scholarly journals Promising Bialkali Bismuthides Cs(Na, K)2Bi for High-Performance Nanoscale Electromechanical Devices: Prediction of Mechanical and Anisotropic Elastic Properties under Hydrostatic Tension and Compression and Tunable Auxetic Properties

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2739
Author(s):  
Shahram Yalameha ◽  
Zahra Nourbakhsh ◽  
Ali Ramazani ◽  
Daryoosh Vashaee
Keyword(s):  
Elastic Properties ◽  
Poisson’S Ratio ◽  
High Performance ◽  
Hydrostatic Compression ◽  
Poisson's Ratio ◽  
Elastic Behavior ◽  
Hydrostatic Tension ◽  
Tension And Compression ◽  
Electromechanical Devices ◽  
Anisotropic Elastic

Using first-principles calculations, we predict highly stable cubic bialkali bismuthides Cs(Na, K)2Bi with several technologically important mechanical and anisotropic elastic properties. We investigate the mechanical and anisotropic elastic properties under hydrostatic tension and compression. At zero pressure, CsK2Bi is characterized by elastic anisotropy with maximum and minimum stiffness along the directions of [111] and [100], respectively. Unlike CsK2Bi, CsNa2Bi exhibits almost isotropic elastic behavior at zero pressure. We found that hydrostatic tension and compression change the isotropic and anisotropic mechanical responses of these compounds. Moreover, the auxetic nature of the CsK2Bi compound is tunable under pressure. This compound transforms into a material with a positive Poisson’s ratio under hydrostatic compression, while it holds a large negative Poisson’s ratio of about −0.45 along the [111] direction under hydrostatic tension. An auxetic nature is not observed in CsNa2Bi, and Poisson’s ratio shows completely isotropic behavior under hydrostatic compression. A directional elastic wave velocity analysis shows that hydrostatic pressure effectively changes the propagation pattern of the elastic waves of both compounds and switches the directions of propagation. Cohesive energy, phonon dispersion, and Born–Huang conditions show that these compounds are thermodynamically, mechanically, and dynamically stable, confirming the practical feasibility of their synthesis. The identified mechanisms for controlling the auxetic and anisotropic elastic behavior of these compounds offer a vital feature for designing and developing high-performance nanoscale electromechanical devices.

scholarly journals A Hybrid Artificial Intelligence Model to Predict the Elastic Behavior of Sandstone Rocks

2019 ◽  
Vol 11 (19) ◽  
pp. 5283 ◽  
Author(s):  
Gowida ◽  
Moussa ◽  
Elkatatny ◽  
Ali
Keyword(s):  
Poisson’S Ratio ◽  
Accurate Determination ◽  
Oil And Gas Industry ◽  
Poisson's Ratio ◽  
Elastic Behavior ◽  
Percentage Error ◽  
Ann Model ◽  
Field Development ◽  
Well Completion

Rock mechanical properties play a key role in the optimization process of engineering practices in the oil and gas industry so that better field development decisions can be made. Estimation of these properties is central in well placement, drilling programs, and well completion design. The elastic behavior of rocks can be studied by determining two main parameters: Young’s modulus and Poisson’s ratio. Accurate determination of the Poisson’s ratio helps to estimate the in-situ horizontal stresses and in turn, avoid many critical problems which interrupt drilling operations, such as pipe sticking and wellbore instability issues. Accurate Poisson’s ratio values can be experimentally determined using retrieved core samples under simulated in-situ downhole conditions. However, this technique is time-consuming and economically ineffective, requiring the development of a more effective technique. This study has developed a new generalized model to estimate static Poisson’s ratio values of sandstone rocks using a supervised artificial neural network (ANN). The developed ANN model uses well log data such as bulk density and sonic log as the input parameters to target static Poisson’s ratio values as outputs. Subsequently, the developed ANN model was transformed into a more practical and easier to use white-box mode using an ANN-based empirical equation. Core data (692 data points) and their corresponding petrophysical data were used to train and test the ANN model. The self-adaptive differential evolution (SADE) algorithm was used to fine-tune the parameters of the ANN model to obtain the most accurate results in terms of the highest correlation coefficient (R) and the lowest mean absolute percentage error (MAPE). The results obtained from the optimized ANN model show an excellent agreement with the laboratory measured static Poisson’s ratio, confirming the high accuracy of the developed model. A comparison of the developed ANN-based empirical correlation with the previously developed approaches demonstrates the superiority of the developed correlation in predicting static Poisson’s ratio values with the highest R and the lowest MAPE. The developed correlation performs in a manner far superior to other approaches when validated against unseen field data. The developed ANN-based mathematical model can be used as a robust tool to estimate static Poisson’s ratio without the need to run the ANN model.

