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The physical and mechanical properties and structural condition of flexible graphite foils produced by processing natural graphite with nitric acid, hydrolysis, thermal expansion of graphite and subsequent rolling were studied. The processes of obtaining materials and changing their characteristics has been thoroughly described and demonstrated. The structural transformations of graphite in the manufacture of foils were studied by X-ray diffraction analysis (XRD) and transmission electron microscopy (TEM). A decrease in the average size of the coherent scattering regions (CSR) of nanocrystallites was revealed during the transition from natural graphite to thermally expanded graphite from 57.3 nm to 20.5 nm at a temperature of 900 °C. The rolling pressure ranged from 0.05 MPa to 72.5 MPa. The thickness of the flexible graphite foils varied from 0.11 mm to 0.75 mm, the density—from 0.70 to 1.75 g/cm3. It was shown that with an increase in density within these limits, the compressibility of the graphite foil decreased from 65% to 9%, the recoverability increased from 5% to 60%, and the resiliency decreased from 10% to 6%, which is explained by the structural features of nanocrystallites. The properties' anisotropy of graphite foils was studied. The tensile strength increased with increasing density from 3.0 MPa (ρ = 0.7 g/cm3) to 14.0 MPa (ρ = 1.75 g/cm3) both in the rolling direction L and across T. At the same time, the anisotropy of physical and mechanical properties increased with an increase in density along L and T to 12% with absolute values of 14.0 MPa against 12.5 MPa at a thickness of 200 μm. Expressed anisotropy was observed along L and T when studying the misorientation angles of nanocrystallites: at ρ = 0.7 g/cm3, it was from 13.4° to 14.4° (up to 5% at the same thickness); at ρ = 1.3 g/cm3—from 11.0° to 12.8° (up to 7%); at ρ = 1.75 g/cm3—from 10.9° to 12.4° (up to 11%). It was found that in graphite foils, there was an increase in the coherent scattering regions in nanocrystallites with an increase in density from 24.8 nm to 49.6 nm. The observed effect can be explained by the coagulation of nanocrystallites by enhancing the Van der Waals interaction between the surface planes of coaxial nanocrystallites, which is accompanied by an increase in microstrains. The results obtained can help discover the mechanism of deformation of porous graphite foils. The obtained results can help discover the deformation mechanism of porous graphite foils. We assume that this will help predict the material behavior under industrial operating conditions of products based flexible graphite foils. [ABSTRACT FROM AUTHOR]

Purpose: The article presents a procedure for modelling and analysing a model system of ring and cone springs, in their particular material solution, using selected polymeric materials. Design/methodology/approach: Subsequently, physical and mathematical models were presented, allowing the formulation of general design assumptions for the target products. The material models made were subjected to experimental tests to evaluate the correctness of the analytical models. Commercially available types of pure polyethylene and polypropylene were used as materials for machined parts based on catalogue properties. The material models were tested under variable static and periodically varying dynamic loads. The constructed finite element model was subjected to verification of the compatibility of the results of the numerical analysis with the results of simple experiments in order to assess the correctness of the model. Practical implications: The correctness and adequacy of the computational model, confirmed in terms of simple load cases, will allow extending the scope of numerical simulation studies to systems that differ in material and geometric design features. Originality/value: The performed studies have proved the advisability of using polymeric materials in the area of the design of ring springs. It allows for the significant expansion of the area of static and dynamic characteristics, which opens new fields of application for similar solutions. Due to the developed and verified numerical model, it becomes possible to analyse similar structural elements in terms of materials and geometry. In particular, interesting results can be expected if the research area is extended to composite materials. Also, the specific properties of plastics make it possible to expand the rationale field for similar systems. The prices of the tested materials and, above all, the cost of processing in the presented structural solutions are competitive in cases where it is possible to obtain similar technical characteristics as steel structures. In addition, a wide range of design requirements can be met exclusively by polymer or composite springs. The tools presented here open up new possibilities for computer-aided design processes. [ABSTRACT FROM AUTHOR]

