scholarly journals Structural deformation and mechanical response of CrS2, CrSe2 and Janus CrSSe

2021 ◽  
Author(s):  
Shambhu Bhandari Sharma ◽  
Ramesh Paudel ◽  
Rajendra Adhikari ◽  
Gopi Chandra Kaphle ◽  
Durga Paudyal
Keyword(s):  
Poisson’S Ratio ◽  
Density Functional ◽  
Tensile Strain ◽  
Mechanical Response ◽  
Axial Stress ◽  
Covalent Bond ◽  
Poisson's Ratio ◽  
Structural Deformation ◽  
Plastic Behavior ◽  
Potential Candidate

In the framework of density functional theory (DFT), we investigate the structural deformation, and mechanical behavior of the Janus CrSSe, which has out-of-plane structural asymmetry, with conventional transition metal dichalcogenides (TMDs) CrS2 and CrSe2 . The Janus CrSSe could be a potential candidate for machinable optoelectronic and piezoelectric applications. We predict that these compounds are chemically, mechanically, and dynamically stable with the covalent bond between the TM(Cr) and chalcogen(X=S, Se) atoms. Due to the influence of tensile strain, the Cr-X bond length of each monolayers increases, and the thickness decreases. Interestingly, the in-plane stiffness, shear and layer moduli, Poisson’s ratio, ultimate bi/uni-axial stress of Janus CrSSe are in between the values of CrS2 and CrSe2 monolayers. Similar to TMDs, the orientation-dependent in-plane stiffness and Poisson’s ratio demonstrate the isotropic behavior in Janus CrSSe. Furthermore, it can sustain a larger value of uni/bi-axial tensile strain with the critical strain equivalent to CrX2 monolayers. By applying higher-order strain, we have also found average elastic-plastic behavior as expected. These findings demonstrate that the Janus CrSSe monolayer is a mechanically stable and ductile compound that maintains the hybrid behavior.

Thermo-Elasto-Plastic Analysis of Thick-Walled Spherical Pressure Vessels Made of Functionally Graded Materials

2016 ◽  
Vol 08 (04) ◽  
pp. 1650054 ◽  
Author(s):  
Zeinab Mazarei ◽  
Mohammad Zamani Nejad ◽  
Amin Hadi
Keyword(s):  
Heat Flux ◽  
Functionally Graded Materials ◽  
Poisson’S Ratio ◽  
Pressure Vessels ◽  
Functionally Graded ◽  
Material Behavior ◽  
Poisson's Ratio ◽  
Uniform Heat Flux ◽  
Plastic Behavior ◽  
Graded Materials

An exact closed-form analytical solution is presented to solve the thermo-elasto-plastic problem of thick-walled spherical vessels made of functionally graded materials (FGMs). Assuming that the inner surface is exposed to a uniform heat flux, and that the outer surface is exposed to an airstream. The heat conduction equation for the one-dimensional problem in spherical coordinates is used to obtain temperature distribution in the sphere. Material properties are graded in the thickness direction according to a power law distribution, whereas the Poisson’s ratio is kept constant. The Poisson’s ratio due to slight variations in engineering materials is assumed constant. The plastic model is based on von Mises yield criterion and its associated flow rules under the assumption of perfectly plastic material behavior. For various values of inhomogeneity constant, the so-obtained solution is then used to study the distribution of limit heat flux, displacement and stresses versus the radial direction. Moreover, the effect of increasing the heat flux and pressure on the propagation of the plastic zone are investigated. Furthermore, the effect of change in Poisson’s ratio on the value of the critical material parameter is demonstrated. The present study is also validated by comparing the numerical results for thick elasto-plastic spherical shells available in the literature. To the best of the authors’ knowledge, in previous studies, exact thermo-elasto-plastic behavior of FGM thick-walled sphrical pressure vessels has not investigated.