scholarly journals Modelling the elastic mechanical properties of bioactive glass-derived scaffolds

2020 ◽  
Vol 6 (1) ◽  
pp. 50-56
Author(s):  
Francesco Baino ◽  
Elisa Fiume
Keyword(s):  
Elastic Properties ◽  
Poisson’S Ratio ◽  
Mechanical Performance ◽  
Solid Material ◽  
Poisson's Ratio ◽  
Predictive Capability ◽  
Shear Moduli ◽  
Wide Range ◽  
Constitutive Parameters ◽  
The Relationship

AbstractPorosity is known to play a pivotal role in dictating the functional properties of biomedical scaffolds, with special reference to mechanical performance. While compressive strength is relatively easy to be experimentally assessed even for brittle ceramic and glass foams, elastic properties are much more difficult to be reliably estimated. Therefore, describing and, hence, predicting the relationship between porosity and elastic properties based only on the constitutive parameters of the solid material is still a challenge. In this work, we quantitatively compare the predictive capability of a set of different models in describing, over a wide range of porosity, the elastic modulus (7 models), shear modulus (3 models) and Poisson’s ratio (7 models) of bioactive silicate glass-derived scaffolds produced by foam replication. For these types of biomedical materials, the porosity dependence of elastic and shear moduli follows a second-order power-law approximation, whereas the relationship between porosity and Poisson’s ratio is well fitted by a linear equation.

High-performance composite with negative Poisson’s ratio

2017 ◽  
Vol 32 (18) ◽  
pp. 3477-3484 ◽  
Author(s):  
Fernanda Steffens ◽  
Fernando Ribeiro Oliveira ◽  
Carlos Mota ◽  
Raul Fangueiro
Keyword(s):  
Poisson’S Ratio ◽  
High Performance ◽  
Poisson's Ratio ◽  
Negative Poisson’S Ratio ◽  
High Performance Composite ◽  
Negative Poisson's Ratio ◽  
Image Position

Abstract

Elastic impedance inversion of multichannel seismic data from unconsolidated sediments containing gas hydrate and free gas

Geophysics ◽  
2004 ◽  
Vol 69 (1) ◽  
pp. 164-179 ◽  
Author(s):  
Shaoming Lu ◽  
George A. McMechan
Keyword(s):  
Elastic Properties ◽  
Gas Hydrate ◽  
Poisson’S Ratio ◽  
P Wave ◽  
Poisson's Ratio ◽  
Unconsolidated Sediments ◽  
Free Gas ◽  
Impedance Inversion ◽  
Elastic Impedance ◽  
New Algorithms

The elastic properties of hydrated sediments are not well‐known, which leads to inaccuracy in the evaluation of the amount of gas hydrate worldwide. Elastic impedance inversion is useful in estimating the elastic properties of sediments containing gas hydrate, or free gas trapped beneath the gas hydrate, from angle‐dependent P‐wave reflections. We reprocess the multichannel U.S. Geological Survey seismic line BT‐1 from the Blake Ridge off the east coast of North America to obtain migrated common‐angle aperture data sets, which are then inverted for elastic impedance. Two new algorithms to estimate P‐impedance and S‐impedance from the elastic impedance are developed and evaluated using well‐log data from Ocean Drilling Program (ODP) Leg 164; these new algorithms are stable, even in the presence of modest noise in the data. The Vs/Vp ratio, Poisson's ratio, and Lamé parameter terms λρ and λ/μ are estimated from the P‐impedance and S‐impedance. The hydrated sediments have high elastic impedance, high P‐impedance, high S‐impedance, high λρ, slightly higher Vs/Vp ratio, slightly lower Poisson's ratio, and slightly lower λ/μ values compared to those of the surrounding unhydrated sediments. The sediments containing free gas have low elastic impedance, low P‐impedance, nonanomalous background S‐impedance, high Vs/Vp ratio, low Poisson's ratio, low λρ, and low λ/μ values. We conclude that some parameters such as Vs/Vp ratio, Poisson's ratio, and λ/μ, although they help identify the free‐gas charged layers, cannot differentiate between the hydrated sediments and nonhydrated sediments when gas hydrate concentration is low, and cannot differentiate between the hydrated sediments and free‐gas charged sediments when the gas hydrate concentration is high. Three distinct layers of gas hydrate are interpreted as being caused by gas hydrates with gas of different molecular weights, with correspondingly different stability zones in depth. Free gas appears to be present below the two deeper gas‐hydrate layers, but not below the shallowest one because the lack of a trapping structure. The gas hydrate has an average concentration of ∼3–5.5% by volume, and is highest (9%) at the base of the lower gas hydrate stability zone. The free‐gas concentration ranges from 1 to 8% by volume, and is most developed beneath the local topographic high of the ocean bottom.