All-solid-state batteries (ASSBs) are the important attributes of the forthcoming technologies for electrochemical energy storage. A key element of ASSBs is the solid electrolyte materials. Garnets are considered promising candidates for solid electrolytes of ASSBs due to their chemical stability with Li metal anodes, reasonable kinetic characteristics (σ L i ∼ 10 − 3 –10 − 4 S · cm − 1 ) and a wide electrochemical window. This study is aimed at the analysis of the experimental data available for garnet thin films, examining the ionic conductivity through the film/substrate lattice mismatch, the elastic properties and the difference in the thermal expansion characteristics of the film and the substrate, the deposition temperature of the film, and the melting point and the dielectric constant of the substrate. Based on the results of this analysis and by introducing the corresponding characteristics involved as the descriptors, the quantitative models for predicting the ionic conductivity values were developed. Some important characteristic features for ion transport in garnet films, which are primarily concerned with the film/substrate misfit, elastic properties, deposition temperature, cation segregation and the space charge effects, are discussed. [ABSTRACT FROM AUTHOR]

The effect of short carbon fiber (SCF) filler on the mechanical properties of 3D-printed acrylonitrile butadiene styrene (ABS) was investigated. The fused filament fabrication (FFF) method was used for the manufacturing of samples. Elastic properties and strength characteristics of samples made of conventional ABS and SCF-reinforced ABS were compared in tensile and bending tests. Fracture toughness and critical strain energy release rate were also determined. In addition, 3D-printed monofilament SCF-reinforced samples were fabricated, the internal structure of which was analyzed using microcomputed tomography (micro-CT). Based on the tomography data, finite-element (FE) models of representative volume elements (RVEs) of the reinforced material were created and used for the numerical calculation of effective characteristics. Numerical and experimental results for the effective elastic properties were compared with the Mori-Tanaka homogenization technique. The ABS samples filled with SCF showed considerably higher mechanical characteristics than those of the conventional ABS. Finally, the dependence between the strength characteristics and elastic properties of the samples on the diameter of the nozzle used for 3D printing was established. 3D-printed ABS reinforced with SCF demonstrated a gain in tensile strength and fracture toughness by 30% and 20%, respectively. Interlayer adhesion strength in flexure tests showed an increase of 28% compared to pure ABS samples. [ABSTRACT FROM AUTHOR]

To establish a collision model of wheat grains impacting a force plate with a piezoelectric sensor, and to investigate the influence of the elastic recovery coefficient on the sensor's detection accuracy during the collision process, this study employed object kinematic principles to construct a wheat elastic recovery coefficient measurement device. This device ascertains the elastic properties of wheat during collisions and determines the elastic recovery coefficient of the wheat collision model. The wheat variety Jinan No. 17 was selected for testing, and the effects of the contact material, grain drop height, material thickness, and grain moisture content on the collision recovery coefficient during the collision process were analyzed through single-factor and multi-factor experiments. The experimental results demonstrate that the collision recovery coefficient of wheat grains increases with the stiffness of the collision materials for different materials. The grain recovery coefficient of wheat exhibits a downward trend with increasing falling height and moisture content, while it tends to rise as the material thickness increases. Data analysis and comparison reveal that, given the determination of the collision material, the moisture content of wheat exerts the most significant effect on the elastic recovery coefficient, followed by material thickness, while the influence of falling height is less pronounced. The findings of this study can provide data support for simulation testing and product design of wheat combine harvester cleaning screen body mechanisms and wheat seeders. [ABSTRACT FROM AUTHOR]

Perovskite materials are considered the gateway of various physical applications to meet the production and consumption of energy and medical fields. Density Functional Theory (DFT) becomes the most important field in the modern era to investigate perovskite materials for various physical properties. DFT nowadays is used to explore the perovskite materials for a lot of applications like photocatalytic, optoelectronic, and photovoltaics. We discussed radium based cubic hydrides RbRaX3 (while X = F & Cl) perovskite material's electrical, optical, elastic, & physical characteristics with the help of DFT-based CASTEP code with PBE exchange-correlation efficient of GGA. The RbRaF3 & RbRaCl3 have three-dimensional nature by means of space group 221 (Pm3 m). According to electronic characteristics, the direct bandgap of RbRaF3 RbRaCl3 are 3.18eV and 2.209eV, respectively. Both compounds are brittle in nature via Poisson's ratio & Pugh's criteria. Thus, our novel RbRaX3 (X = F and Cl) compounds have excellent applications for solar cell and medical areas.

