scholarly journals Structure-Enhanced Mechanically Robust Graphite Foam with Ultrahigh MnO2 Loading for Supercapacitors

Research ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Qinghe Cao ◽  
Junjie Du ◽  
Xiaowan Tang ◽  
Xi Xu ◽  
Longsheng Huang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electrochemical Performance ◽  
Porous Structure ◽  
Flexible Electronics ◽  
Functional Materials ◽  
High Mass ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Digital Light Processing ◽  
Graphite Foam

With the fast bloom of flexible electronics and green vehicles, it is vitally important to rationally design and facilely construct customized functional materials with excellent mechanical properties as well as high electrochemical performance. Herein, by utilizing two modern industrial techniques, digital light processing (DLP) and chemical vapor deposition (CVD), a unique 3D hollow graphite foam (HGF) is demonstrated, which shows a periodic porous structure and robust mechanical properties. Finite element analysis (FEA) results confirm that the properly designed gyroidal porous structure provides a uniform stress area and mitigates potential structural failure caused by stress concentrations. A typical HGF can show a high Young’s modulus of 3.18 MPa at a low density of 48.2 mg cm-3. The porous HGF is further covered by active MnO2 material with a high mass loading of 28.2 mg cm-2 (141 mg cm-3), and the MnO2/HGF electrode still achieves a satisfactory specific capacitance of 260 F g-1, corresponding to a high areal capacitance of 7.35 F cm-2 and a high volumetric capacitance of 36.75 F cm-3. Furthermore, the assembled quasi-solid-state asymmetric supercapacitor also shows remarkable mechanical properties as well as electrochemical performance.

scholarly journals IMCs Microstructure Evolution Dependence of Mechanical Properties for Ni/Sn/Ni Micro Solder-Joints

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 252 ◽  
Author(s):  
Ning Ren ◽  
Heng Fang ◽  
Dong Wang ◽  
Chenyi Hou ◽  
Yatao Zhao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Brittle Fracture ◽  
Ductile Fracture ◽  
Solder Joints ◽  
Volume Fraction ◽  
Tensile Tests ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Scale Down ◽  
Long Rod

The current miniaturization trend of microelectronic devices drives the size of solder joints to continually scale down. The miniaturized joints considerably increase intermetallic compounds (IMCs) volume fraction to trigger mechanical reliability issues. This study investigated precise relationships between varying IMC volumes and mechanical properties of Ni/Sn(20μm)/Ni micro-joints. A designed method that followed the IMC volume as the only variable was used to prepare micro-joint samples with different IMC volumes. The continuously thickened Ni3Sn4 IMCs exhibited a noticeable morphology evolution from rod-like to chunky shape. The subsequent tensile tests showed unexpected tensile strength responses as increasing Ni3Sn4 volume, which was strongly associated with the Ni3Sn4 morphological evolutions. Fractographic analysis displayed that the ductile fracture dominates the 20%–40% IMC micro-joints, whereas the brittle fracture governs the 40%–80% IMC micro-joints. For the ductile fracture-dominated joints, an abnormal reduction in strength occurred as increasing IMCs volume from 20% to 40%. This is primarily due to severe stress concentrations caused by the transformed long rod-typed morphology of the Ni3Sn4. For the brittle fracture-dominated joints, the strength appeared a monotonous increase as the Ni3Sn4 volume increased. This may be attributed to the increased crack resistance resulting from continuous coarsening of the chunky Ni3Sn4 without any voids. Moreover, the finite element analysis was provided to further understand the joint failure mechanisms.

Finite-Element Analysis and Optimization for Gradient Porous Structure of Artificial Bone

2012 ◽  
Vol 271-272 ◽  
pp. 922-926 ◽  
Author(s):  
Yan Mei Qi ◽  
Li Jun Yang ◽  
Li Li Wang
Keyword(s):  
Mechanical Properties ◽  
Porous Structure ◽  
Equivalent Stress ◽  
Strain Analysis ◽  
Equivalent Strain ◽  
Stress And Strain ◽  
Artificial Bone ◽  
Element Analysis ◽  
Maximum Equivalent Stress ◽  
Ansys Workbench

The loading force of the artificial bone implanted into the human body and the flowing, growth and deposition of cells were influenced by the gradient porous structure. The software of ANSYS Workbench was used in the paper for the stress and strain analysis of the gradient porous structure of the established 3D artificial bone. The variation of the maximum equivalent stress and maximum equivalent strain and elastic modulus changed through the changing of the loading force and porosity. Basis on meeting the mechanical properties, the porosity was used as the index for the optimization of the porous structure of the artificial bone. And it also laid the foundation for the subsequent laser sintering.

