Mechanical Behavior of Octahedral and Octet Structures Produced From CLIP Technology

2018 ◽  
Author(s):  
Gian J. Calise ◽  
Anil Saigal
Keyword(s):  
Mechanical Properties ◽  
Large Scale ◽  
Mechanical Response ◽  
Peak Stress ◽  
Lattice Structures ◽  
Mechanical Metamaterials ◽  
Material Component ◽  
Wide Range ◽  
Athletic Shoes ◽  
Continuous Liquid Interface Production

This research concerns the production of mechanical metamaterials by a new means of additive manufacturing (AM). Mechanical metamaterials are man-made materials in which the mechanical properties are defined mainly by their structures rather than the properties of each material component. They are typically cellular lattice structures consisting of various arrangements of interconnected webs and struts. These metamaterials have a wide range of applications, but due to a recent breakthrough technology in the field of AM developed by Carbon, called Continuous Liquid Interface Production (CLIP), they can now be produced with ease at substantially higher speeds on a large scale. Using the CLIP process, Adidas is now utilizing these metamaterials in the midsoles of their new athletic shoes. More information about the mechanical response of parts produced by CLIP was needed to assess their relevance in this application. The goal of this research was to quantitatively determine the isotropy of octahedral and octet lattice structures produced from CLIP technology. Carbon claims that CLIP technology, unlike most other AM processes, produces parts that are isotropic. This means parts will have the same mechanical properties regardless of the direction of applied load. This claim has yet to be proven on lattice structures like the octahedral and octet structures. Those particular lattice structures are popular in the field of mechanical metamaterials because they are more structurally efficient than foams that are made of the same material with similar densities. The degree of isotropy of samples was measured by comparing values of various mechanical properties. These properties include Young’s modulus, a common measure of elasticity, and peak stress, a common measure of strength. Results indicated relatively isotropic behavior because mechanical properties varied based on the axis of compression by 6.5%, on average. The physical responses and failure mechanisms were also consistent.

scholarly journals Decoupling local mechanics from large-scale structure in modular metamaterials

2017 ◽  
Vol 114 (14) ◽  
pp. 3590-3595 ◽  
Author(s):  
Nan Yang ◽  
Jesse L. Silverberg
Keyword(s):  
Mechanical Properties ◽  
Large Scale ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Design Parameters ◽  
Mechanical Function ◽  
Large Scale Structures ◽  
Mechanical Metamaterials ◽  
Wide Range ◽  
Scale Structures

A defining feature of mechanical metamaterials is that their properties are determined by the organization of internal structure instead of the raw fabrication materials. This shift of attention to engineering internal degrees of freedom has coaxed relatively simple materials into exhibiting a wide range of remarkable mechanical properties. For practical applications to be realized, however, this nascent understanding of metamaterial design must be translated into a capacity for engineering large-scale structures with prescribed mechanical functionality. Thus, the challenge is to systematically map desired functionality of large-scale structures backward into a design scheme while using finite parameter domains. Such “inverse design” is often complicated by the deep coupling between large-scale structure and local mechanical function, which limits the available design space. Here, we introduce a design strategy for constructing 1D, 2D, and 3D mechanical metamaterials inspired by modular origami and kirigami. Our approach is to assemble a number of modules into a voxelized large-scale structure, where the module’s design has a greater number of mechanical design parameters than the number of constraints imposed by bulk assembly. This inequality allows each voxel in the bulk structure to be uniquely assigned mechanical properties independent from its ability to connect and deform with its neighbors. In studying specific examples of large-scale metamaterial structures we show that a decoupling of global structure from local mechanical function allows for a variety of mechanically and topologically complex designs.

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.

Combining ExoMars’ Ma_MISS and Drill data

2020 ◽  
Author(s):  
Alessandro Frigeri ◽  
Maria Cristina De Sanctis ◽  
Francesca Altieri ◽  
Simone De Angelis ◽  
Marco Ferrari ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Water Content ◽  
Large Scale ◽  
Mechanical Response ◽  
European Space Agency ◽  
Volcanic Rocks ◽  
Space Agency ◽  
Geophysical Imaging