The challenge of determining nine elastic characteristics of orthotropic woven composites is considered. Using a test example, the influence of transverse elastic characteristics on the results of the stress-strain state analysis of composite structures is assessed. To determine the transverse elastic constants of an orthotropic woven composite, we propose to use a representative volume of the materials repeated structure. The features of creating a finite element model of a representative volume of a layered woven composite are considered. To determine the elastic properties of an orthotropic woven composite, kinematic boundary conditions of a special type and calculation ratios are proposed that virtually simulate a mechanical experiment with a representative volume of material. The results of comparison of the calculated characteristics and field test data by standard methods are presented, which indicate the possibility of predicting transverse elastic characteristics by computational methods with a sufficiently high accuracy for use in practical tasks.

All-solid-state batteries (ASSBs) are the important attributes of the forthcoming technologies for electrochemical energy storage. A key element of ASSBs is the solid electrolyte materials. Garnets are considered promising candidates for solid electrolytes of ASSBs due to their chemical stability with Li metal anodes, reasonable kinetic characteristics (σLi∼ 10−3–10−4 S · cm−1) and a wide electrochemical window. This study is aimed at the analysis of the experimental data available for garnet thin films, examining the ionic conductivity through the film/substrate lattice mismatch, the elastic properties and the difference in the thermal expansion characteristics of the film and the substrate, the deposition temperature of the film, and the melting point and the dielectric constant of the substrate. Based on the results of this analysis and by introducing the corresponding characteristics involved as the descriptors, the quantitative models for predicting the ionic conductivity values were developed. Some important characteristic features for ion transport in garnet films, which are primarily concerned with the film/substrate misfit, elastic properties, deposition temperature, cation segregation and the space charge effects, are discussed.

Three models with different footing types were used to clarify the effect of heave plates on the hydrodynamic behavior of the elastic response of a flexible multicolumn floating offshore wind turbine (FOWT). The models were tested under regular waves, whose added mass, damping, and motion response results were compared with numerical simulations by NK-UTWind and WAMIT codes. As a whole, the attachment of heave plates was responsible for increasing the added mass and damping levels, consequently modifying the RAO of the models. Regarding the response in a sea condition, a decrease of 33% and 66% of the significant motion height (heave and pitch) was observed. Thus, the heave plate can be a good feature for the future design of FOWT. [ABSTRACT FROM AUTHOR]

This study investigates the elastic response characteristics of a floating wind turbine (FOWT) with two vertical-axis wind turbines (VAWTs), called double-rotor VAWTs. The model consists of two VAWTs mounted on a single semi-submersible floating structure and employs a single point mooring, which allows the FOWT to always self-align with the wind. Usually, a coupled analysis of the wind turbine and floating structure is used in the design of FOWTs; however, there is no coupled analysis available for VAWTs. In this study, we attempted to combine the wind turbine design software "QBlade" and the coupled wind turbine/floating body analysis code "UTWind" as one of the methods of coupled analysis of a VAWT and a floating body. Numerical simulation results were compared with experimental results using an elastic model scaled down to 1/100 of its actual model to determine the motion response and cross-sectional bending moments. The experimental results showed that the thrust of the VAWT had a particular influence on the cross-sectional forces and motion response between the two VAWTs. For cross-sectional forces, all results showed similar trends. Overall, the results of UTWind for double-rotor VAWTs are reasonable. It was also found that the pitch motion must be accurately reproduced to improve the accuracy. [ABSTRACT FROM AUTHOR]

