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To study how the soils, respond to an earthquake, seismic waves are frequently utilized. The purpose of this work is to build the porosity graphs based on the geotechnical parameters of the soils and forecast the porosity of shallow clay soils using seismic wave velocities that analyze the dynamic features of the soil. Compressional (P) and shear (S) wave velocities, seismic velocity ratio, Poisson ratio, bulk modulus, and shear modulus are the factors used to calculate porosity. In this work, porosity values are calculated using grain and dry densities of core samples taken from different boreholes within the study region, and bulk modulus, shear modulus, and Poisson ratio are calculated using P- and S-wave velocities obtained by utilizing the seismic-refraction method, as well as porosity values. The research region is in Iran; Isfahan Metro Line 2 and mostly consists of clay, silt, sand, and gravel deposits. Based on the values of the Poisson ratio, seismic P-wave velocity, seismic velocity ratio (Vp/Vs), and the stiffness of the clay soils, the data of the clay soils in the region were individually sorted. These characteristics were used to create novel multi-parameter relationships between clay soil porosity, seismic velocities, shear modulus, and the Poisson ratio. Using the error norm approach, the errors in the parameters utilized for each relationship were identified. The error norm technique's findings show that the shear wave velocity and shear module have the lowest error when calculating porosity. Therefore, it is advised to estimate porosity of shallow clay soils using the given correlations. These relationships can be used to assess the porosity of clay soil and to determine if the soil's pores are saturated with liquid. [ABSTRACT FROM AUTHOR]

Tissues' nearly incompressibility was well reported in the literature but little effort has been made to compare volume variations computed by simulations with in vivo measurements. In this study, volume changes of the fat pad during controlled indentations of the human heel region were estimated from segmented medical images using digital volume correlation. The experiment was reproduced using finite element modelling with several values of Poisson's ratio for the fat pad, from 0.4500 to 0.4999. A single value of Poisson's ratio could not fit all the indentation cases. Estimated volume changes were between 0.9% − 11.7%. [ABSTRACT FROM AUTHOR]

This study investigates the impact of uncertainties in soil properties, particularly the stochastic variations in shear modulus (G) and Poisson's ratio (ν), on the period lengthening ratio (T/T) and base-shear reduction ( Δν/ν) of structures, considering soil-structure interaction (SSI) according to ASCE/SEI 7-10 guidelines. The motivation behind this research is to enhance the understanding and prediction of how uncertainties in soil properties affect the seismic response of structures, aiming at improving building design and safety. This research was conducted using a Monte Carlo simulation approach, generating 500,000 random values for G and ν to evaluate the variations (mean ± standard deviation) in the period lengthening ratio of the soil-foundation- structure system and base-shear reduction. The obtained results indicate that incorporating stochastic variations in the soil properties more accurately reflects the complexity and inherent uncertainty of the soil properties. Specifically, uncertainties in the shear modulus (G) significantly affect the fundamental period, base-shear reduction, and foundation damping. Conversely, the Poisson's ratio (ν) appears to be an inert factor. These findings have implications for seismic-design practices, suggesting that a deterministic approach might not capture critical aspects of material variability, thus contributing to uncertainties in structural response. This study provides critical insights into the role of soil properties in the dynamic response of structures, contributing to the development of more resilient designs and improving seismic risk management strategies. [ABSTRACT FROM AUTHOR]

Carbonate rocks hold considerable volumes of hydrocarbons in various basins around the globe. Understanding the complex pore systems is a key factor in unlocking the potential of carbonate rocks. Matrix properties are also a challenge in carbonate reservoirs. Exploration geoscientists include the regional portfolio targeting the sweet spots for every basin. This study defines the reservoir quality and character of carbonate rocks with scope to the complete carbonate succession of north Western Desert and Abu Gharadig basin (AGB) as one of the most prolific basins in Egypt. More than 301 core samples are used in this study to represent all carbonate rock types. The workflow includes core data classification (grouping), petrographical investigation, reservoir mineralogy, and matrix parameters integrated with well logs and elastic properties. The provided work investigates the effect of pore structure and mineralogy on the petrophysical properties of the rock and its impact on elastic properties as well. Carbonate reservoirs in AGB are divided into three main categories: type-I, type-II, and type-III. Reservoirs enhancement by dolomitization and dissolution are controlling the distribution of pores, which are the key factors to delineate their potential. This study defines the characteristics of each group and the attractive formations for future exploration and development. The main differences in rock type, composition, diagenetic processes, and elastic properties were described. The rock brittleness index was calculated from dynamic properties for each carbonate type to get more insights about the rock brittleness and elasticity and predict variations of each group for future consideration in the basin. [ABSTRACT FROM AUTHOR]

Thermoset resins are singular materials in the field of microelectronics. Because they exhibit a high contrast of thermomechanical properties with other integrated materials like oxides, metals or silicon, polymers can threaten the mechanical integrity of stacks. Knowing polymer properties allows manufacturers to foresee the compatibility between materials and improve chipsets reliability. At a bilayer scale, the properties mismatch between the polymer film and the silicon substrate causes an overall curvature of the wafer which evolves with temperature. By comparing the thermally induced curvature of two distinct substrates with the same film, the biaxial modulus and the coefficient of thermal expansion of the film can be determined. This method can not only check the achievement of the polymer cross-linking, but also estimates their relaxation temperatures. In this article, we present the ability of this method to, not only, measure those properties in the glassy state, but also, for the first time, in the rubbery state. We also illustrate the proficiency of this approach in detecting and characterizing two successive glassy states. [ABSTRACT FROM AUTHOR]

