Freedom of design, mass customisation, waste minimisation and the ability to manufacture complex structures, as well as fast prototyping, are the main benefits of additive manufacturing (AM) or 3D printing. A comprehensive review of the main 3D printing methods, materials and their development in trending applications was carried out. In particular, the revolutionary applications of AM in biomedical, aerospace, buildings and protective structures were discussed. The current state of materials development, including metal alloys, polymer composites, ceramics and concrete, was presented. In addition, this paper discussed the main processing challenges with void formation, anisotropic behaviour, the limitation of computer design and layer-by-layer appearance. Overall, this paper gives an overview of 3D printing, including a survey on its benefits and drawbacks as a benchmark for future research and development.

Additive manufacturing (3D printing): A review of materials, methods, applications and challenges

The present invention relates to graphene-based foam, the graphene-based foam having a structure defined by a three-dimensional network of interconnected and ordered open cells, the open cells being defined by cell walls, the cell walls (i) being formed of graphene sheets, partially reduced graphene oxide sheets, reduced graphene oxide sheets, or a combination thereof, and (ii) having a thickness defined by the thickness of a plurality of graphene sheets, partially reduced graphene oxide sheets, reduced graphene oxide sheets, or a combination thereof.

https://science.sciencemag.org/content/sci/320/5880/1170.full.pdf

Graphene-based materials

Classifications, applications, and design challenges of drones: A review

Additive manufacturing enables fabrication of materials with intricate cellular architecture, whereby progress in 3D printing techniques is increasing the possible configurations of voids and solids ad infinitum. Examples are microlattices with graded porosity and truss structures optimized for specific loading conditions. The cellular architecture determines the mechanical properties and density of these materials and can influence a wide range of other properties, e.g., acoustic, thermal, and biological properties. By combining optimized cellular architectures with high-performance metals and ceramics, several lightweight materials that exhibit strength and stiffness previously unachievable at low densities were recently demonstrated. This review introduces the field of architected materials; summarizes the most common fabrication methods, with an emphasis on additive manufacturing; and discusses recent progress in the development of architected materials. The review also discusses important application...

Architected Cellular Materials

Mechanical Metamaterials and Their Engineering Applications

Multifunctional heat exchangers derived from three-dimensional micro-lattice structures

The fluid dynamics of flow through microscale lattice structures is characterized for different unit cell sizes, flow angles, and flow rates. The structures consist of an octahedral-type periodic unit cell, which is formed from an interconnected pattern of self-propagating photopolymer waveguides. The periodic unit cell of each sample has a node-to-node spacing between 800 and 2400 μm and a truss member diameter between 148 and 277 μm. Water is directed through the microscale lattice structures, and the resulting pressure drop is investigated for two different flow angles and superficial flow rates between 0.5 and 4.8 L/min. Finite element analysis is used to determine pressure drop in the laminar flow regime. The results are used to develop a correlation describing friction factor as a function of flow direction, geometric characteristics, and Reynolds number. This work enables control of the fluid dynamics in microarchitected multifunctional truss materials through design and superficial flow angle. © 2010 American Institute of Chemical Engineers AIChE J, 2011

Fluid dynamics of flow through microscale lattice structures formed from self‐propagating photopolymer waveguides

Fluid dynamics and heat transfer of flow through periodic open-cellular microlattice structures are characterized for varying superficial flow orientations and flow rates to investigate heat transfer and pressure loss anisotropy. For given Reynolds number, friction factor is lowest when flow is aligned with the largest straight-through passages in the microlattice. A maximum friction factor, over twice the optimally aligned friction factor, exists for flow orientations between π/8 and π/4 rad off the optimal alignment, with little variation in friction factor for π/8 and π/4 rad. Heat transfer is maximized at π/4 rad off axis from the largest straight-through passages; however, less angular variation occurs in Nusselt number than in friction factor. Empirical correlations involving superellipses yield analytical equations describing Nusselt number dependence on flow angle and Reynolds number. This work enables selection of optimal flow orientations and optimal cellular architecture in convective heat transfer implementations of microlattice materials for lightweight and multifunctional applications. © 2012 American Institute of Chemical Engineers AIChE J, 59: 622–629, 2013

Anisotropic convective heat transfer in microlattice materials

In this paper, we describe a rapid method for fabricating a low density polymer microlattice with structural organization on two length scales. The topology of this hierarchical cellular structure is achieved through the in situ formation of a microlattice with small-scale lattice members (≈100 µm diameter) within a microlattice with approximately 12 times larger feature sizes. Compression experiments suggest that an increase in the specific plateau stress is realized by the introduction of hierarchy.

Hierarchical Polymer Microlattice Structures

A three-dimensional micro-truss structure includes: a plurality of first struts extending along a first direction; a plurality of second struts extending along a second direction; a plurality of third struts extending along a third direction; and a plurality of fourth struts extending along a fourth direction, wherein the first, second, third, and fourth struts interpenetrate one another at a plurality of nodes and wherein at least one of the first, second, and third directions extends at a non-perpendicular angle with respect to a plane, the plane being substantially perpendicular to the fourth direction.

Joanna A. Kolodziejska

Papers

Multifunctional heat exchangers derived from three-dimensional micro-lattice structures

Fluid dynamics of flow through microscale lattice structures formed from self‐propagating photopolymer waveguides

Anisotropic convective heat transfer in microlattice materials

Hierarchical Polymer Microlattice Structures

Process of making a three-dimentional micro-truss structure