Superdeep fault-karst carbonate reservoirs discovered over 7 km deep are controlled by strike-slip fault zones and karst collapses in Tarim Basin, Northwest China. The resulting fracture-cave system provides favorable migration channels and reservoir spaces for hydrocarbon, while the characterization of the internal fault structures remains enigmatic. Based on seismic imaging data, we conducted an integrated study on fault damage zones by seismic curvature attributes, velocity anisotropies, and seismic attenuations. The results show that three typical fault-zone patterns can be identified in the study area, including paratactic multiple fault cores, interactive fault cores and one primary-several subsidiary fault cores. These typical patterns can be clearly characterized via curvature attributes. The elastic characteristics of fault damage zones are significantly affected by seismic frequencies, which are manifested from velocity anisotropies and seismic attenuations. The maximum seismic attenuation occurs along with the orientation of fault cores. There is a strong anisotropic characteristic of P-wave phase velocity with incident angle of three fault-zone models. It appears that seismic attributes associated with geological steering are an effective tool for the subsurface characterization of fault damage zones. [ABSTRACT FROM AUTHOR]

Many of the engineering applications have faced the delicate contact problem in the area close to the forces where it is very difficult to experimentally carry out various measurements and draw important conclusions on the condition of the contact points. In this paper the forced state in the vicinity of the forces for the half-plane will be studied. Furthermore, the qualities displayed by the half-plane under the action of normal forces, tangential forces and the moment caused by a pair of forces will be analyzed, as well as changes in the elastic characteristics for the forced plane state and the deformed plane state. [ABSTRACT FROM AUTHOR]

To establish a collision model of wheat grains impacting a force plate with a piezoelectric sensor, and to investigate the influence of the elastic recovery coefficient on the sensor’s detection accuracy during the collision process, this study employed object kinematic principles to construct a wheat elastic recovery coefficient measurement device. This device ascertains the elastic properties of wheat during collisions and determines the elastic recovery coefficient of the wheat collision model. The wheat variety Jinan No. 17 was selected for testing, and the effects of the contact material, grain drop height, material thickness, and grain moisture content on the collision recovery coefficient during the collision process were analyzed through single-factor and multi-factor experiments. The experimental results demonstrate that the collision recovery coefficient of wheat grains increases with the stiffness of the collision materials for different materials. The grain recovery coefficient of wheat exhibits a downward trend with increasing falling height and moisture content, while it tends to rise as the material thickness increases. Data analysis and comparison reveal that, given the determination of the collision material, the moisture content of wheat exerts the most significant effect on the elastic recovery coefficient, followed by material thickness, while the influence of falling height is less pronounced. The findings of this study can provide data support for simulation testing and product design of wheat combine harvester cleaning screen body mechanisms and wheat seeders.

The effect of short carbon fiber (SCF) filler on the mechanical properties of 3D-printed acrylonitrile butadiene styrene (ABS) was investigated. The fused filament fabrication (FFF) method was used for the manufacturing of samples. Elastic properties and strength characteristics of samples made of conventional ABS and SCF-reinforced ABS were compared in tensile and bending tests. Fracture toughness and critical strain energy release rate were also determined. In addition, 3D-printed monofilament SCF-reinforced samples were fabricated, the internal structure of which was analyzed using microcomputed tomography (micro-CT). Based on the tomography data, finite-element (FE) models of representative volume elements (RVEs) of the reinforced material were created and used for the numerical calculation of effective characteristics. Numerical and experimental results for the effective elastic properties were compared with the Mori-Tanaka homogenization technique. The ABS samples filled with SCF showed considerably higher mechanical characteristics than those of the conventional ABS. Finally, the dependence between the strength characteristics and elastic properties of the samples on the diameter of the nozzle used for 3D printing was established. 3D-printed ABS reinforced with SCF demonstrated a gain in tensile strength and fracture toughness by 30% and 20%, respectively. Interlayer adhesion strength in flexure tests showed an increase of 28% compared to pure ABS samples.