We use coarse-grained molecular dynamics simulations to study deformation of networks and gels of linear and brush strands in both linear and nonlinear deformation regimes under constant pressure conditions. The simulations show that the Poisson ratio of networks and gels could exceed 0.5 in the nonlinear deformation regime. This behavior is due to the ability of the network and gel strands to sustain large reversible deformation, which, in combination with the finite strand extensibility results in strand alignment and monomer density, increases with increasing strand elongation. We developed a nonlinear network and gel deformation model which defines conditions for the Poisson ratio to exceed 0.5. The model predictions are in good agreement with the simulation results. [ABSTRACT FROM AUTHOR]

Crustal structure beneath the major tectonic domains comprising northeast India is investigated using receiver function analyses of teleseismic earthquakes recorded at 19 new broadband seismic stations, combined with Moho depth and Poisson's ratio information from 14 previous studies. Velocity structure inverted from receiver functions are combined with results from H–k stacking and validated using forward modeling of gravity data. The Shillong Plateau in the western Brahmaputra River Valley, later representing the Himalayan foredeep, is inferred to have a thin (33–35 km) felsic crust. A dome-shaped, 5-km-thick high-velocity layer in the upper crust likely accounts for positive Bouguer anomaly over the plateau. The Upper Assam basin in the eastern Brahmaputra River Valley is marked by pronounced gravity low, high Poisson's ratio, and a pair of low- and high-velocity layers in the crust. This narrow segment demarcates the crust of oceanic affinity extending from the Indo-Burmese Wedge. Further to the south of Dauki fault, under the ~ 10-km-thick wedge, a two-layered crust comprising 5–15-km-thick delta sediments overlying a ~ 20-km-thick basement of oceanic affinity extends from Bay of Bengal to the Churachandrapur-Mao Fault, where the deep basement subducts upon collision with the Burmese micro-plate. East of the collision boundary, the overriding Burmese micro-plate having a thin crust of ~ 30 km, including ~ 15-km-thick low-velocity sediments, is imaged beneath Central Myanmar Basin. The findings shed new light on the tectonic reactivation of the different domains of northeast India upon collision with the Himalaya to the north and Burmese micro-plate to the east. [ABSTRACT FROM AUTHOR]

Symmetric Lamb waves with a phase velocity exceeding the expansion wave velocity in an infinite medium are considered. It has been proven that internal waves (i.e., solutions of the wave equation, which have zero values of the strain and stress components on the surface and nonzero values in the plate bulk) may exist in this region of phase velocities. Parameters of the internal waves (phase velocity, frequency, and wavelength) are calculated; it has been proven that frequencies of the internal waves with the same phase velocity make an arithmetic progression. Several internal waves are considered, and cross sections of the corresponding strained plates are presented (as well as the distributions of the maximum tension and shear values). [ABSTRACT FROM AUTHOR]

Poisson's ratio is one of the fundamental characteristics in the material models that are used. In engineering practice, its values are assumed to be constant in the elastic and in the plastic region. In this paper, the conventionally used values of this number for steel materials and aluminum alloys are confronted with experimental results. By using non-contact strain measurements with the DIC (digital image correlation) method, the evolution of the Poisson ratio value in the regions of transition from the elastic to the plastic region as well as in the regions of large plastic deformations was documented. The obtained experimental results are graphically compared using the proposed strain scaling. The gradient of the Poisson ratio changes in the vicinity of the yield stress is significant, indicating the need for a refinement of the material models in this region. Deviations from the conventionally used value of this number were found in the large plastic deformation region. In conclusion, a possible approach for improving the accuracy of simulations in FEM softwares was formulated. [ABSTRACT FROM AUTHOR]

A comprehensive study was conducted to predict the elastic modulus and Poisson ratio of hardened cement pastes (HCPs), including numerical work, comparison of two modelling approaches, and experimental validation. Modelling approach 1 (M1) applied a continuum micromechanics model (CMM) whereas modelling approach 2 (M2) used finite element analysis (FEA). This study presents a reliable method for predicting the mechanical properties of HCPs by firstly employing the microstructures of HCPs, obtained by CEMHYD3D analysis with random distribution of cement particles as input parameters for both M1 and M2 approaches. The elastic modulus and Poisson ratio predicted by M1 and M2 approaches were verified through the experimental data obtained from compressive tests combined with digital image correlation analysis. The elastic moduli of HCPs were significantly affected by the input C-S-H modulus, with 90% of reported C-S-H elastic moduli falling within the range of 20.25 GPa and 30.4 GPa. The predicted elastic moduli of HCPs were well-matched with experimental data when assigning the elastic modulus, bulk modulus, and shear modulus, of C-S-H, as 20.25, 12.98, and 8.17 GPa, respectively. A sensitivity analysis demonstrated a linear increase in the elastic modulus of HCPs with increase of C-S-H modulus, with correlation coefficients R² of 0.9985 and 0.9996 for HCPs with water-to-cement ratios (w/c) of 0.3 and 0.5, respectively. Additionally, the predicted results showed greater consistency at later age (after 7 d) compared to earlier stages. The integral absolute error values of the elastic moduli obtained via M1 and M2 for HCPs with w/c of 0.3 were 6.32% and 6.23%, respectively while those for HCPs with w/c of 0.5 were 4.8% and 5.67%, respectively. M1 approach is more recommended since it is straightforward with time and cost efficiency compared to M2 approach in addition to the suitable prediction accuracy.

