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Frontier environments – such as battlefields, hostile territories, remote locations, or outer space – drive the need for lightweight, deployable structures that can be stored in a compact configuration and deployed quickly and easily in the field. This paper seeks to introduce the concept of lattice skins is introduced to enable the design, solid freeform fabrication (SFF), and deployment of customizable structures with nearly arbitrary surface profile and lightweight multi‐functionality.

Using Duraform^® FLEX material in a selective laser sintering machine, large deployable structures are fabricated in a nominal build chamber by decomposing them into smaller parts. Before fabrication, lattice sub‐skins are added strategically beneath the surface of the part. The lattices provide elastic energy for folding and deploying the structure or constrain expansion upon application of internal air pressure. Nearly, arbitrary surface profiles are achievable and internal space is preserved for subsequent usage.

A set of virtual and physical prototypes are presented, along with the computational modeling approach used to design them. The prototypes provide proof of concept for lattice skins as a deployment mechanism in SFF and demonstrate the effect of lattice structures on deployed shape.

The research findings demonstrate not only the feasibility of a new deployment mechanism‐based on lattice skins – for deploying freeform structures, but also the potential utility of SFF techniques for fabricating customized deployable structures.

A new lattice skin mechanism is introduced for deploying structures with nearly arbitrary surface profiles and open, usable, internal space. Virtual and physical prototypes are introduced for proof of concept, along with an optimization approach for automated design of these structures.

The purpose of this paper is to introduce, for the first time, the topology optimization method into the lattice structure configuration design for rapid casting patterns.

A structural topology optimization procedure in combination with thermo‐mechanical finite element analysis for the lattice structure configuration design has been developed.

A new mixed stress‐compliance optimization model is proposed for the strength and rigidity design. Numerical modeling about the mathematical formulation of the objective function and design constraints is established and an optimal material layout inside a given domain of the stereolithography (SL) resin pattern is found.

Various optimal results of lattice structure configurations are obtained numerically. By comparing the optimal designs with the existing lattice structure configurations, the newly obtained designs have shown better performances both in reducing the stress in the ceramic shell and in maintaining the stiffness of the SL pattern.

The objective of this paper is to identify suitable lattice structure patterns for the design of porous bone implants manufactured using additive manufacturing.

The study serves to compare and analyse the mechanical behaviours between cubic and octet-truss gradient lattice structures. The method used was uniaxial compression simulations using finite element analysis to identify the translational displacements.

From the simulation results, in comparison to the cubic lattice structure, the octet-truss lattice structure showed a significant difference in mechanical behaviour. In the same design space, the translational displacement for both lattice structures increased as the relative density decreased. Apart from the relative density, the microarchitecture of the lattice structure also influenced the mechanical behaviour of the gradient lattice structure.

Gradient lattice structures are suitable for bone implant applications because of the variation of pore sizes that mimic the natural bone structures. The complex geometry that gradient lattice structures possess can be manufactured using additive manufacturing technology.

The results demonstrated that the cubic gradient lattice structure has the best mechanical behaviour for bone implants with appropriate relative density and pore size.

The quality of lost foam casted engineering components is directly influenced by the characteristics of the respective ceramic shell mold (CSM) and hence casting pattern. In this present work, rapid prototyping (RP) was used to fabricate the lattice structured patterns (LSPs) to reduce the defects and cracks in CSM during the heating stage.

The quality of the LSPs was accessed by measuring the dimensional accuracy. Further, the thermal stress in the CSM during the heating of porosity varied LSPs was analyzed using ANSYS software package 16.0. The Ni-alloy casting was fabricated by using the designed LSP and compared with its respective CAD model to access its quality.

The obtained results revealed that the Wigner–Seitz LSPs retained high accuracy and minimized the stress for defect-free CSM. Also, the thermal stress generated in the CSM depends upon the porosity coefficient of the LSP. Hence the interplay with porosity coefficient of LSPs leads to the formation of defect free CSM and hence high quality casting.

RP was used to develop LSPs and investigated the dependency of unit cell parameters on the accuracy of the final casting.

The manufacturability of extremely fine porous structures in the SLM process has rarely been investigated, leading to unpredicted manufacturing results and preventing steady medical or industrial application. The research objective is to find out the process limitation and key processing parameters for printing fine porous structures so as to give reference for design and manufacturing planning.

In metallic AM processes, the difficulty of geometric modeling and manufacturing of structures with pore sizes less than 350 μm exists. The manufacturability of porous structures in selective laser melting (SLM) has rarely been investigated, leading to unpredicted manufacturing results and preventing steady medical or industrial application. To solve this problem, a comprehensive experimental study was conducted to benchmark the manufacturability of the SLM process for extremely fine porous structures (less than 350 um and near a limitation of 100 um) and propose a manufacturing result evaluation method. Numerous porous structure samples were printed to help collect critical datasets for manufacturability analysis.

The results show that the SLM process can achieve an extreme fine feature with a diameter of 90 μm in stable process control, and the process parameters with their control strategies as well as the printing process planning have an important impact on the printing results. A statistical analysis reveals the implicit complex relations between the porous structure geometries and the SLM process parameter settings.

It is the first time to investigate the manufacturability of extremely fine porous structures of SLM. The method for manufacturability analysis and printing parameter control of fine porous structure are discussed.

The objective of this study is to investigate the feasibility of using selective laser melting (SLM) process to print fine capillary wick porous structures for heat pipe applications and clarify the interrelations between the printing parameters and the structure functional performance to form guidelines for design and printing preparation.

A new toolpath-based construction method is adopted to prepare the printing of capillary wick with fine pores in SLM process. This method uses physical melting toolpath profile with associated printing parameters to directly define slices and assemble them into a printing data model to ensure manufacturability and reduce precision loss of data model transformation in the printing preparation stage. The performance of the sample was characterised by a set of standard experiments and the relationship between the printing parameters and the structure performance is modeled.