Mechanical properties and osteoblast proliferation of complex porous dental implants filled with magnesium alloy based on 3D printing

2020 ◽  
pp. 088532822095790
Author(s):  
Xuetao Zhang ◽  
Jian Mao ◽  
Yufeng Zhou ◽  
Fangqiu Ji ◽  
Xianshuai Chen
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloy ◽  
3D Printing ◽  
Porous Structure ◽  
Dental Implants ◽  
Dental Implant ◽  
Alveolar Bone ◽  
Element Analysis ◽  
Weak Part

In this paper, a complex porous dental implant with biodegradable magnesium alloy was designed based on selective laser melting (SLM). Finite element analysis (FEA) was used to simulate the stress distribution of dental implant and alveolar bone in two models of preliminary and later stages of implant. The stress concentration area of dental implants was found not in the porous structure, and the weak part of mechanical properties accords with the work requirements. The porous structure of dental implants can promote the function of cancellous bone in the process of conducting the stress of the dental implant, thus improving the bearing capacity of dental implants. In vitro fatigue experiments were carried out on the experimental samples produced by 3D printing. Through the cell contrast experiment, it was proved that the decomposed Mg2+ could reach the titanium surface smoothly through the porous structure and complete the proliferation of osteoblasts.

scholarly journals Nanostructure, Self-Assembly, Mechanical Properties, and Antioxidant Activity of a Lupin-Derived Peptide Hydrogel

Biomedicines ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 294
Author(s):  
Raffaele Pugliese ◽  
Anna Arnoldi ◽  
Carmen Lammi
Keyword(s):  
Mechanical Properties ◽  
Antioxidant Activity ◽  
Self Assembly ◽  
Antioxidant Activities ◽  
Functional Materials ◽  
Cd Spectroscopy ◽  
Beneficial Effects ◽  
Naturally Occurring ◽  
New Research ◽  
Peptide Hydrogel

Naturally occurring food peptides are frequently used in the life sciences due to their beneficial effects through their impact on specific biochemical pathways. Furthermore, they are often leveraged for applications in areas as diverse as bioengineering, medicine, agriculture, and even fashion. However, progress toward understanding their self-assembling properties as functional materials are often hindered by their long aromatic and charged residue-enriched sequences encrypted in the parent protein sequence. In this study, we elucidate the nanostructure and the hierarchical self-assembly propensity of a lupin-derived peptide which belongs to the α-conglutin (11S globulin, legumin-like protein), with a straightforward N-terminal biotinylated oligoglycine tag-based methodology for controlling the nanostructures, biomechanics, and biological features. Extensive characterization was performed via Circular Dichroism (CD) spectroscopy, Fourier Transform Infrared spectroscopy (FT-IR), rheological measurements, and Atomic Force Microscopy (AFM) analyses. By using the biotin tag, we obtained a thixotropic lupin-derived peptide hydrogel (named BT13) with tunable mechanical properties (from 2 to 11 kPa), without impairing its spontaneous formation of β-sheet secondary structures. Lastly, we demonstrated that this hydrogel has antioxidant activity. Altogether, our findings address multiple challenges associated with the development of naturally occurring food peptide-based hydrogels, offering a new tool to both fine tune the mechanical properties and tailor the antioxidant activities, providing new research directions across food chemistry, biochemistry, and bioengineering.

scholarly journals High elasticity and strength of ultra-thin metallic transition metal dichalcogenides

2021 ◽  
Author(s):  
Ali Sheraz ◽  
Naveed Mehmood ◽  
Mert Mirac Cicek ◽  
İbrahim Ergün ◽  
Hamid Reza Rasouli ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Transition Metal ◽  
Flexible Electronics ◽  
Transition Metal Dichalcogenides ◽  
High Elasticity ◽  
Metal Dichalcogenides

Mechanical properties of transition metal dichalcogenides (TMDCs) are relevant to their prospective applications in flexible electronics. So far, the focus has been on the semiconducting TMDCs, mostly MoX2 and WX2...

Finite Element Analysis of Reinforced Concrete Beams with Exterior FRP Shell

2011 ◽  
Vol 243-249 ◽  
pp. 1461-1465
Author(s):  
Chuan Min Zhang ◽  
Chao He Chen ◽  
Ye Fan Chen
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Test Results ◽  
Contact Interface ◽  
Accurate Calculation ◽  
Element Analysis

The paper makes an analysis of the reinforced concrete beams with exterior FRP Shell in Finite Element, and compares it with the test results. The results show that, by means of this model, mechanical properties of reinforced concrete beams with exterior FRP shell can be predicted better. However, the larger the load, the larger deviation between calculated values and test values. Hence, if more accurate calculation is required, issues of contact interface between the reinforced concrete beams and the FRP shell should be taken into consideration.