Metamaterials with enhanced mechanical properties and tuneable Poisson’s ratio

2021 ◽  
Author(s):  
Amer Alomarah ◽  
Syed Masood ◽  
Dong Ruan
Keyword(s):  
Poisson’S Ratio ◽  
Structural Modification ◽  
Mechanical Response ◽  
Good Alternative ◽  
Poisson's Ratio ◽  
Polyamide 12 ◽  
Loading Direction ◽  
Wide Range ◽  
Potential Applications ◽  
Parametric Studies

Abstract This paper reports a structural modification of an auxetic metamaterial with a combination of representative re-entrant and chiral topologies, namely, a re-entrant chiral auxetic (RCA). The main driving force for the structural modification was to overcome the undesirable properties of the RCA metamaterial such as anisotropic mechanical response under uniaxial compression. Additively manufactured polyamide 12 specimens via Multi Jet Fusion (MJF) were quasi-statically compressed along the two in-plane directions. The experimental results confirmed that the modified structure was less sensitive to the loading direction and the deformation was more uniform. Moreover, similar energy absorptions were obtained when the modified metamaterial was crushed along the two in-plane directions. The energy absorptions were improved from 390 to 950 kJ/m³ and from 500 to 1000 kJ/m³ compared with the RCA when they were crushed along the X and Y directions, respectively. The absorbed energy per unit mass (SEA) also improved from 1.4 to 2.9 J/g and from 1.78 to 3.1 J/g compared with that of the RCA under the axial compression along the X and Y directions. Furthermore, parametric studies were performed and the effects of geometric parameters of the modified metamaterial were numerically investigated. Tuneable auxetic feature was obtained. The energy absorption and Poisson’s ratio of the modified metamaterial offer it a good alternative for a wide range of potential applications in the areas such as aerospace, automotive, and human protective equipment.

Measurement of Cement in Situ Stresses and Mechanical Properties Without Cooling or Depressurization

2021 ◽  
Author(s):  
Meng Meng ◽  
Luke Frash ◽  
James Carey ◽  
Wenfeng Li ◽  
Nathan Welch ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Elastic Modulus ◽  
Poisson’S Ratio ◽  
Axial Stress ◽  
Triaxial Compression ◽  
In Situ Measurement ◽  
Poisson's Ratio ◽  
Ambient Conditions

Abstract Accurate characterization of oilwell cement mechanical properties is a prerequisite for maintaining long-term wellbore integrity. The drawback of the most widely used technique is unable to measure the mechanical property under in situ curing environment. We developed a high pressure and high temperature vessel that can hydrate cement under downhole conditions and directly measure its elastic modulus and Poisson's ratio at any interested time point without cooling or depressurization. The equipment has been validated by using water and a reasonable bulk modulus of 2.37 GPa was captured. Neat Class G cement was hydrated in this equipment for seven days under axial stress of 40 MPa, and an in situ measurement in the elastic range shows elastic modulus of 37.3 GPa and Poisson's ratio of 0.15. After that, the specimen was taken out from the vessel, and setted up in the triaxial compression platform. Under a similar confining pressure condition, elastic modulus was 23.6 GPa and Possion's ratio was 0.26. We also measured the properties of cement with the same batch of the slurry but cured under ambient conditions. The elastic modulus was 1.63 GPa, and Poisson's ratio was 0.085. Therefore, we found that the curing condition is significant to cement mechanical property, and the traditional cooling or depressurization method could provide mechanical properties that were quite different (50% difference) from the in situ measurement.

scholarly journals Poisson‘s Ratio Induced Radial Inertia Confinement During Dynamic Compression of Hyperelastic Foams

2018 ◽  
Vol 183 ◽  
pp. 02007
Author(s):  
Brett Sanborn ◽  
Bo Song ◽  
Wei-Yang Lu
Keyword(s):  
Poisson’S Ratio ◽  
Dynamic Compression ◽  
Axial Stress ◽  
Soft Materials ◽  
High Rate ◽  
Poisson's Ratio ◽  
Inertia Effects ◽  
Silicone Foam ◽  
Axial Acceleration ◽  
Radial Inertia

Hyperelastic foams have excellent impact energy absorption capability and can experience full recovery following impact loading. Consequently, hyperelastic foams are selected for different applications as shock isolators. Obtaining accurate intrinsic dynamic compressive properties of the hyperelastic foams has become a crucial step in shock isolation design and evaluation. Radial inertia is a key issue in dynamic characterization of soft materials. Radial inertia induced stress in the sample is generally caused by axial acceleration and large deformation applied to a soft specimen. In this study, Poisson’s ratio of a typical hyperelastic foam – silicone foam – was experimentally characterized under high strain rate loading and was observed to drastically change across the densification process. A transition in the Poisson’s ratio of the silicone foam specimen during dynamic compression generated radial inertia which consequently resulted in additional axial stress in the silicone foam sample. A new analytical method was developed to address the Poisson’s ratio-induced radial inertia effects for hyperelastic foams during high rate compression.