On the analysis and prediction of elastic properties in alkali Na2O–B2O3–V2O5 glasses under the substitution of V2O5 by Na2O

2019 ◽  
Vol 60 (6) ◽  
pp. 213-221
Author(s):  
Amin Abd El-Moneim ◽  
Hassan Y. Alfifi
Keyword(s):  
Elastic Properties ◽  
Dissociation Energy ◽  
Packing Density ◽  
Poisson’S Ratio ◽  
Elastic Moduli ◽  
Unit Volume ◽  
Dominant Role ◽  
Glass Network ◽  
Poisson's Ratio ◽  
Structural Units

In this article, we have continued our recent work(30,42) on the prediction of elastic properties in alkali borovanadate glasses. Changes in the elastic moduli and Poisson’s ratio due to the substitution of V2O5 by Na2O in the ternary alkali Na2O–B2O3–V2O5 glasses have been analysed and predicted on the basis of the theories and approaches that existing in the field. Both the packing density and dissociation energy per unit volume of the glass were evaluated in terms of the basic structural units that constitute the glass network. In addition to this, the theoretical values of elastic moduli and Poisson’s ratio were calculated from the Makishima–Mackenzie’s model and compared with the corresponding experimental values. The results revealed that the concentrations of the basic structural units BO3, BO4, VO5 and VO4 play a dominant role in correcting the anomalous behaviour between experimental elastic moduli and calculated dissociation energy per unit volume. An excellent agreement between the theoretical and experimental elastic moduli was achieved for majority of the samples. The correlation between bulk modulus and the ratio between packing density and mean atomic volume has also been achieved on the basis of Abd El-Moneim and Alfifi’s approaches.

scholarly journals On the identification of the eggshell elastic properties under quasistatic compression

2004 ◽  
Vol 52 (5) ◽  
pp. 73-82 ◽  
Author(s):  
Jana Simeonovová ◽  
Jaroslav Buchar
Keyword(s):  
Young’S Modulus ◽  
Elastic Properties ◽  
Elastic Constants ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
Poisson's Ratio ◽  
Rotational Shell ◽  
Mutual Comparison ◽  
Quasistatic Loading

The problem of the identification of the elastic properties of eggshell, i.e. the evaluation of the Young's modulus and Poisson's ratio is solved. The eggshell is considered as a rotational shell. The experiments on the egg compression under quasistatic loading have been conducted. During these experiments a strain on the eggshell surface has been recorded. By the mutual comparison between experimental and theoretical values of strains the influence of the elastic constants has been demonstrated.

Using multi-dimensional contact mechanics experiments to measure Poisson's ratio of porous low-k films

2003 ◽  
Vol 766 ◽  
Author(s):  
B. N. Lucas ◽  
J. C. Hay ◽  
W. C. Oliver
Keyword(s):  
Integrated Circuits ◽  
Contact Mechanics ◽  
Poisson’S Ratio ◽  
Mechanical Response ◽  
Contact Stiffness ◽  
Poisson's Ratio ◽  
Elastic Behavior ◽  
Structural Effects ◽  
Potential Influence ◽  
Low K

AbstractUsing a new multi-dimensional contact mechanics system, it was recently shown that the experimentally measured tangential to normal stiffness ratio of a contact can be described as a function of the bulk Poisson's ratio of the material as predicted by Mindlin [1-3]. This system has been utilized to measure the normal and tangential elastic contact stiffness of a series of porous low-k films, with increasing starting porogen content. These results indicate a transition from a material-controlled elastic behavior to a structure-controlled elastic behavior as the porosity of the film is increased. These structural effects and their potential influence on the mechanical response to forces imposed on integrated circuits are discussed. The experimental details and apparatus are introduced and described.

Anomalous elastic properties in stishovite

RSC Advances ◽  
2015 ◽  
Vol 5 (12) ◽  
pp. 8974-8980 ◽  
Author(s):  
K. M. Azzopardi ◽  
J. P. Brincat ◽  
J. N. Grima ◽  
Ruben Gatt
Keyword(s):  
Elastic Properties ◽  
Poisson’S Ratio ◽  
Ambient Pressure ◽  
Poisson's Ratio ◽  
Negative Poisson’S Ratio ◽  
Negative Poisson's Ratio

Stishovite exhibits a negative Poisson's ratio when stressed in a range of directions in the (100), (010) and (001) planes under specific ambient pressure ranges. This may be explained through mechanisms involving rotations and distortions of the constituent octahedral.

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