Stainless steel (SS) is widely used in many fields including aeronautics, automobiles, marine and mechanical industries due to its outstanding feature such as good corrosion resistance and hardness. However, changes in material properties under stress, particularly changes in Young's modulus, result in the formation of cracks, a reduction in load-bearing capacity, and fatigue damage. So, the structural integrity needs to be evaluated based on a precise measurement of mechanical properties. In this study, Stainless Steel 304 (SS-304) is used as the base material and various tensile stresses are applied ranging from 0 MPa to 100 MPa with increment of 10 MPa in each step. Nondestructive Laser Ultrasound Technique (LUT) has been used to characterize the elastic modulus under various tensile stresses. An inverse program was developed based on the Particle Swarm Optimization (PSO) algorithms to determine material properties. Nonlinear Gauss fitting method was proposed and established the fitting equation and nonlinear curve for Young's modulus and residual stress. The outcome of this research shows that when tensile stress is applied, the mechanical properties decrease by shifting the dispersion curve and also it is evident that the dispersion curves move toward the high-frequency-thickness while increasing the tensile stress. When the tensile stress was increased from 0 MPa to 100 MPa, the value of Young's modulus decreased from 201.7 GPa to 193.5 GPa. Especially, the predominant changes were observed during 30–100 MPa. This observation displays the bonding strength and binding energy between the atomics. Further, the proposed nonlinear Gauss fitting substantiated the experimental values and confirmed that the thickness accuracy is close to the inversion values, with an average difference of 4.32%. This research suggests a potential nondestructive method to determine the residual stress of a material by calculating the changes in the elastic modulus. [ABSTRACT FROM AUTHOR]

Poisson's ratio for earth materials is usually assumed to be positive (Vp/Vs > 1.4). However, this assumption may not be valid in the critical zone because near Earth's surface effective pressures are low (<1 MPa), porosity has a wide range (0%–60%), there are significant texture changes (e.g., unconsolidated vs. fractured media), and saturation ranges from 0% to 100%. We present P‐wave (Vp) and S‐wave (Vs) velocities from seismic refraction profiles collected in weathered crystalline environments in South Carolina and Wyoming. Our data show that ∼20% of the subsurface has negative Poisson's ratios (Vp/Vs values < 1.4), a conclusion supported by borehole sonic logs. The low Vp/Vs values are confined to the fractured bedrock and saprolite. Our data support the hypothesis that weathering‐generated microcracks can produce a negative Poisson's ratio and that Vp/Vs values can thus provide insight into important critical zone weathering processes. Plain Language Summary: When a material is squeezed, the ratio between the change in height and width is described by an elastic parameter called Poisson's ratio. Most earth materials have a positive Poisson ratio, meaning the material will expand when squeezed (e.g., Playdough or wet sand). Materials with a negative Poisson's ratio rarely occurs naturally and will shrink in all directions when squeezed. Cork is a common material with a Poisson's ratio of approximately zero. Cork is ideal for bottling wine because its width does not change when pushing it into the bottle's narrow neck. Here we use surface‐based measurements to quantify Poisson's ratio from P‐wave (Vp) and S‐wave (vs.) velocities in the top 50 m of Earth's surface. Our results show an unexpected result—material in the CZ has a negative Poisson's ratio. We believe this unexpected behavior is caused by the combination of low effective pressures and small and irregular cracks created during rocks' transformation into soil. The cracks have a greater impact on the material's ability to resist compression. At the same time, most of the rock is still coherent and thus only experiences a minimal loss of shear strength. Key Points: Vp/Vs values in the critical zone can be less than 1.4, suggesting a negative Poisson's ratioIn near‐surface environments, the assumption that materials have a positive Poisson ratio is not always justifiedLow Vp/Vs ratios may identify the onset of physical weathering in crystalline rock [ABSTRACT FROM AUTHOR]

This investigation focuses on the experimental determination of critical mechanical properties of various granular materials, namely cement, sand, wheat, granulated sugar, and wheat flour, which are essential in the design of silos. These properties, crucial for defining the behavior of materials stored in silos through numerical methods, have been less documented in existing literature. Conducted at the Research Laboratory of Civil Engineering and Hydraulics of 8 May 1945 University, Guelma, Algeria, a series of geotechnical tests, including triaxial, ring shear, and Oedometric tests, were employed to ascertain a range of properties: internal friction angle, apparent cohesion, specific weight, elastic modulus, Poisson ratio, particle-to-steel wall friction coefficient, and dilatancy angle. It was observed that sand and sugar exhibit the highest rigidity, as indicated by their elastic moduli. In terms of compressibility, sugar, wheat, and wheat flour demonstrated the greatest extent. Discrepancies between the results of triaxial and shear tests suggest a probable influence of material consolidation methods on outcomes. While certain findings aligned with previous studies, discrepancies in materials like cement and sand necessitate additional testing for verification. This study proposes recommended values for these mechanical properties, contributing significantly to the field of silo design. [ABSTRACT FROM AUTHOR]

We use coarse-grained molecular dynamics simulations to study deformation of networks and gels of linear and brush strands in both linear and nonlinear deformation regimes under constant pressure conditions. The simulations show that the Poisson ratio of networks and gels could exceed 0.5 in the nonlinear deformation regime. This behavior is due to the ability of the network and gel strands to sustain large reversible deformation, which, in combination with the finite strand extensibility results in strand alignment and monomer density, increases with increasing strand elongation. We developed a nonlinear network and gel deformation model which defines conditions for the Poisson ratio to exceed 0.5. The model predictions are in good agreement with the simulation results.

