3D Printing of Strong Lightweight Cellular Structures Using Polysaccharide-Based Composite Foams

2018 ◽  
Vol 6 (12) ◽  
pp. 17160-17167 ◽  
Author(s):  
Hugo P. Voisin ◽  
Korneliya Gordeyeva ◽  
Gilberto Siqueira ◽  
Michael K. Hausmann ◽  
André R. Studart ◽  
...  
2020 ◽  
Vol 35 ◽  
pp. 101348
Author(s):  
Yu Liu ◽  
Zhangwei Chen ◽  
Junjie Li ◽  
Baoping Gong ◽  
Long Wang ◽  
...  

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 249 ◽  
Author(s):  
Long Wang ◽  
Kiyomi Okada ◽  
Yuta Hikima ◽  
Masahiro Ohshima ◽  
Takafumi Sekiguchi ◽  
...  

Herein, lightweight nanocomposite foams with expansion ratios ranging from 2–10-fold were fabricated using an isotactic polypropylene (iPP) matrix and cellulose nanofiber (CNF) as the reinforcing agent via core-back foam injection molding (FIM). Both the native and modified CNFs, including the different degrees of substitution (DS) of 0.2 and 0.4, were melt-prepared and used for producing the polypropylene (PP)/CNF composites. Foaming results revealed that the addition of CNF greatly improved the foamability of PP, reaching 2–3 orders of magnitude increases in cell density, in comparison to those of the neat iPP foams. Moreover, tensile test results showed that the incorporation of CNF increased the tensile modulus and yield stress of both solid and 2-fold foamed PP, and a greater reinforcing effect was achieved in composites containing modified CNF. In the compression test, PP/CNF composite foams prepared with a DS of 0.4 exhibited dramatic improvements in mechanical performance for 10-fold foams, in comparison to iPP, with increases in the elastic modulus and collapse stress of PP foams of 486% and 468%, respectively. These results demonstrate that CNF is extraordinarily helpful in enhancing the foamability of PP and reinforcing PP foams, which has importance for the development of lightweight polymer composite foams containing a natural nanofiber.


2021 ◽  
Vol XXIV (1) ◽  
pp. 8-16
Author(s):  
VOICU Andrei - Daniel

The article makes a brief presentation of the latest 3D printing methods that are used for manufacturing aerospace lattice structures. Most 3D printing technologies are not fully deployed on the industrial scale of aerospace sector, but are rather used for rapid prototyping of components. One of the main potential applications is for them to offer a rapid solution for remote operations, where it is difficult to supply parts. Additive manufactured lattice structures are cellular structures based on biomimicry (inspired from nature lattice structures such as bones, metal crystallography, etc.), that possess many superior properties compared to solid materials and are ideal for fabricating aerospace structures mainly due to the mass reduction they introduce and the high strength-to-weight ratio. Their mechanical properties are defined by the infill percentage, the geometry of the cell structure and the material used in the manufacturing process.


Author(s):  
Ye Kang ◽  
Kwangwon Kim ◽  
Jaehyung Ju

Cellular materials have two important properties: structures and mechanisms. This property enables one to design structures with proper stiffness and flexibility. Recent advance in 3D printing technologies enable engineers to manufacture complex cellular structures. In addition, use of smart materials, e.g., shape memory polymers (SMPs), for 3D printing enables us to construct mesostructures actively responsive to environmental stimuli with a programmable function, which may be termed ‘4D Printing’ referring to additional dimension on time-dependent shape change after 3D printing. The objective of this study is to design and synthesize active reconfigurable cellular materials, which enables the advance of technology on intelligent reconfigurable cellular structures with 4D printing. A two-layer hinge of a CPS functions through a programmed thermal expansion mismatch between two layers and shape memory effect of an SMP. Starting with thermo-mechanical constitutive modeling of a compliant porous hinge consisting of laminated elastomer composites, macroscopic behaviors of a reconfigurable compliant porous structure (CPS) will be constructed using the strain energy method. A finite element (FE) based simulation equipped with a user subroutine will be implemented with ABAQUS/Standard to simulate time-dependent thermo mechanical behaviors of a CPS. The designed CPS with polymers shows an extremely high negative Poisson’s ratio (∼ −120) and negative thermal expansion coefficient (−2,530 × 10−6/C). When programmed with an appropriate thermo-mechanical procedure, the hinge of the CPS bends either in positive and negative sign, which enables to tailor the CPS into desired intermediate and final configurations, ending up with achieving a reconfigurable CPS. This paper demonstrates that actively reconfigurable compliant cellular materials (CCMs) with CPSes can be used for next-generation materials design in terms of tailoring mechanical properties such as modulus, strength, yield strain, Poisson’s ratios and thermal expansion coefficient together with programmable characteristics.


2021 ◽  
Vol 7 (38) ◽  
Author(s):  
Seok Kim ◽  
Jordan J. Handler ◽  
Young Tae Cho ◽  
George Barbastathis ◽  
Nicholas X. Fang

Mechanik ◽  
2018 ◽  
Vol 91 (3) ◽  
pp. 250-252 ◽  
Author(s):  
Piotr Dziewit ◽  
Jacek Janiszewski

Presented are selected experimental results concerning the analysis of the deformation process of regular cellular structures manufactured using 3D printing under quasi-static loading conditions. The various structural topologies were designed and manufactured using the FDM (fused deposition modelling) and then tested in a uniaxial compression test. The starting point for the development of individual variants of structures was the honeycomb topology. In order to analyse the influence of the structure material on the deformation process, the samples were made from three commercially available materials: PC-10, ABSplus and Nylon12. Based on the results, the influence of the shape of the single cell and the type of material used on the deformation of the structure as well as the value of the plastic deformation energy were assessed.


2015 ◽  
Vol 17 (7) ◽  
pp. 923-932 ◽  
Author(s):  
Dean Snelling ◽  
Qian Li ◽  
Nicolas Meisel ◽  
Christopher B. Williams ◽  
Romesh C. Batra ◽  
...  

2020 ◽  
Vol 2 (4) ◽  
Author(s):  
Riccardo Balzarotti ◽  
Alessandra Bisaccia ◽  
Maria Celeste Tripi ◽  
Matteo Ambrosetti ◽  
Gianpiero Groppi ◽  
...  

Author(s):  
F.J. Sjostrand

In the 1940's and 1950's electron microscopy conferences were attended with everybody interested in learning about the latest technical developments for one very obvious reason. There was the electron microscope with its outstanding performance but nobody could make very much use of it because we were lacking proper techniques to prepare biological specimens. The development of the thin sectioning technique with its perfectioning in 1952 changed the situation and systematic analysis of the structure of cells could now be pursued. Since then electron microscopists have in general become satisfied with the level of resolution at which cellular structures can be analyzed when applying this technique. There has been little interest in trying to push the limit of resolution closer to that determined by the resolving power of the electron microscope.


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