<p>The ExoMars Rover and Surface Platform planned for launch in 2022 is a large international cooperation between the European Space Agency and Roscosmos with a scientific contribution from NASA.  Thales Alenia Space is the ExoMars mission industrial prime contractor. </p> <p>Besides sensors and instruments characterizing the surface at large scale, the ExoMars’ rover Rosalind Franklin payload features some experiments devoted specifically to the characterization of the first few meters of the Martian subsurface. These experiments are particularly critical for the main ExoMars objective of detecting traces of present or past life forms on Mars, which may have been preserved within the shallow Martian underground [1].</p> <p>Rosalind Franklin will be able to perform both non-invasive geophysical imaging of the underground [2] and subsurface <em>in situ</em> measurements thanks to the Drill unit installed on the rover. The Drill has been developed by Leonardo and its purposes are 1) to collect core samples to be analyzed in the Analytical Laboratory Drawer (ALD) onboard the Rover and 2) to drive the miniaturized spectrometer Ma_MISS within the borehole.   </p> <p>Ma_MISS (Mars Multispectral Imager for Subsurface Studies, [3]) will collect mineralogic measurements from the rocks exposed into the borehole created by the Drill with a spatial resolution of 120 μm down to 2 meters into the Martian subsurface.</p> <p>Rocks are composed of grains of minerals, and their reaction to an applied stress is related to the mechanical behavior of the minerals that compose the rock itself. The mechanical properties of a mineral depend mainly on the strength of the chemical bonds, the orientation of crystals, and the number of impurities in the crystal lattice.</p> <p>In this context, the integration of Ma_MISS measurements and drill telemetry are of great importance.  The mechanical properties of rocks coupled with their mineralogic composition provide a rich source of information to characterize the nature of rocks being explored by ExoMars rover’s drilling activity.</p> <p>Within our study, we are starting to collect telemetry recorded during the Drill unit tests on several samples ranging from sedimentary to volcanic rocks with varying degrees of weathering and water content.  In this first phase of the study, we focused our attention on the variation of torque and penetration speed between different samples, which have been found to be indicative of a particular type of rock or group of rocks and their water content.  </p> <p>We are planning to analyze the same rocks with the Ma_MISS breadboard creating the link between the mineralogy and the mechanical response of the Drill.      </p> <p>This will put the base for a more comprehensive and rich characterization of the <em>in situ</em> subsurface observation by Rosalind Franklin planned at Oxia Planum, Mars in 2023. </p> <p> </p> <p><strong>Acknowledgments: </strong>We thank the European Space Agency (ESA) for developing the ExoMars Project, ROSCOSMOS and Thales Alenia Space for rover development, and Italian Space Agency (ASI) for funding the Ma_MISS experiment (ASI-INAF contract n.2017-48-H.0 for ExoMars MA_MISS phase E/science).</p> <p> </p> <p><strong>References</strong></p> <p>[1] Vago et al., 2017. Astrobiology, 17 6-7. [2] Ciarletti et al., 2017. Astrobiology, 17 6-7. [3] De Sanctis et al., 2017. Astrobiology, 17 6-7.</p>

Progress in the Development of a Mechanical Properties Microprobe

MRS Bulletin ◽  
1986 ◽  
Vol 11 (5) ◽  
pp. 15-21 ◽  
Author(s):  
W. C. Oliver
Keyword(s):  
Mechanical Properties ◽  
Mechanical Response ◽  
Quantitative Information ◽  
General Term ◽  
Strength Properties ◽  
Physical Measurements ◽  
Wide Range ◽  
The Matrix ◽  
Recent Developments ◽  
Skilled Practitioner

A mechanical properties microprobe is an exciting concept. A system with the ability to evaluate the mechanical response of a sample with submicron spacial resolution would have an extremely wide range of applications. Recent developments in hardware and understanding have placed this goal within our grasp.In 1971, J.J.Gilman wrote the following in his article, “Hardness—A Strength Microprobe”:“Hardness measurements are at once among the most maligned and the most magnificent of physical measurements. Maligned because they are often misinterpreted by the uninitiated, and magnificent because they are so efficient in generating information for the skilled practitioner. They can quickly yield quantitative information about the elastic, anelastic, plastic, viscous, and fracture properties of a great variety of both isotropic and anisotropic solids. The tools that are used are simple and the sample sizes that are needed are typically small, sometimes submicroscopic. This makes it unnecessary to have large specimens in order to measure strength properties and makes it possible to measure the properties of various microscopic particles within the matrix phase of a polyphase metal, mineral, or ceramic material. This is why hardness may be considered to be a strength microprobe.”These statements are worth repeating for two reasons. First, they point out the largely untapped potential for microin-dentation tests to improve our understanding of the mechanical properties of materials. Second, it is the first mention of hardness tests in the context of a strength microprobe. In this article the more general term of microindentation tests will be used, since hardness is only one of many properties that can be measured with such tests. In addition, the term mechanical properties microprobe (MPM) will be used rather than strength microprobe-again, to note the wide variety of properties that can be measured.