Three models with different footing types were used to clarify the effect of heave plates on the hydrodynamic behavior of the elastic response of a flexible multicolumn floating offshore wind turbine (FOWT). The models were tested under regular waves, whose added mass, damping, and motion response results were compared with numerical simulations by NK-UTWind and WAMIT codes. As a whole, the attachment of heave plates was responsible for increasing the added mass and damping levels, consequently modifying the RAO of the models. Regarding the response in a sea condition, a decrease of 33% and 66% of the significant motion height (heave and pitch) was observed. Thus, the heave plate can be a good feature for the future design of FOWT.

This study investigates the elastic response characteristics of a floating wind turbine (FOWT) with two vertical-axis wind turbines (VAWTs), called double-rotor VAWTs. The model consists of two VAWTs mounted on a single semi-submersible floating structure and employs a single point mooring, which allows the FOWT to always self-align with the wind. Usually, a coupled analysis of the wind turbine and floating structure is used in the design of FOWTs; however, there is no coupled analysis available for VAWTs. In this study, we attempted to combine the wind turbine design software “QBlade” and the coupled wind turbine/floating body analysis code “UTWind” as one of the methods of coupled analysis of a VAWT and a floating body. Numerical simulation results were compared with experimental results using an elastic model scaled down to 1/100 of its actual model to determine the motion response and cross-sectional bending moments. The experimental results showed that the thrust of the VAWT had a particular influence on the cross-sectional forces and motion response between the two VAWTs. For cross-sectional forces, all results showed similar trends. Overall, the results of UTWind for double-rotor VAWTs are reasonable. It was also found that the pitch motion must be accurately reproduced to improve the accuracy.

Crack micro-geometries and tribological properties have a significant influence on the elastic characteristics of naturally fractured reservoirs. Numerical simulation as a promising approach for this issue still faces some challenges. For this purpose, we develop an integrated numerical scheme accounting for roughness effects by coupling a modified lattice spring model (LSM) with discrete fracture networks (DFNs). Complex fracture networks presented by DFNs are automatically extracted based on the gradient Hough transform algorithm (GrdHT). Smooth joint logic (SJL) is employed to avoid the artificial roughness effect from numerical discretization. Improved constitutive laws are also implemented in the modified LSM to calculate the realistic normal force-displacement from rough contact deformation. We validate this presented framework through theoretical solutions. It shows the potential for reconstructing actual structural attributes and quantitatively investigating the fracture attributes and microscale surface roughness effects on elastic characteristics. [ABSTRACT FROM AUTHOR]

Single-walled carbon nanotubes (SWCNT) are a seamless cylindrical structure formed by folding a single-walled graphene sheet. Nanotubes are of great interest due to their unique thermo-mechanical characteristics. Such objects can be applied in the energy, rocket and aerospace engineering as a filler of advanced structural composite materials.One of the most important SWCNT characteristics is a complex of its elastic properties. The most reliable way to determine the elastic characteristics of a nanotube is to conduct an experiment. However, due to high cost and lengthy time of the experiment completion, it is more preferable to use mathematical modeling of these properties of SWCNT with which the paper deals.The paper proposes a mathematical model that is constructed by methods of generalized continuum mechanics. To use these methods, the nanotube, on the assumption of its transverse isotropy, is presented simultaneously as a cylindrical shell and a continuous circular rod.As a result of consideration of various stress-strain states of the shell and rod, are obtained relations to establish a quantitative relation between the elements of the matrix of compliance coefficients of a rod that simulates a single-walled carbon nanotube, and the elastic characteristics of graphene taken as its basis in the isotropy plane. Also, the constructed mathematical model allows us to define the influence of the nanotube configuration (chiral indices) on its elastic characteristics.The paper presents the application results of the model proposed, using as an example, a SWCNT with chirality indices (7, 0), for which were constructed mutually inverse matrices of compliance and elasticity coefficients that completely describe the elastic properties of the nanotube.Using the proposed mathematical model significantly reduces the time and cost for estimation of the elastic characteristics of the SWCNT, that is especially important at the design stage of new materials based on them.