scholarly journals Design and Prediction of a Novel Two-Dimensional Carbon Nanostructure with In-Plane Negative Poisson’s Ratio

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Kun Yuan ◽  
Meng-Yang Li ◽  
Yan-Zhi Liu ◽  
Ren-Zhong Li
Keyword(s):  
Mechanical Properties ◽  
Poisson’S Ratio ◽  
Density Functional ◽  
Mechanical Stability ◽  
Poisson's Ratio ◽  
Negative Poisson’S Ratio ◽  
Two Dimensional ◽  
Carbon Nanostructure ◽  
Ratio Effect ◽  
Negative Poisson's Ratio

The intrinsic negative Poisson’s ratio effect in 2-dimensional nanomaterials have attracted a lot of research interests due to its superior mechanical properties, and new mechanisms have emerged in the nanoscale. In this paper, we designed a novel graphyne-like two-dimensional carbon nanostructure with a “butterfly” shape (GL-2D-1) and its configuration isomer with a “herring-bone” form (GL-2D-2) by means of density functional theoretical calculation and predicted their in-plane negative Poisson’s ratio effect and other mechanical properties. Both GL-2D-1 and GL-2D-2 present a significant negative Poisson’s ratio effect under different specific strains conditions. By contrast, GL-2D-2 presents a much stronger negative Poisson’s ratio effect and mechanical stability than does GL-2D-1. It is hoped that this work could be a useful structural design strategy for the development of the 2D carbon nanostructure with the intrinsic negative Poisson’s ratio.

scholarly journals Stable planar single-layer hexagonal silicene under tensile strain and its anomalous Poisson's ratio

2014 ◽  
Vol 104 (8) ◽  
pp. 081902 ◽  
Author(s):  
Baolin Wang ◽  
Jiangtao Wu ◽  
Xiaokun Gu ◽  
Hanqing Yin ◽  
Yujie Wei ◽  
...  
Keyword(s):  
Poisson’S Ratio ◽  
Tensile Strain ◽  
Single Layer ◽  
Poisson's Ratio

Characterization of the Mechanical Properties of Monolayer Molybdenum Disulfide Nanosheets Using First Principles

2013 ◽  
Vol 4 (3) ◽  
Author(s):  
R. Ansari ◽  
S. Malakpour ◽  
M. Faghihnasiri ◽  
S. Ajori
Keyword(s):  
Mechanical Properties ◽  
Molybdenum Disulfide ◽  
Poisson’S Ratio ◽  
Density Functional ◽  
Hexagonal Boron Nitride ◽  
Axial Strain ◽  
Poisson's Ratio ◽  
Generalized Gradient ◽  
Shear Moduli ◽  
Molybdenum Disulfide Nanosheets

Recently, synthesized inorganic two-dimensional monolayer nanostructures are very promising to be applied in electronic devices. This article explores the mechanical properties of a monolayer molybdenum disulfide (MoS2) including Young's bulk and shear moduli and Poisson's ratio by applying density functional theory (DFT) calculation based on the generalized gradient approximation (GGA). The results demonstrate that the elastic properties of MoS2 nanosheets are less than those of graphene and hexagonal boron-nitride (h-BN) nanosheets. However, their Poisson's ratio is found to be higher than that of graphene and h-BN nanosheet. It is also observed that due to the special structure of MoS2, the thickness of nanosheet changes when the axial strain is applied.

scholarly journals First principle study of structural, elastic, electronic and optical properties of Pb0.5Sn0.5TiO3 and Pb0.5Sn0.5Ti0.5(Zr0.5)O3

2021 ◽  
Vol 24 (1) ◽  
pp. 13702
Author(s):  
S.G. Kuma ◽  
M.M. Woldemariam
Keyword(s):  
Optical Properties ◽  
Elastic Modulus ◽  
Poisson’S Ratio ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Theoretical Data ◽  
Poisson's Ratio ◽  
Modern Theory ◽  
Generalized Gradient ◽  
Electronic Band

