The influence of defects on the elastic response of lattice structures resulting from additive manufacturing

2021 ◽  
Vol 199 ◽  
pp. 110716
Author(s):  
Panwei Jiang ◽  
Edward C. De Meter ◽  
Saurabh Basu
Keyword(s):  
Additive Manufacturing ◽  
Elastic Response ◽  
Lattice Structures

Mechanical Response of Different Lattice Structures Fabricated Using the CLIP Technology

2016 ◽  
Author(s):  
Anil Saigal ◽  
John R. Tumbleston ◽  
Hendric Vogel
Keyword(s):  
Additive Manufacturing ◽  
Mechanical Response ◽  
Elastic Response ◽  
Lattice Structures ◽  
Rhombic Dodecahedron ◽  
Structured Materials ◽  
Specific Strength ◽  
Strain Behavior ◽  
End Use ◽  
Continuous Liquid Interface Production

In the rapidly growing field of additive manufacturing (AM), the focus in recent years has shifted from prototyping to manufacturing fully functional, ultralight, ultrastiff end-use parts. This research investigates the mechanical behavior of octahedral, octet, vertex centroid, dode, diamond, rhombi octahedron, rhombic dodecahedron and solid lattice structured polyacrylate fabricated using Continuous Liquid Interface Production (CLIP) technology based on 3D printing and additive manufacturing processes. The compressive stress-strain behavior of the lattice structures observed is typical of cellular structures which include a region of nominally elastic response, yielding, plastic strain hardening to a peak in strength, followed by a drop in flow stress to a plateau region and finally rapid hardening associated with contact of the deformed struts with each other as part of densification. It was found that the elastic modulus and strength of the various lattice structured materials are proportional to each other. In addition, it was found that the octahedral, octet and diamond lattice structures are amongst the most efficient based on the measured specific stiffness and specific strength.

Mechanical Behavior of As-Fabricated and UV-Cured Lattice Structures Printed Using the CLIP Technology

2017 ◽  
Author(s):  
Anil Saigal ◽  
John R. Tumbleston ◽  
Hendric Vogel
Keyword(s):  
Additive Manufacturing ◽  
Mechanical Behavior ◽  
Relative Density ◽  
Uv Curing ◽  
Elastic Response ◽  
Lattice Structures ◽  
Minimum Diameter ◽  
Strain Behavior ◽  
End Use ◽  
Continuous Liquid Interface Production

In the rapidly growing field of additive manufacturing (AM), the focus in recent years has shifted from prototyping to manufacturing fully functional, ultralight, ultrastiff end-use parts. This research investigates the mechanical behavior of octahedral and octet lattice structured polyacrylate fabricated using Continuous Liquid Interface Production (CLIP) technology based on 3D printing and additive manufacturing processes. Five different octahedral structures and seven different octet structures with relative densities ranging from approximately 0.07 to 0.35 were fabricated by changing the strut diameter. The minimum diameter of the strut elements is 0.50 mm and 0.35 mm for the octahedral and octet structures, respectively. The different relative density structures were tested in compression in the as-fabricated state and after they were UV cured. The compressive stress-strain behavior of the lattice structures observed is typical of cellular structures which include a region of nominally elastic response, yielding, and plastic strain hardening to a peak in strength, followed by a drop in flow stress. It was found that the stiffness and strength of octahedral lattice structures is greater than the stiffness and strength of octet lattice structures at all relative densities for both as printed/fabricated and UV cured parts, and the ratio of stiffness and strength of UV cured parts to as fabricated parts decreases as the relative density increases. However, the ratio of stiffness and strength of UV cured parts to as fabricated parts for octet lattice structures in general is greater than that for octahedral structures. This can be attributed to the relative diameter of the struts and the depth of UV curing.

Design for laser powder bed additive manufacturing of AlSi12 periodic mesoscale lattice structures

2021 ◽  
Vol 113 (11-12) ◽  
pp. 3599-3612
Author(s):  
Chen Zhang ◽  
Abhishek Banerjee ◽  
Alison Hoe ◽  
Achutha Tamraparni ◽  
Jonathan R. Felts ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Lattice Structures ◽  
Powder Bed

scholarly journals Macro-, meso- and microstructural characterization of metallic lattice structures manufactured by additive manufacturing assisted investment casting

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
V. H. Carneiro ◽  
S. D. Rawson ◽  
H . Puga ◽  
P. J. Withers
Keyword(s):  
Additive Manufacturing ◽  
Investment Casting ◽  
A356 Alloy ◽  
Microstructural Characterization ◽  
Lattice Structures ◽  
Secondary Phases ◽  
Micro Computed Tomography ◽  
Fused Filament Fabrication ◽  
Promising Alternative ◽  
Heterogeneous Microstructures

AbstractCellular materials are recognized for their high specific mechanical properties, making them desirable in ultra-lightweight applications. Periodic lattices have tunable properties and may be manufactured by metallic additive manufacturing (AM) techniques. However, AM can lead to issues with un-melted powder, macro/micro porosity, dimensional control and heterogeneous microstructures. This study overcomes these problems through a novel technique, combining additive manufacturing and investment casting to produce detailed investment cast lattice structures. Fused filament fabrication is used to fabricate a pattern used as the mold for the investment casting of aluminium A356 alloy into high-conformity thin-ribbed (~ 0.6 mm thickness) scaffolds. X-ray micro-computed tomography (CT) is used to characterize macro- and meso-scale defects. Optical and scanning electron (SEM) microscopies are used to characterize the microstructure of the cast structures. Slight dimensional (macroscale) variations originate from the 3D printing of the pattern. At the mesoscale, the casting process introduces very fine (~ 3 µm) porosity, along with small numbers of (~ 25 µm) gas entrapment defects in the horizontal struts. At a microstructural level, both the (~ 70 μm) globular/dendritic grains and secondary phases show no significant variations across the lattices. This method is a promising alternative means for producing highly detailed non-stochastic metallic cellular lattices and offers scope for further improvement through refinement of filament fabrication.

scholarly journals FEASIBILITY STUDY OF MICRO-LATTICE STRUCTURES BY MULTIPHOTON LITHOGRAPHY

2019 ◽  
Vol 25 ◽  
pp. 83-88
Author(s):  
Markus Wimmer ◽  
Zoltan Major
Keyword(s):  
Additive Manufacturing ◽  
Laser Beam ◽  
Constant Density ◽  
Lattice Structures ◽  
Post Processing ◽  
Constant Frequency ◽  
Layer Height ◽  
Lithography Process ◽  
Multiphoton Lithography ◽  
Laser Firing

The paper describes the possibilities of additive manufacturing with multiphoton lithography. The basis of this technology is that a laser beam (with a certain wavelength) is fired into the mixture of a monomer and a photo-initiator. When the energy of the laser is high enough, the latter acts as a catalyser for the polymerization of the monomer compound. This study focuses on the influences of certain parameters of the multiphoton lithography process. One of the important aspects is the choice of the solvent for the post processing. In sequence to the solvent problem, the influence of the layer height is examined. Furthermore the limits and possibilities of the setup in use are investigated. As an example the differences in fabrication with the laser firing with "constant frequency" and "constant density" were subject of this investigation. The second goal of the study was to compare three different structures consisting of periodically repeating elements, scaled in size and number of elements per side.

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