Preparation of Metal-Gr Composite Coatings via Electro-Plating for High Performances: A Review

MRS Advances ◽  
2019 ◽  
Vol 4 (35) ◽  
pp. 1913-1928
Author(s):  
Sishi Li ◽  
Yanpeng Yang ◽  
Gongsheng Song ◽  
Qiang Fu ◽  
Chunxu Pan
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Large Scale ◽  
Low Cost ◽  
Composite Coatings ◽  
Scale Production ◽  
Electro Deposition ◽  
Wide Range ◽  
Set Up ◽  
Wear And Corrosion Resistance

ABSTRACTDeveloping metal-based composite coatings with improved mechanical properties and good corrosion resistance has been an attractive research topic in recent years. Graphene (Gr), as a new type of two-dimensional (2D) carbon nanomaterial with excellent physical, chemical and mechanical properties, can be used as a reinforcement to improve hardness, tensile strength, wear and corrosion resistance of metal-based composites. There have been substantial efforts focused on the fabrication of metal-Gr composite coatings via various approaches. Electro-deposition is an effective electrochemical method with wide range of advantages, such as a fast deposition rate, simple set-up with large scale production and relatively low cost. This overview covers the previous research and development studies on metal-Gr composite coatings using electro-deposition method and the resulting properties. In addition, recent work in this area which provides a developed process with industrial production perspective, is discussed.

scholarly journals Improvement of Mechanical Properties of Plasma Sprayed Al2O3-ZrO2-SiO2 Amorphous Coatings by Surface Crystallization

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3232 ◽  
Author(s):  
Jan Medricky ◽  
Frantisek Lukac ◽  
Stefan Csaki ◽  
Sarka Houdkova ◽  
Maria Barbosa ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Wear Resistance ◽  
Large Scale ◽  
Mechanical Response ◽  
High Energy ◽  
Hardness Profile ◽  
Treatment Conditions ◽  
Content Ratio ◽  
Plasma Sprayed

Ceramic Al2O3-ZrO2-SiO2 coatings with near eutectic composition were plasma sprayed using hybrid water stabilized plasma torch (WSP-H). The as-sprayed coatings possessed fully amorphous microstructure which can be transformed to nanocrystalline by further heat treatment. The amorphous/crystalline content ratio and the crystallite sizes can be controlled by a specific choice of heat treatment conditions, subsequently leading to significant changes in the microstructure and mechanical properties of the coatings, such as hardness or wear resistance. In this study, two advanced methods of surface heat treatment were realized by plasma jet or by high energy laser heating. As opposed to the traditional furnace treatments, inducing homogeneous changes throughout the material, both approaches lead to a formation of gradient microstructure within the coatings; from dominantly amorphous at the substrate–coating interface vicinity to fully nanocrystalline near its surface. The processes can also be applied for large-scale applications and do not induce detrimental changes to the underlying substrate materials. The respective mechanical response was evaluated by measuring coating hardness profile and wear resistance. For some of the heat treatment conditions, an increase in the coating microhardness by factor up to 1.8 was observed, as well as improvement of wear resistance behaviour up to 6.5 times. The phase composition changes were analysed by X-ray diffraction and the microstructure was investigated by scanning electron microscopy.

Intraoperative Strain Elastosonography in Brain Tumor Surgery

2018 ◽  
Vol 17 (2) ◽  
pp. 227-236 ◽  
Author(s):  
Francesco Prada ◽  
Massimiliano Del Bene ◽  
Angela Rampini ◽  
Luca Mattei ◽  
Cecilia Casali ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Brain Tumor ◽  
Large Scale ◽  
Imaging Technique ◽  
Low Grade ◽  
Tumor Surgery ◽  
Brain Tumor Surgery ◽  
Mode Iii ◽  
Wide Range ◽  
The Brain

Abstract BACKGROUND Sonoelastography is an ultrasound imaging technique able to assess mechanical properties of tissues. Strain elastography (SE) is a qualitative sonoelastographic modality with a wide range of clinical applications, but its use in brain tumor surgery has been so far very limited. OBJECTIVE To describe the first large-scale implementation of SE in oncological neurosurgery for lesions discrimination and characterization. METHODS We analyzed retrospective data from 64 patients aiming at (i) evaluating the stiffness of the lesion and of the surrounding brain, (ii) assessing the correspondence between B-mode and SE, and (iii) performing subgroup analysis for gliomas characterization RESULTS (i) In all cases, we visualized the lesion and the surrounding brain with SE, permitting a qualitative stiffness assessment. (ii) In 90% of cases, lesion representations in B-mode and SE were superimposable with identical morphology and margins. In 64% of cases, lesion margins were sharper in SE than in B-mode. (iii) In 76% of cases, glioma margins were sharper in SE than in B-mode. Lesions morphology/dimensions in SE and in B-mode were superimposable in 89%. Low-grade (LGG) and high-grade (HGG) gliomas were significantly different in terms of stiffness and stiffness contrast between tumors and brain, LGG appearing stiffer while HGG softer than brain (all P < ·001). A threshold of 2.5 SE score had 85.7% sensitivity and 94.7% specificity in differentiating LGG from HGG. CONCLUSION SE allows to understand mechanical properties of the brain and lesions in examination and permits a better discrimination between different tissues compared to B-mode. Additionally, SE can differentiate between LGG and HGG.