The question of the initial misorientation influence of reinforcement direction for resistance to deformation and destruction of standard plane and thin-walled tube-like, with recommended measures, tested samples, made of a layered fiberglass, is considered. The obtained experimental data were analized and generalized from the point of view of optimal design of structural plane and thin-walled tube-like elements from a layered fiberglass on the base of plain weave fiberglass with base coating [ABSTRACT FROM AUTHOR]

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Modern manufacturing is aiming for products that are readily available, environmentally sustainable, and energy efficient. This paper delves into the exploration of compounds meeting these criteria. Specifically, we investigate the structural, elastic, optoelectronic, and transport properties of XSnBr3 (X = Rb/Cs) compounds utilizing the full-potential linearized augmented plane wave program (FP LAPW), a component of Wien2K software. Structural optimization is carried out through the generalized gradient approximation (GGA) approach, yielding lattice constants consistent with preceding numerical and experimental studies. The explored XSnBr3 (X = Rb/Cs) materials exhibit ductility and mechanical stability. Notably, XSnBr3 (X = Rb/Cs) displays a direct bandgap, signifying its semiconducting nature. The bandgap values, as determined by the modified Becke–Johnson (mBJ) approach, stand at 2.07 eV for X = Rb and 2.14 eV for XSnBr3 (X = Rb/Cs). Furthermore, utilizing the BoltzTraP software's transport feature, we investigate thermoelectric properties. Remarkably, XSnBr3 (X = Rb/Cs) demonstrates impressive figures of merit (ZT) at room temperature, implying its potential to serve as a material for highly efficient thermoelectric devices. This research holds promise for contributing to the development of environmentally friendly and energy-efficient technologies. [ABSTRACT FROM AUTHOR]

This article describes calculations of Cauchy pressure pC of the crystalline lattice of alloys (Pettifor criterion), the Pugh ratio (Pugh criterion), and the Poisson ratio (Frantsevich criterion) characterizing plasticity and brittleness of materials. Plasticity of alloys on the basis of titanium nickelide TiNi and brittleness of Ti50Ni50 –xFex (x ≥ 10%) compounds are discussed using the criteria as well as the association of mechanical properties of alloys with the type of chemical bonds between atoms. The coefficient of correlation of TiNi and TiNi–TiFe between the Cauchy pressure pC and the Pugh ratio B/G (cij) is 96.76% (p < 0.001), between pC and B/G (A) is 85.46% (p < 0.05), and between pC and μ is 98.87% (p < 0.001), which signifies a strong statistical correlation between the parameters. [ABSTRACT FROM AUTHOR]

A class of antisymmetric solutions of Lamb wave equations with zero strains and stresses on the surface, so-called internal Lamb waves, is studied. Two types of such solutions are found: the first corresponds to the Lamé phase velocity; the second, to phase velocities exceeding the velocity of the expansion wave in an unbounded medium. It is proved that internal waves with the same phase velocity form series, while the frequencies of members of one series are multiples of the frequency of the first member of the series. The same is true for wavenumbers. The profiles of deformed plates and distributions of the maximum stress and shear values are presented. [ABSTRACT FROM AUTHOR]

Poisson’s ratio is one of the fundamental characteristics in the material models that are used. In engineering practice, its values are assumed to be constant in the elastic and in the plastic region. In this paper, the conventionally used values of this number for steel materials and aluminum alloys are confronted with experimental results. By using non-contact strain measurements with the DIC (digital image correlation) method, the evolution of the Poisson ratio value in the regions of transition from the elastic to the plastic region as well as in the regions of large plastic deformations was documented. The obtained experimental results are graphically compared using the proposed strain scaling. The gradient of the Poisson ratio changes in the vicinity of the yield stress is significant, indicating the need for a refinement of the material models in this region. Deviations from the conventionally used value of this number were found in the large plastic deformation region. In conclusion, a possible approach for improving the accuracy of simulations in FEM softwares was formulated.

Progressive urbanisation causes building users to be affected by increasing amounts of noise and vibrations that come from transportation and other building users. This article presents a test method that can be used to identify quantities of methyl vinyl silicone rubber (VMQ) necessary to carry out solid mechanics finite element method simulations such as Young's modulus, Poisson ratio, and damping parameters. These parameters are necessary to model the vibration isolation used for protection against noise and vibration. The article uses an original combination of dynamic response spectrum and image processing methods to determine these quantities. The tests were carried out using one machine for the range of normal compressive stresses of 64–255 kPa with cylindrical samples of various shape factors in the range of 1–0.25. The parameters for the simulation of solid mechanics in statics were obtained from image processing based on the deformation of the sample under load; for dynamic solid mechanics, the parameters were obtained from the response spectrum of the tested system. The article shows the possibility of determining the given quantities using the original method of the synthesis of dynamic response and FEM-supported image analysis, which states the article's novelty. Additionally, limitations and preferred ranges of sample deformation in terms of load stress and shape factor are presented. [ABSTRACT FROM AUTHOR]

Elastic properties of the solid-state CdTe1−xSex (x= 0-0.5, with Δx= 0.125) solutions within the framework of density functional theory calculations were investigated. The structures of the CdTe1−xSex samples are obtained by the substitution of tellurium with selenium atoms in cubic CdTe. Young's modulus, shear modulus, bulk modulus, and the Poisson ratio of CdTe1−xSex crystals were calculated from the first principles. The dependences of the elastic properties of the CdTe1−xSex solid solution on the content index x within the interval 0 ≤ x ≤ 0.5 are analyzed. According to the Frantsevich rule and the value of the Poisson ratio, the materials have been classified as ductile. The Zener anisotropy factor and the Kleimann parameter are calculated on the basis of the elastic constants Cij. Also, the concentration dependence of longitudinal elastic wave velocity, transverse elastic wave velocity, and average sound velocity, are calculated. Based on the average sound velocity the concentration behavior of the Debye temperature was calculated. The correlation analysis shows a good agreement between the calculation results (elastic modulus and Debye temperature) and known experimental data. [ABSTRACT FROM AUTHOR]

