance uniform heat exchange and reduce thermal boundary layers. Moreover, the integration of high thermal conductivity materials (e.g., aluminum and silver) and advanced coolants (including nanofluids and ethylene glycol mixtures) further improves performance. However, the drawback of complex geometries, confirmed by both numerical and experimental investigations, is the critical trade-off between heat transfer performance and pressure drop. The potential of TPMS-based heatsinks transpires as a trend for next-generation thermal management systems, besides identifying key directions for future research, including design optimization, Multiphysics modeling, and practical implementation. Full article

The reliable experimental characterization of architected lattice materials under cyclic loading requires accurate fixture systems that ensure proper load transfer without introducing parasitic effects. This study presents the design and validation of testing fixtures optimized using density-based topological optimization techniques for performing cyclic load tests on lattice structures. The supports were manufactured with PLA filaments and evaluated using finite element simulation and experimental testing. The results show that the final design achieved a safety factor of 4.25, significantly improving on the initial value of 2.08. Likewise, the optimized supports showed reduced deformations by around 80% compared to the machine clamps, ensuring rigid and reliable stress transfer. In particular, while the metal structure of the test system showed deformations of several millimeters, the optimized PLA supports recorded displacements around 0.73 mm, confirming that they remain virtually rigid and ensure correct transmission of forces to the Kelvin-type structure. These findings confirm the viability of using PLA as an alternative to conventional metal devices in fixtures for mechanical testing of lattice materials. Full article

Hierarchically porous polymers can unite macro-scale architected voids with micro-scale pores, enabling unique combinations of low density, high surface area, and controlled transport properties that are difficult to achieve with traditional methods. This review outlines the current advancements in creating such multiscale architectures using fused filament fabrication (FFF), the most widely used polymer additive manufacturing technique. Unlike earlier reviews that consider lattice architectures and foaming chemistries separately, this work integrates both within a single analysis. It begins with an overview of FFF fundamentals and how process parameters affect macropore formation. Design strategies for achieving macroporosity (≳100 µm) with a single thermoplastic are presented and categorized: 2D infill patterns, strut-based lattices, triply periodic minimal surfaces (TPMS), and Voronoi structures, along with functionally graded approaches. The discussion then shifts to functional filaments incorporating chemical or physical blowing agents, thermally expandable or hollow microspheres, and sacrificial porogens, which create microporosity (≲100 µm) either in situ or through post-processing. Each material approach is connected to case studies that demonstrate its application. A comparative analysis highlights the advantages of each method. Key challenges such as viscosity control, thermal gradient management, dimensional instability during foaming, environmental concerns, and the absence of standardized porosity measurement techniques are addressed. Finally, emerging solutions and future directions are explored. Overall, this review provides a comprehensive perspective on strategies that enhance FFF’s capability to fabricate hierarchically porous polymer structures. Full article

Free form fabrication (FFF), also known as fused deposition modeling (FDM), is a widespread and accessible method for prototyping. Parts a with lattice structure having functional roles as mechanism elements is becoming more common. In the research field, the mechanical characteristics as well as optimization methods for manufacturing these parts are major points of interest. One of the major aspects of FFF is part orientation during print, as it has influence over a wide range of variables, from tensile strength to surface quality and material consumption. For parts with a lattice structure, the printing orientation is important not only as a factor that influences the characteristics of the part itself, but also as a factor that determines the support requirements. However, due to the complex lattice structure, removing supports from these parts can be a challenging task. This study focuses on analyzing the reliability of available CAD optimization methods for FFF pre-processing. The analysis is performed using the Design for Additive Manufacturing module included in the Siemens NX software, version NX2406. The efficiency of CAD optimization was observed by taking into account the material consumption, printing times, surface quality, and support requirements. The study methods were based on the comparative analysis approach. The case studies used for the comparative analysis consider two-part inner structures: the solid structure approach with a rectilinear infill and the lattice structure approach. Full article

Additive manufacturing (AM) developments have been strongly driven by the ability of AM to improve the strength-to-weight ratios of structures, in contrast to traditional manufacturing methods, heavily supported by lattice structures. These motivations have persisted with the development of large-scale additively manufactured structures, which can offer more flexibility in manufacturing location and can often be faster than traditional manufacturing. However, current large-scale AM methods are often limited by their precision in order to maintain speed, constraining the method to manufacturing simple structures and often avoiding lattices altogether. This work proposes a mathematical framework for defining an equation-based lattice that splits the lattice into (1) build direction and (2) planar components such that their design can be altered to address AM methods restricted to three degrees of freedom. The framework is applied against a class of lattices called triply periodic minimal surfaces, which are represented using implicit equations, and it is shown that this approach allows for their use in large-scale AM technologies and enables further design control for small-scale AM design. Full article