The results show that SLM-printed capillary wick porous structures exhibit better performance in terms of pore diameter and related permeability than that of structures formed using traditional sintering methods, generally 15 times greater. The print hatching space and infilling pattern have a critical impact on functional porosity and permeability. An empirical formula was obtained to describe this impact and can serve as a reference for the design and printing of capillary wicks in future applications.

This research proves the feasibility of using SLM process to printing functional capillary wicks in extremely fine pores with improved functional performance. It is the first time to reveal the relations among the pore shapes, printing parameters and functional performance. The research results can be used as a reference for heat pipe design and printing in future industrial applications.

Solid freeform fabrication is particularly suitable for fabricating customized parts, but it has not been used for fabricating deployable structures that can be stored in a compact configuration and deployed quickly and easily in the field. The purpose of this paper is to present a methodology for deploying flexible, freeform structure with lattice skins as the deploying mechanism.

A ground structure‐based topology optimization procedure is utilized, with a penalization scheme that encourages convergence to sets of thick lattice elements that are manufacturable and extremely thin lattice elements that are removed from the final structure.

A deployable wing is designed for a miniature unmanned aerial vehicle. A physical prototype of the optimal configuration is fabricated with selective laser sintering and compared with the virtual prototype. The proposed methodology results in a 78 percent improvement in deviations from the intended surface profile of the deployed part.

The results presented in the paper provide proof‐of‐concept for the use of lattice skins as a deployment mechanism. A topology optimization framework is also provided for designing these lattice skins. Potential applications include portable, camouflaged shelters and deployable aerial vehicles.

This paper aims to examine the static compression characteristics of cell topologies in body-centered cubic with vertical struts (BCCZ) and face-centered cubic with vertical struts (FCCZ) along with novel BCCZZ and FCCZZ lattice structures.

The newly developed structures were obtained by adding extra interior vertical struts into the BCCZ and FCCZ configurations. The samples, composed of the AlSi10Mg alloy, were fabricated using the selective laser melting (SLM) additive manufacturing technique. The specific compressive strength and failure behavior of the manufactured lattice structures were investigated, and comparative analysis among them was done.

The results revealed that the specific strength of BCCZZ and FCCZZ samples with 0.5 mm strut diameter exhibited approximately a 23% and 18% increase, respectively, compared with the BCCZ and FCCZ samples with identical strut diameters. Moreover, finite element analysis was carried out to simulate the compressive response of the lattice structures, which could be used to predict their strength and collapse mode. The findings showed that while the local buckling of lattice cells is the major failure mode, the samples subsequently collapsed along a diagonal shear band.

An original and systematic investigation was conducted to explore the compression properties of newly fabricated lattice structures using SLM. The results revealed that the novel FCCZZ and BCCZZ structures were found to possess significant potential for load-bearing applications.

This paper aims to investigate the feasibility of supportless printing of lattice structures by metal fused filament fabrication (MF³) of Ti-6Al-4V. Additionally, an empirical method was presented for the estimation of extrudate deflection in unsupported regions of lattice cells for different geometric configurations.

Metal-polymer feedstock with a solids-loading of 59 Vol.% compounded and extruded into a filament was used for three-dimensional printing of lattice structures. A unit cell was used as a starting point, which was then extended to multi-stacked lattice structures. Feasible MF³ processing conditions were identified to fabricate defect-free lattice structures. The effects of lattice geometry parameters on part deflection and relative density were investigated at the unit cell level. Computational simulations were used to predict the part quality and results were verified by experimental printing. Finally, using the identified processing and geometry parameters, multi-stacked lattice structures were successfully printed and sintered.

Lattice geometry required considerable changes in MF³ printing parameters as compared to printing bulk parts. Lattice cell dimensions showed a considerable effect on dimensional variations and relative density due to varying aspect ratios. The experimental printing of lattice showed large deflection/sagging in unsupported regions due to gravity, whereas simulation was unable to estimate such deflection. Hence, an analytical model was presented to estimate extrudate deflections and verified with experimental results. Lack of diffusion between beads was observed in the bottom facing surface of unsupported geometry of sintered unit cells as an effect of extrudate sagging in the green part stage. This study proves that MF³ can fabricate fully dense Ti-6Al-4V lattice structures that appear to be a promising candidate for applications where mechanical performance, light-weighting and design customization are required.

Supportless printing of lattice structures having tiny cross-sectional areas and unsupported geometries is highly challenging for an extrusion-based additive manufacturing (AM) process. This study investigated the AM of Ti-6Al-4V supportless lattice structures using the MF³ process for the first time.

Giant orthogonal grid barrel vault is generated by deleting members in the inessential force transfer path of the two-layer lattice barrel vault. Consisting of members in the essential transfer path only, giant orthogonal grid barrel vault is a new type of structure with clear mechanical behavior and efficient material utilization. The paper aims to discuss this issue.

The geometrical configuration of this structure is analyzed, and the geometrical modeling method is proposed. When necessary parameters are determined, such as the structural span, length, vault rise, longitudinal and lateral giant grid number and section height to top chord length ratio of the lattice member, the structure geometrical model can be generated.

Numerical models of giant orthogonal grid barrel vaults with different rise–span ratios are built using the member model that can simulate the pre-buckling and post-buckling behavior. So the possible member buckle-straighten process and the plastic hinge form–disappear process of the structure under strong earthquake can be simulated.

Seismic analysis results indicate that when the structure damages under strong earthquake there are a large number of buckling members and few endpoint plastic hinges in the structure. Dynamic damage of giant orthogonal grid barrel vault under strong earthquake is caused by buckling members that weaken the structural bearing capacity.