Naturally occurring protein fibers often undergo anisotropic swelling when hydrated. Within a tendon, a hydrated collagen fibril's radius expands by 40% but its length only increases by 5%. The same effect, with a similar relative magnitude, is observed for single hair shafts. Fiber hydration is known to affect elastic properties. Here we show that anisotropic swelling constrains the anisotropic linear elastic properties of fibers. First we show, using data from disparate previously reported studies, that anisotropic swelling can be described as an approximately linear function of water content. Then, under the observation that the elastic energy of swelling can be minimized by the anisotropic shape, we relate swelling anisotropy to elastic anisotropy — assuming radial (transverse) symmetry within a cylindrical geometry. We find an upper bound for the commonly measured axial Poisson ratio ν z x < 1 / 2. This is significantly below recently estimated values for collagen fibrils extracted from tissue-level measurements, but is consistent with both single hair shaft and single collagen fibril mechanical and hydration studies. Using ν z x , we can then constrain the product γ ≡ (1 − ν x y) E z / E x — where ν x y is the seldom measured transverse Poisson ratio and E z / E x is the ratio of axial to radial Young's moduli. [ABSTRACT FROM AUTHOR]

The relationship between transverse and longitudinal deformations (Poisson ratio) in the compressed zone of bending reinforced concrete elements is still not properly considered in designs. This factor is important as it is related to the formation of transverse cracks in the compressed zone of the elements. The main aim of the present research was an experimental investigation of the Poisson ratio in the compressed zone of real single- and two-layer reinforced concrete beams as well as a comparison with the theoretical model proposed in this study. The elastic and elastic–plastic stages were analyzed using experimental data for real beams with a span of 8 m. It was shown that the term "Poisson coefficient" had a limited validity for elastic longitudinal deformations up to 0.5‰. After reaching this limit, the suitable term was "Poisson ratio". The obtained results allowed a more accurate prediction of transverse deformations and the corresponding cracks, defining a new limit state for bending reinforced concrete elements. Therefore, the authors recommend that the obtained results are considered in order to increase the design accuracy of reinforced concrete bending elements. The outcomes of this study and the proposed theoretical concept should be included in modern design provisions. [ABSTRACT FROM AUTHOR]

Modern manufacturing is aiming for products that are readily available, environmentally sustainable, and energy efficient. This paper delves into the exploration of compounds meeting these criteria. Specifically, we investigate the structural, elastic, optoelectronic, and transport properties of XSnBr3 (X = Rb/Cs) compounds utilizing the full-potential linearized augmented plane wave program (FP LAPW), a component of Wien2K software. Structural optimization is carried out through the generalized gradient approximation (GGA) approach, yielding lattice constants consistent with preceding numerical and experimental studies. The explored XSnBr3 (X = Rb/Cs) materials exhibit ductility and mechanical stability. Notably, XSnBr3 (X = Rb/Cs) displays a direct bandgap, signifying its semiconducting nature. The bandgap values, as determined by the modified Becke–Johnson (mBJ) approach, stand at 2.07 eV for X = Rb and 2.14 eV for XSnBr3 (X = Rb/Cs). Furthermore, utilizing the BoltzTraP software’s transport feature, we investigate thermoelectric properties. Remarkably, XSnBr3 (X = Rb/Cs) demonstrates impressive figures of merit (ZT) at room temperature, implying its potential to serve as a material for highly efficient thermoelectric devices. This research holds promise for contributing to the development of environmentally friendly and energy-efficient technologies.

Microstructures, i.e., architected materials, are designed today, typically, by maximizing an objective, such as bulk modulus, subject to a volume constraint. However, in many applications, it is often more appropriate to impose constraints on other physical quantities of interest.In this paper, we consider such generalized microstructural optimization problems where any of the microstructural quantities, namely, bulk, shear, Poisson ratio, or volume, can serve as the objective, while the remaining can serve as constraints. In particular, we propose here a neural-network (NN) framework to solve such problems. The framework relies on the classic density formulation of microstructural optimization, but the density field is represented through the NN’s weights and biases.The main characteristics of the proposed NN framework are: (1) it supports automatic differentiation, eliminating the need for manual sensitivity derivations, (2) smoothing filters are not required due to implicit filtering, (3) the framework can be easily extended to multiple-materials, and (4) a high-resolution microstructural topology can be recovered through a simple post-processing step. The framework is illustrated through a variety of microstructural optimization problems.