This study investigates the influence of geometric parameters of a gyroid lattice structure on the thermal performance of internal cooling channels relevant to gas turbine blade design. Various gyroid configurations were analyzed using CFD simulations in ANSYS CFX to evaluate heat transfer effectiveness (Nusselt number), cooling flow penetration depth (cooling depth coefficient), and aerodynamic losses (pressure drop and drag coefficient). A series of simulations were conducted, varying lattice wall thickness, structure period, and Reynolds number, followed by the development of regression models to identify key trends. Experimental verification was carried out using 3D printed samples tested on a specially assembled aerodynamic test rig. Results confirmed the existence of an optimal lattice density, providing a favorable balance between heat transfer and pressure losses. The study highlights the high potential of gyroid TPMS structures for turbine blade cooling systems, where additive manufacturing enables complex internal geometries unattainable by traditional methods. The research demonstrates the practical feasibility and thermo-hydraulic advantages of lattice-based cooling channels and provides accurate predictive models for further optimization of turbine blade designs under high-temperature turbomachinery conditions. Full article

While crystal-inspired design has become a promising strategy for developing advanced mechanical metamaterials, the specific role of individual grain boundary interfaces on the macroscopic mechanical properties has remained unclear. This study aims to elucidate the importance of this interface by designing, fabricating, and testing bicrystal-inspired lattice structures. Using the Coincident Site Lattice (CSL) theory, we modeled various Σ5 tilt grain boundaries in a bicrystal configuration. These structures were fabricated from SUS316L powder using a powder bed fusion (PBF) additive manufacturing process. Compression tests revealed that the presence and type of the macroscopic “grain boundary” interface are critical determinants of the mechanical response, with symmetric bicrystal structures exhibiting a distinct two-stage collapse. More importantly, by engineering the fine structure of the interface itself, such as the density of connecting struts, the mechanical properties can be precisely tuned, achieving a systematic variation in yield strength from 9.1 MPa to 11.5 MPa. This work clarifies the crucial role of interfacial structure in crystal-inspired metamaterials and provides a clear design principle for creating lightweight, damage-tolerant structures with programmable mechanical responses. Full article

The present study offers a systematic review of the current state of research on lattice structures manufactured by additive technologies for biomedical applications, with the aim of identifying common patterns, such as the use of triply periodic minimal surfaces (TPMS) for bone scaffolds, as well as technological gaps and future research opportunities. Employing the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) methodology, the review process ensures methodological rigor and replicability across the identification, screening, eligibility, and inclusion phases. Additionally, PRISMA was tailored by prioritizing technical databases and engineering-specific inclusion criteria, thereby aligning the methodology with the scope of this field. In recent years, a substantial surge in interdisciplinary research has underscored the promise of architected porous structures in enhancing mechanical compatibility, fostering osseointegration, and facilitating personalized medicine. A growing body of literature has emerged that explores the optimization of geometric features to replicate the behavior of biological tissues, particularly bone. Additive manufacturing (AM) has played a pivotal role in enabling the fabrication of complex geometries that are otherwise unachievable by conventional methods. The applications of lattice structures range from permanent load-bearing implants, commonly manufactured through selective laser melting (SLM), to temporary scaffolds for tissue regeneration, often produced with extrusion-based processes such as fused filament fabrication (FFF) or direct ink writing (DIW). Notwithstanding these advances, challenges persist in areas such as long-term in vivo validation, standardization of mechanical and biological testing, such as ISO standards for fatigue testing, and integration into clinical workflows. Full article

The use of additive manufacturing technology for the lightweight design of complex lattice structures is becoming increasingly popular, but research on lattice structure design and strength evaluation still relies on the visual comparison of stress distributions and lacks quantitative assessment data. Given this perspective, this study explored the effects of structural parameters (relative density, cell size, and sample size) on the compressive strength of diamond lattice structures prepared by Stereolithography (SLA) and revealed the underlying mechanisms through stress distribution simulations and the calculation of characteristic stress distribution parameters (structural efficiency and stress concentration coefficient). The results showed that a greater relative density can increase structural efficiency, but it hardly affects the stress concentration coefficient, and smaller cell sizes and larger sample sizes increase the stress concentration coefficient without affecting the structural efficiency. Lattice structures with a greater relative density, higher structural efficiency, and a larger stress concentration coefficient exhibit higher compressive strength according to the lattice strength formula, which indicates that lattice strength is determined by the product of structural efficiency, stress concentration coefficient, relative density, and material strength. The relevant conclusions could guide the analysis of lattice stress distribution and the design of lattice structures. Full article

This study investigates the microstructural evolution and mechanical response of an additively manufactured (PBF-LB/M) AlSi10Mg alloy subjected to severe plastic deformation via two passes of twist channel angular pressing (TCAP). Processing was conducted using Route Bc, with the first pass at 150 °C and the second at 250 °C. For the first time, the evolution from the initial hierarchical AM structure to a refined state was characterized in high-fidelity detail using a novel EBSD detector. The two-pass process transformed the initial structure into a heterogeneous, bimodal microstructure existing in a non-equilibrium state, characterized by a high fraction of low-angle grain boundaries (63%) and significant internal lattice distortion. The mechanical properties were dictated by the processing temperature: a single pass at 150 °C induced work hardening, increasing the yield strength from 450 MPa to 482 MPa. Conversely, the second pass at an elevated temperature of 250 °C promoted significant dynamic recovery. This led to a decrease in yield strength to 422 MPa but concurrently resulted in a substantial increase in ultimate compressive strength to 731 MPa. Full article