The structural, electronic, elastic and optical properties of tetragonal (P4mm) phase of Pb0.5Sn0.5TiO3 (PSTO) and Pb0.5Sn0.5Ti0.5(Zr0.5)O3 (PSTZO) are examined by first-principles calculations based on the density functional theory (DFT) using the pseudo-potential plane wave (PP-PW) scheme in the frame of generalized gradient approximation (GGA). We have calculated the ground state properties such as equlibrium lattice constants, volume, bulk modulus and its pressure derivative. From elastic constants, mechanical parameters such as anisotropy factor, elastic modulus and Poisson's ratio are obtained from the Voigt-Reuss-Hill average approximation. Rather than their averages, the directional dependence of elastic modulus, and Poisson's ratio are modelled and visualized in the light of the elastic properties of both systems. In addition, some novel results, such as Debye temperatures, and sound velocities are obtained. Moreover, we have presented the results of the electronic band structure, densities of states and charge densities. These results were in favourable agreement with the existing theoretical data. The optical dielectric function and energy loss spectrum of both systems are also computed. Born effective charge (BEC) of each atoms for both systems is computed from functional perturbation theory (DFPT). Finally, the spontaneous polarization is also determined from modern theory of polarization to be 0.8662 C/m2 (PSTO) and 1.0824 C/m2 (PSTZO).

scholarly journals Strain driven negative Poisson's ratio and extraordinary light-harvesting response of Penta-BCN monolayer

2021 ◽  
Author(s):  
Shambhu Bhandari Sharma ◽  
Ramchandra Bhatta ◽  
Rajendra Adhikari ◽  
Durga Paudyal
Keyword(s):  
Poisson’S Ratio ◽  
Density Functional ◽  
Compressive Strain ◽  
Optical Response ◽  
Mechanical Anisotropy ◽  
Poisson's Ratio ◽  
Visible Range ◽  
Negative Poisson’S Ratio ◽  
Structural Dynamic ◽  
Negative Poisson's Ratio

We report here, structural, dynamic, and mechanical stability in pentagonal boron carbon nitride (p-BCN) monolayer, a new member of direct bandgap two-dimensional (2D) semiconductor. The identified visible range bandgap with excellent mechanical strength allows it to be a promising candidate material in optoelectronics and nanomechanics. By employing density functional theory (DFT), we reveal a unique geometrical reconstruction with rigidity in B$ - $N and C$ - $N bond lengths with applied strain. These quasi-sp$ ^3$ hybridized short and strong covalent bonding and unique geometry support the monolayer to possess extraordinary mechanical response. Remarkably, the very rare, negative Poisson's ratio (NPR), with softening and hardening, mechanical anisotropy to isotropy is achieved with the application of a small value of strain. Similarly, the desired bandgap is manipulated by loading the biaxial strain. Most importantly, our predictions on p-BCN show excellent optical response such as good static dielectric constant and refractive index, strong optical absorption (up to 1.08$\times$10$ ^5 $ $ {cm}^{-1}$ in VR and 7.01$\times$10$ ^5 $ $ {cm}^{-1}$ in UV) with small energy loss and reflectance both appearing in visible and ultraviolet regions (UV). The desired optical response along with the blue and red shift is demonstrated by tailoring with tensile and compressive strain. Additionally, the predicted strong optical anisotropy provides it's application in polarized photodetection.

DFT study of SmXO3 (X = Al and Co) for elastic, mechanical and optical properties

2018 ◽  
Vol 32 (32) ◽  
pp. 1850362 ◽  
Author(s):  
A. Afaq ◽  
Abu Bakar ◽  
Sajid Anwar ◽  
Waheed Anwar ◽  
Fazal-e-Aleem
Keyword(s):  
Optical Properties ◽  
Poisson’S Ratio ◽  
Density Functional ◽  
Structural Parameters ◽  
Poisson's Ratio ◽  
Published Data ◽  
Generalized Gradient ◽  
Elastic Parameters ◽  
Functional Theory ◽  
Anisotropic Factor

The first-principles study of cubic perovskites SmXO3 (X = Al and Co) for elastic, mechanical and optical properties is done in the framework of density functional theory (DFT). Optimized structural parameters are obtained first to find mechanical and optical properties of the materials. These obtained structural parameters are in accordance with the published data. The cubic elastic parameters C[Formula: see text], C[Formula: see text] and C[Formula: see text] are then calculated by using generalized gradient approximation (GGA) as an exchange correlation functional in Kohn–Sham equations. Poisson’s ratio, shear modulus, Young’s modulus and anisotropic factor are deduced from these elastic parameters. These compounds are found to be elastically anisotropic and SmAlO3 is brittle while SmCoO3 is ductile. Their covalent nature is also discussed by using Poisson’s ratio. In addition, optical properties like absorption coefficient, extinction coefficient, energy loss function, dielectric function, refractive index, reflectivity and optical conductivity are studied. This study predicts that SmAlO3 and SmCoO3 are suitable for optoelectronic devices.

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