We report the absence of auxeticity in CoFe2O4, a magnetic spinel oxide. A CoFe2O4(111) epilayer was grown on the ZnO sacrificial layer, and the in-plane and out-of-plane lattice parameters were precisely determined by X-ray reciprocal space maps. To block the influence from stoichiometry variations, the same CoFe2O4 epilayer was lifted off from the substrate and was used as the reference sample. No auxetic behavior was found, and a positive Poisson ratio of ∼0.32 was obtained. Moreover, the Poisson ratio derived from the compliance coefficients agrees well with our experimental observation. [ABSTRACT FROM AUTHOR]

Pochhammer–Chree axisymmetric waves propagating along an elastic rod with a circular cross section are analytically investigated. The stress-strained state of the rod is considered. Maximum tensile and equivalent stresses arising at the axis and surface of the rod are calculated, and their ratios are determined. Particular attention is given to the medium-wavelength range (wavelengths on the order of the rod radius), and comparison with the short-wave and long-wave approximations is carried out. It is shown that some of the Pochhammer–Chree waves possess a number of unique properties: the relative wavelength is independent of elastic moduli, the ratio of maximum axial tension to maximum surface tension is maximum and also independent of elastic moduli, and the material of the rod is in the simple shear state. It is shown that the waves under consideration belong to the Lamé wave class. [ABSTRACT FROM AUTHOR]

The paper considers the stress-strain state of an elastic unbounded plate during propagation of the fundamental mode of a symmetric Lamb wave. Particular attention is paid to the case of the medium-wavelength range; i.e., wavelength comparable to the thickness of the plate. The stress fields of medium-length waves are compared with the stress fields of the long-wave and short-wave approximations. An internal wave is found for which, for a linear elastic model on the surface of a plate, all strain and stress components, as well as longitudinal displacements, are equal to zero and their localization occurs in the bulk of the plate. This means that surface displacement sensors are inefficient for recording such a wave. It is proved that in this case, the material is in a pure shear state; i.e., the first invariant is zero. [ABSTRACT FROM AUTHOR]

A review of the published data and methods for calculating the Poisson ratio of the TiNi intermetallic compound in the poly- and single-crystal state is performed. The results of our own research are also presented. Significant variability of the presented data is noted, which is due to differences in the thermomechanical processing of the alloys and the measurement and calculation methods used. By averaging the matrices of elastic constants and compliance coefficients using the Voigt, Reuss, and Hill approximations, we obtained the values of the parameters of the effective elastic properties of TiNi polycrystals and calculated the Poisson ratio. Using analytical expressions to calculate the values of the extreme values, the extrema of the Poisson ratio of cubic TiNi crystals are determined for standard orientations. On the basis of a number of data, TiNi crystals are auxetics (materials having negative Poisson ratio values); on the basis of other data, they are not. We found that TiNi crystals belong to the so-called partial auxetics; in this case, the signs of the inequalities (s12 < 0, s = s11 + s12 – s44/2 > 0 or s12 > 0, s = s11 + s12 – s44/2 < 0) are opposite. The values of the Poisson ratio TiNi averaged over the transverse directions of deformation are analyzed. Isosurfaces of the Poisson ratio and their sections are presented using the ELATE computer graphics package and the M-ATHCAD computer algebra program. Aspects of TiNi elastic anisotropy, its parameters, and their relationship to martensitic transformations in TiNi and alloys based on it are discussed. [ABSTRACT FROM AUTHOR]

The study presents a systematic approach for the evaluation of the compression strength of masonry walls composed of heterogeneous mixes of different types of blocks. First of all, the mechanics of a compressed heterogeneous masonry stack is investigated through a series of experimental tests and Finite Element models, then it is reviewed and discussed. Then, the problem of deriving the necessary material parameters entering the Hilsdorf formula is addressed. Solutions for the correct evaluation of the lacking data are presented based on the existing literature data. Finally, the well-known Hilsdorf formula is extended to the field of block blends with different mechanical properties. A deep experimental investigation on stacks and wallets made with fired clay, limestone and sandstone blocks is introduced for the first time. The comparison of the experimental data with the proposed theory points out the very good predictive capability of the extended Hilsdorf formula derived herein. [ABSTRACT FROM AUTHOR]

Betonarme yapıların tasarımında elastik parametreler hesaplanırken betonun esneme direnci ve sağlamlığını göstermesi açısından elastisite modülünün; makaslama direncine karşı betonun gösterdiği mukavemet açısından kayma modülünün ve özellikle betonun suya doygunluk derecesinin belirlenmesi açısından ise Poisson oranının doğru bir şekilde tanımlanması oldukça önemlidir. Betonun elastik parametrelerinin hesaplamaları ulusal veya uluslararası standartlarda bazı kabullere göre yapılırken, dinamik yöntemlerle tahribatsız bir şekilde belirlenen P ve S dalga hız-larından da bu elastik parametreler hesaplanabilmektedir. Bu kapsamda, dinamik yöntemle belirlenen Poisson oran değerleri değişkenlik gösterirken, standartlardaki gibi Poisson oranının 0.20 şeklinde sabit bir değer alınmasının elas-tik parametre hesaplamalarındaki avantaj ve dezavantajlarının ortaya konulması hedeflenmiştir. Bu amaçla, dayanım-ları farklı 12 beton tasarımına ait 108 adet 150x150x150 mm3 ebatlarındaki küp numuneler hazırlanarak P ve S dalga hızları ile Tek eksenli basınç dayanımları belirlenmiştir. Daha sonra, dinamik yöntemlerden elde edilen parametreler kullanılarak hesaplanan elastik parametreler Poisson oranının sabit alınması ile elde edilen parametreler ile karşılaştı-rılmıştır. Belirli zaman aralıklarında yapılan ölçümlerden elde edilen sonuçlar, beton dayanımı ve zamana bağlı olarak elastik parametrelerin değişimini ortaya koymuştur. Ayrıca, Poisson oranının sabit ya da dinamik yöntemle belirlen-diği şekilde değişken olması arasındaki değişimin elastisite ve kayma modülüne etkisi incelenmiştir. Buna göre, Po-isson oranının hesaplamalarda sabit bir değer olarak alınması doğru değildir.