The Effect of Surface Depressions on Conformal and Nonconformal Contact Pressure Distributions

1986 ◽  
Vol 53 (4) ◽  
pp. 779-784 ◽  
Author(s):  
H. H. Chen ◽  
K. M. Marshek
Keyword(s):  
Stress Concentration ◽  
Large Scale ◽  
Large Deviation ◽  
Peak Stress ◽  
Contact Problems ◽  
Elastic Half Space ◽  
Design Tool ◽  
Pressure Distributions ◽  
Wide Range ◽  
Multiply Connected Regions

This paper presents a numerical method for analyzing the stress concentration around one or several shallow longitudinal surface depressions. The modified iterative method and modified influence function are used in conjunction with an automatic mesh generation technique to avoid solving the ill-condition of the large scale linear system and therefore a wide range of contact problems having multiply-connected regions can be solved. The effect of the blending radius and the pit size on the stress concentration for a pitted copper cylinder contacting an elastic half space are examined. The conformal pressure distributions for a smooth steel journal contacting a self-lubricated bearing with various radial clearances and material properties are also determined. The numerical results show that the smaller the blend radii, the higher the stress concentration for a given pit size. A large deviation from the Hertzian solution is observed for a surface with large pits because of the loss of pressure supporting area. The results of the analysis provides a design tool for predicting the magnitude and location of the peak stress for the rolling and sliding contact elements.

scholarly journals Soft-Tissue-Mimicking Using Hydrogels for the Development of Phantoms

Gels ◽  
2022 ◽  
Vol 8 (1) ◽  
pp. 40
Author(s):  
Aitor Tejo-Otero ◽  
Felip Fenollosa-Artés ◽  
Isabel Achaerandio ◽  
Sergi Rey-Vinolas ◽  
Irene Buj-Corral ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Soft Tissues ◽  
Mechanical Response ◽  
Viscoelastic Behavior ◽  
Linear Elastic ◽  
Lack Of Information ◽  
Wide Range ◽  
Significant Difference ◽  
Promising Solution ◽  
Living Tissues

With the currently available materials and technologies it is difficult to mimic the mechanical properties of soft living tissues. Additionally, another significant problem is the lack of information about the mechanical properties of these tissues. Alternatively, the use of phantoms offers a promising solution to simulate biological bodies. For this reason, to advance in the state-of-the-art a wide range of organs (e.g., liver, heart, kidney as well as brain) and hydrogels (e.g., agarose, polyvinyl alcohol –PVA–, Phytagel –PHY– and methacrylate gelatine –GelMA–) were tested regarding their mechanical properties. For that, viscoelastic behavior, hardness, as well as a non-linear elastic mechanical response were measured. It was seen that there was a significant difference among the results for the different mentioned soft tissues. Some of them appear to be more elastic than viscous as well as being softer or harder. With all this information in mind, a correlation between the mechanical properties of the organs and the different materials was performed. The next conclusions were drawn: (1) to mimic the liver, the best material is 1% wt agarose; (2) to mimic the heart, the best material is 2% wt agarose; (3) to mimic the kidney, the best material is 4% wt GelMA; and (4) to mimic the brain, the best materials are 4% wt GelMA and 1% wt agarose. Neither PVA nor PHY was selected to mimic any of the studied tissues.

scholarly journals Folding of Tubular Waterbomb

Research ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Jiayao Ma ◽  
Huijuan Feng ◽  
Yan Chen ◽  
Degao Hou ◽  
Zhong You
Keyword(s):  
Mechanical Properties ◽  
Fine Tuning ◽  
Design Approach ◽  
Structural Deformation ◽  
Analysis And Design ◽  
The Road ◽  
Mechanical Metamaterials ◽  
Constituent Material ◽  
Wide Range ◽  
First Time

Origami has recently emerged as a promising building block of mechanical metamaterials because it offers a purely geometric design approach independent of scale and constituent material. The folding mechanics of origami-inspired metamaterials, i.e., whether the deformation involves only rotation of crease lines (rigid origami) or both crease rotation and facet distortion (nonrigid origami), is critical for fine-tuning their mechanical properties yet very difficult to determine for origami patterns with complex behaviors. Here, we characterize the folding of tubular waterbomb using a combined kinematic and structural analysis. We for the first time uncover that a waterbomb tube can undergo a mixed mode involving both rigid origami motion and nonrigid structural deformation, and the transition between them can lead to a substantial change in the stiffness. Furthermore, we derive theoretically the range of geometric parameters for the transition to occur, which paves the road to program the mechanical properties of the waterbomb pattern. We expect that such analysis and design approach will be applicable to more general origami patterns to create innovative programmable metamaterials, serving for a wide range of applications including aerospace systems, soft robotics, morphing structures, and medical devices.

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