Effective Convergence Checks for Verifying Finite Element Stresses at Three-Dimensional Stress Concentrations

2018 ◽  
Vol 3 (3) ◽  
Author(s):  
J. R. Beisheim ◽  
G. B. Sinclair ◽  
P. J. Roache
Keyword(s):  
Finite Element ◽  
Error Estimation ◽  
A Posteriori Error Estimates ◽  
Three Dimensional ◽  
Posteriori Error ◽  
Test Problems ◽  
A Posteriori ◽  
Stress Concentrations ◽  
Element Analysis ◽  
A Posteriori Error

Current computational capabilities facilitate the application of finite element analysis (FEA) to three-dimensional geometries to determine peak stresses. The three-dimensional stress concentrations so quantified are useful in practice provided the discretization error attending their determination with finite elements has been sufficiently controlled. Here, we provide some convergence checks and companion a posteriori error estimates that can be used to verify such three-dimensional FEA, and thus enable engineers to control discretization errors. These checks are designed to promote conservative error estimation. They are applied to twelve three-dimensional test problems that have exact solutions for their peak stresses. Error levels in the FEA of these peak stresses are classified in accordance with: 1–5%, satisfactory; 1/5–1%, good; and <1/5%, excellent. The present convergence checks result in 111 error assessments for the test problems. For these 111, errors are assessed as being at the same level as true exact errors on 99 occasions, one level worse for the other 12. Hence, stress error estimation that is largely reasonably accurate (89%), and otherwise modestly conservative (11%).

scholarly journals Folding photopolymerized origami sheets by post-curing

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Xiaodong He ◽  
Christopher-Denny Matte ◽  
Tsz-Ho Kwok
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Maximum Principal Stress ◽  
Second Step ◽  
Post Processing ◽  
Element Analysis ◽  
Digital Light Processing ◽  
Processing Step ◽  
Lower Maximum

AbstractThe paper presents a novel manufacturing approach to fabricate origami based on 3D printing utilizing digital light processing. Specifically, we propose to leave part of the model uncured during the printing step, and then cure it in the post-processing step to set the shape in a folded configuration. While the cured regions in the first step try to regain their unfolded shape, the regions cured in the second step attempt to keep their folded shape. As a result, the final shape is obtained when both regions’ stresses reach equilibrium. Finite element analysis is performed in ANSYS to obtain the stress distribution on common hinge designs, demonstrating that the square-hinge has a lower maximum principal stress than elliptical and triangle hinges. Based on the square-hinge and rectangular cavity, two variables—the hinge width and the cavity height—are selected as principal variables to construct an empirical model with the final folding angle. In the end, experimental verification shows that the developed method is valid and reliable to realize the proposed deformation and 3D development of 2D hinges.

scholarly journals Biofabrication of Cell-Laden Gelatin Methacryloyl Hydrogels with Incorporation of Silanized Hydroxyapatite by Visible Light Projection

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2354
Author(s):  
Jimmy Jiun-Ming Su ◽  
Chih-Hsin Lin ◽  
Hsuan Chen ◽  
Shyh-Yuan Lee ◽  
Yuan-Min Lin
Keyword(s):  
Mechanical Properties ◽  
Visible Light ◽  
3D Structure ◽  
Three Dimensional ◽  
3D Cell Culture ◽  
Composite Hydrogel ◽  
Digital Light Processing ◽  
Mg63 Cells ◽  
Marrow Mesenchymal Stem Cells ◽  
Low Cytotoxicity

Gelatin methacryloyl (GelMA) hydrogel is a photopolymerizable biomaterial widely used for three-dimensional (3D) cell culture due to its high biocompatibility. However, the drawback of GelMA hydrogel is its poor mechanical properties, which may compromise the feasibility of biofabrication techniques. In this study, a cell-laden GelMA composite hydrogel with a combination incorporating silanized hydroxyapatite (Si-HAp) and a simple and harmless visible light crosslinking system for this hydrogel were developed. The incorporation of Si-HAp into the GelMA hydrogel enhanced the mechanical properties of the composite hydrogel. Moreover, the composite hydrogel exhibited low cytotoxicity and promoted the osteogenic gene expression of embedded MG63 cells and Human bone marrow mesenchymal stem cells (hBMSCs). We also established a maskless lithographic method to fabricate a defined 3D structure under visible light by using a digital light processing projector, and the incorporation of Si-HAp increased the resolution of photolithographic hydrogels. The GelMA-Si-HAp composite hydrogel system can serve as an effective biomaterial in bone regeneration.

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