Elastic moduli of {[(TeO2)0.7 (B2O3)0.3]0.8 (SiO2)0.2}1-y (Er2O3 NPs)y glasses with y = 0.01, 0.02, 0.03, 0.04, 0.05 were studied in this work using the theoretical elastic models. The Makishima & Mackenzie, Rocherulle and bond compression models were employed for the study. In the Makishima and Mackenzie model, the packing density was calculated from the bulk glass molar weight and the bulk glass density whereas in Rocherulle model it is determined as the individual oxides. Young, shear and bulk moduli as well as the Poisson ratio were calculated for the glasses in the Makishima and Rocherulle models, while longitudinal, was calculated in addition to young, bulk and shear moduli using the bond compression model. Bond per unit volume number (nb), bulk modulus, bulk modulus ratio (Kbc/Ke), atomic ring size (?) and stretching force constant were also calculated and presented. The values of the Young, bulk and shear moduli obtained from Makishima model increased from 52.854 to 55.335 GPa, 35.754 to 39.862 GPa and 21.080 to 21.809 GPa respectively with Er2O3 NPs composition increase from 1% to 5%.. The Rocherulle model presented increasing values for Young, bulk and shear moduli as 56.910 to 58.432 GPa, 41.452 to 44.450 GPa and 22.385 to 22.809 GPa respectively with Er2O3 NPs composition increase from 1% to 5%. The bond compression model presented much higher values of the elastic moduli compared to the experimentally obtained values and showed an increasing trend as the Er2O3 NPs concentration increases. In the glass network, the atomic ring size value decreased from 0.5698 to 0.5091 nm indicating an increase in the close packing of atoms. Based on the elastic moduli values presented by all the models, Makishima and Mackenzie model presented a more reliable data and hence represents the best model for the studied glass system.

Elastic moduli of f[(TeO2)0:7 (B2O3)0:3]0:8 (SiO2)0:2g1-y (Er2O3 NPs)y glasses with y = 0.01, 0.02, 0.03, 0.04, 0.05 were studied in this work using the theoretical elastic models. The Makishima & Mackenzie, Rocherulle and bond compression models were employed for the study. In the Makishima and Mackenzie model, the packing density was calculated from the bulk glass molar weight and the bulk glass density whereas in Rocherulle model it is determined as the individual oxides. Young, shear and bulk moduli as well as the Poisson ratio were calculated for the glasses in the Makishima and Rocherulle models, while longitudinal, was calculated in addition to young, bulk and shear moduli using the bond compression model. Bond per unit volume number (nb), bulk modulus, bulk modulus ratio (Kbc/Ke), atomic ring size (l) and stretching force constantwere also calculated and presented. The values of the Young, bulk and shear moduli obtained from Makishima model increased from 52.854 to 55.335 GPa, 35.754 to 39.862GPa and 21.080 to 21.809GPa respectively with Er2O3NPs composition increase from 1% to 5%. The Rocherulle model presented increasing values for Young, bulk and shear moduli as 56.910 to 58.432GPa, 41.452 to 44.450 GPa and 22.385 to 22.809 GPa respectively with Er2O3NPs composition increase from 1% to 5%. The bond compression model presented much higher values of the elastic moduli compared to the experimentally obtained values and showed an increasing trend as the Er2O3NPs concentration increases. In the glass network, the atomic ring size value decreased from 0.5698 to 0.5091 nm indicating an increase in the close packing of atoms. Based on the elastic moduli values presented by all the models, Makishima and Mackenzie model presented a more reliable data and hence represents the best model for the studied glass system. [ABSTRACT FROM AUTHOR]

In this study, PAN-based carbon nanofibers (CNFs) were synthesized via electrospinning followed by stabilizing and carbonization. The carbonization process was performed by heating the fibrous mats up to a maximum temperature in the region of 800–1600 °C. The effect of carbonization maximal temperature on the structure and tensile strength of carbon nanofiber mats was investigated via SEM, elemental analysis, X-ray diffraction, Raman spectroscopy and tensile testing. Polyacrylonitrile (PAN) concentrations of 6–10% (w/w) and voltages of 14–16 kV were recognized as the optimal electrospinning parameters in order to synthesize of nanofibrous mats without any agglomerated nanoparticles or beads in the mats structure. It is clear from the results that carbon content, crystalline stacking size (Lc), in-plane crystallite size (La) and the number of graphene layers in single crystallite continuously increased with rising carbonization maximum temperature from 800 to 1600 °C, while interlayer d-spacing (d002) decreased at the maximum temperatures of 1000–1400 °C, firstly. This value increased again at the maximum temperatures above1400 °C due to the formation of considerable shrinkages and pores in the CNFs structure. The highest value of tensile strength (206–223 MPa) was recorded for the CNFs mats carbonized up to 1200–1400 °C. [ABSTRACT FROM AUTHOR]

Resin Concrete uses polymeric resin to replace cement concrete. Four types of polyester resins were identified with Methyl methacrylate as catalyst, calcium carbonate and fly ash as fillers along with river sand and coarse aggregate size of 10mm, 6mm were used to produce resin concrete. Seventytwo trial batches were carried out for preliminary investigation targeting compressive strength of more than 80 MPa (11.6 ksi) and four batches were shortlisted. These four batches along with the addition of glass fiber were taken for detailed investigation of stress strain behavior, young's modulus, Poisson ratio, various correlative equations among their mechanical properties and durability properties. Developed mix can be recommended for manufacturing various polymer products. [ABSTRACT FROM AUTHOR]

The relationship between transverse and longitudinal deformations (Poisson ratio) in the compressed zone of bending reinforced concrete elements is still not properly considered in designs. This factor is important as it is related to the formation of transverse cracks in the compressed zone of the elements. The main aim of the present research was an experimental investigation of the Poisson ratio in the compressed zone of real single- and two-layer reinforced concrete beams as well as a comparison with the theoretical model proposed in this study. The elastic and elastic–plastic stages were analyzed using experimental data for real beams with a span of 8 m. It was shown that the term “Poisson coefficient” had a limited validity for elastic longitudinal deformations up to 0.5‰. After reaching this limit, the suitable term was “Poisson ratio”. The obtained results allowed a more accurate prediction of transverse deformations and the corresponding cracks, defining a new limit state for bending reinforced concrete elements. Therefore, the authors recommend that the obtained results are considered in order to increase the design accuracy of reinforced concrete bending elements. The outcomes of this study and the proposed theoretical concept should be included in modern design provisions.