The resistance of adhesive joints of rubbers in various climatic zones (Yakutsk, Moscow, Zvenigorod, Murmansk, Gelendzhik, Batumi) glued together and with metals using VKR-24, VKR-27, VKR-60, VKR-61, VKR-85, VKR-90, and VKR-95 glues is studied. It is shown that glues for industrial rubber articles have different resistances, which depends on the raw rubber used in the composition of the adhesive, the gluing temperature, and the type of glued materials. [ABSTRACT FROM AUTHOR]

This study is an attempt to investigate possible applications of rubber granulate SBR (styrene-butadiene rubber) produced from recycled waste tires as an elastic cover for prototype rail dampers, which are aimed at reducing the level of railway noise emitted in the environment. The authors present laboratory procedures and discuss the results of several experimental tests performed on seven different SBR materials with the following densities: 1100, 1050, 1000, 850, 750, 700 and 650 kg/m3. It is proven that rubber granulate SBR produced from recycled waste tires, can be used as an elastic cover in steel inserts in rail dampers, provided that the material density is not lower than 1000 kg/m3. In the conducted tests, samples of the materials with high densities exhibited good static and dynamic elastic characteristics and had sufficient operational durability.

Composite materials are widely used in engineering, especially in constructions working under simultaneous intensive mechanical and thermal loads. In the industry the main requirements for materials are restrictions on the elastic characteristics, such as bulk modulus and shear modulus.Composite materials consist of a base material, a so-called binder (matrix), and reinforcing inclusions. The composite matrix defines a method for the composite manufacturing and must meet a set of operational and technological requirements. The most commonly used types are a metal matrix and a polymer one, because of the relative ease of manufacture, good wettability, and chemical resistance.Reinforcing inclusions can be of different nature (boron, crystalline, etc.) and shape (spherical, lamellar, fiber). Lately, active researches have been conducted with the nanostructural elements (fullerenes, single-walled and multi-walled carbon nanotubes (SWCNTs and MWCNTs) plates, nanoclusters) used as the filler.There are various ways of modeling the elastic properties of the composites. The most common are numerical methods using a finite element method and analytical methods.In simulation of composite characteristics, in addition to the properties of its components, a reinforcing structure plays an important role.The paper considers an obtained isotropic composite with a metal matrix reinforced by the spherical nanoclusters of randomly oriented SWNTs with a reinforcement scheme similar to the cubic crystal lattice. Numerical modeling and analytical methods were used.For the numerical solution two types of periodic structure of the material were obtained: a cube with eight parts of the ball in the corners of a cube and a sphere in the center. For each of the periodic cells a representative volume is selected in which, using the kinematic and force boundary conditions, have been implemented two types of stress-strain state, namely stretching along one axis and shear. For numerical implementation was used a ANSYS software complex coupled with a specially designed software module that allows creating tensors of elastic coefficient and pliability of the composite, as well as averaging its elastic characteristics to have values of bulk and shear moduli of the material.The results of numerical simulations have been compared with the analytical estimates obtained by the self-consistent method and the dual formulation of the elasticity problem in a heterogeneous solid. It is found that in numerical implementation a choice of the composite periodic cell has a significant impact on the values of the shear modulus as opposed to the bulk modulus of elasticity. It is also shown that the numerical simulation results are between the estimates obtained using the analytical models. These results allow predicting the elastic properties of composites, reinforced by spherical inclusions, including advanced materials, i.e. nanocomposites reinforced by spherical nanoclusters of randomly oriented SWCNTs.The paper is done within the framework of implementing basic part of the Governmental task of the Ministry of Education and Science of the Russian Federation (Project 9.7784.2017/БЧ).