Europium-doped magnesium–zinc–sulfophosphate glasses of molar composition (65 − x) P2O5–20MgO–15ZnSO4–xEu2O3 (x = 0.0, 0.5, 1.0, 1.5 and 2.0) were prepared via melt-quenching method. The synthesized glasses were characterized at room temperature to determine the relationship between Racah and mechanical properties. The FTIR spectra of glasses in the range of 4000–400 cm−1 revealed the presence of characteristic functional groups. The Young's, shear and bulk moduli of glasses were observed to enhance with the increase in Eu3+ contents. The ratio increased from 0.710 to 0.747 which confirms the increase in the degree of centrality of the glasses. Racah parameters evaluated from first three major absorption bands were reduced from 72.3906 to 60.1111 cm−1 with the increase in Europium contents, thus signifying the weakening in f–f electrons repulsion. Crystal field parameters decrease from 42.2445 to 35.2397 cm−1 denoting strong covalent character of ligand bond of the synthesized glass system. The synthesized glasses have potential for the development of hard surface engineering. [ABSTRACT FROM AUTHOR]

The compressive and tensile moduli of asphalt mixtures are not equal. As a result, in order to obtain reasonable response calculation results, asphalt pavement mechanical analysis should first determine the compressive and tensile moduli of asphalt mixtures separately. Then, it should assign an appropriate modulus to the FEM element based on the stress state of the element. However, conventional uniaxial compression modulus testing protocol is typically unable to determine the actual asphalt pavement's coring specimen due to the limitation that general dynamic modulus testing protocol requires a larger size of specimen and conventional coring specimen from field usually cannot meet the requirement in regard to specimen size. In this case, the dynamic modulus of the asphalt mixture can only be ascertained using the IDT test method. Nevertheless, the current IDT test protocol is unable to distinguish between the compressive and tensile moduli of asphalt mixtures, and the testing results are usually different from those obtained by using the conventional uniaxial compression or tension method. This is because the current IDT test method for determining the dynamic modulus of asphalt mixtures generally treats asphalt mixtures as a kind of ideal elastic material and considers its compressive modulus is equal to its tensile modulus. Consequently, this paper presents a new theory, based on Ambartsumyan's bi-modulus constitutive relation theory, that can use the IDT test method to simultaneously determine the dynamic modulus of an asphalt mixture in both compression and tension. This theory assumes that the stress-strain relationship of asphalt mixture complies with the bi-modulus constitutive relation, and obtains the vertical deformation or horizontal deformation of the IDT specimen by solving a definite integral for the displacement of a small segment on the vertical or horizontal axis, which utilizes the results of the mathematical analysis of the stress distribution of the IDT specimen under distributed strip load. Then, the specimen's dynamic modulus in compression and tension can be obtained via back-calculating method, if the specimen's vertical and horizontal displacement are measured by a physical test in the lab. Obviously, this theory addresses the limitation of the conventional IDT method that cannot reflect the distinction of compressive modulus with tensile modulus, and can be better utilized to simultaneously determine compressive and tensile modulus of cored specimen from field. The verification test also demonstrates, the dynamic modulus determined by this theory are in line with the results of the conventional uniaxial test and is highly practicable. [Display omitted] • Thetheory acquires more accurate results thanconventional IDT method to determine tensile and compressive modulus. • The dynamic modulus determined by this theory is consistent well with conventional uniaxial test results. • The compressive modulus of asphalt mixture is significantly greater than its tensile modulus when temperatures are higher. [ABSTRACT FROM AUTHOR]

A brief review is given of the effect of porosity on the Poisson ratio of a porous material. In contrast to elastic moduli such as K, G, or E, which always decrease with the addition of pores into a matrix, the Poisson ratio ν may increase, decrease, or remain the same, depending on the shape of the pores, and on the Poisson ratio of the matrix phase, ν o . In general, for a given pore shape, there is a unique critical Poisson ratio, ν c , such that the addition of pores into the matrix will cause the Poisson ratio to increase if ν o < ν c , decrease if ν o > ν c , and remain unchanged if ν o = ν c . The critical Poisson ratio for spherical pores is 0.2, for prolate spheroidal pores is close to 0.2, and tends toward zero for thin cracks. For two-dimensional materials, ν c = 1 / 3 for circular pores, 0.306 for squares, 0.227 for equilateral triangles, and again approaches 0 for thin cracks. The presence of a "trapped" fluid in the pore space tends to cause ν c to increase, and for the range of parameters that may occur in rocks or concrete, this increase is more pronounced for thin crack-like pores than for equi-dimensional pores. Measurements of the Poisson ratio therefore may allow insight into pore geometry and pore fluid. If the matrix phase is strongly auxetic, small amounts of porosity will generally not cause the Poisson ratio to become positive. [ABSTRACT FROM AUTHOR]