In this paper the details about manufacturing of multilayer cylinders consisting of metal liner (obtained by standard machining procedures) and polymeric composite material (produced by filament winding technology) are presented. For multilayer cylinders manufacturing three types of steel liner (each liner type has three different wall thicknesses) are used. Glass fibers impregnated with polyester resin were wound at the outer surface of the mentioned nine liners and so the manufactured multilayer tubes were exposed to the action of internal hydraulic pressure with measurement of deformations in radial direction. Two groups of the results, obtained during hydraulic testing of multilayer cylinders, were presented: one group represents elastic characteristics, i.e. the properties of the examined tubes at the elastic limit, and another group represents the final properties, i.e. the characteristics of the tested tubes at the moment of burst. Calculation of the pressure at the elastic limit, by a simplified procedure, was done. By comparing the value of experimentally tested pressure at the elastic limit and the value of calculated pressure at the elastic limit, it was concluded that there is a good agreement between these two data. Values of experimentally tested radial deformations at the elastic limit of external surface of multilayer tubes and values of this parameter obtained by calculation of simplified model, are, also, meaningfully approximate. Based on the experimental data, an influence of a pathway from the lower outside liner diameter to higher outside liner diameter was established, and, also, an influence of liner wall thickness on characteristics of multilayer tubes, which were exposed to the action of internal hydraulic pressure. Based on the introduced parameter hydraulic burst pressure/mass ratio, it was concluded that a higher presence of polymer composite material has positive influence on hydraulic burst pressure (increasing) and mass (decreasing) of the mentioned multilayer tubes.

Graphical abstract Abstract A method of fabricating thin-film diaphragms of cellulose nanofiber (CNF) for the application of displacement membranes of MEMS actuators or microfluidic devices was developed and the mechanical characteristics were evaluated. CNF has high strength and elastic modulus; however, it is necessary to provide flexibility for the use as a displacement membrane. A polar solvent, tertiary-butyl alcohol (tBA), at a high concentration of approximately 66 vol%, was used to thin the CNF film, that is, to reduce the aggregation and viscosity of the CNF. The CNF films fabricated by this method were of approximately 4-μm thickness. The fabricated films had a good gas barrier property and had an isotropic Young's modulus. An evaporation layer of aluminum (approximately t0.3 μm) was deposited on the surface of the CNF film as a shield layer for water repellency. The displacement characteristics of the diaphragm of the film (t4 μm) were measured in the actuators using air pressure or a magnetic field and they were close to those of a polyimide thin film of thickness 7.5 μm. The dynamic reproducibility and resilience of the displacement were ensured. The proposed method could easily form CNF films of thickness down to several micrometers and the fabricated films could be used as displacement membranes for gases and liquids. [ABSTRACT FROM AUTHOR]

A tank experiment using a flexible multi-column floating offshore wind turbine (FOWT) model in regular waves was carried out to clarify the floater elastic response and its influence on the floater motion. The model motion response from the experiment was compared with the numerical simulations by NK-UTWind and WAMIT codes. The dynamic elastic deformation of the model was also compared between the experiment and NK-UTWind. The experiment observed significant elastic deformation for the decks and columns of the model around the wave period corresponding to the natural period of the structural vibration. Furthermore, comparing the heave response amplitude operator (RAO) between experiments and numerical simulations, a small peak appeared around this period in the experiment and NK-UTWind simulation instead of WAMIT simulation. These results indicated that dynamic elastic deformation affected the heave response of the model. The change in the model rigidity revealed that such elastic deformation could affect the motion response statistics in an actual sea condition if the peak period of the onsite wave spectrum is close to the floater natural vibration period. These investigations indicated the importance of considering the elastic behavior of a FOWT at its design stage.

A shallow draft cylindrical barge type floater with footing close to the water surface was experimentally evaluated in waves to investigate non-linear motion characteristics. The floater was designed to be used as an option for FOWT—floating offshore wind turbines. The non-linear mechanism can be promoted due to the viscous force that acts on the footing edges and the footing interaction with the free surface. In general, the observed non-linear viscous damping is modeled as a force proportional to the square of the relative velocity between the floater and the water. Therefore, the viscous damping levels is expected to increase, and the response in waves, to decrease. However, an increase in motion responses was observed for a broad range of wave periods. An attempt was made to clarify the hydrodynamic mechanism by comparing wave tank experiments, numerical calculations by CFD—computational fluid dynamics codes, and linear potential theory codes. Regular wave tests for three different wave height conditions were carried out, including free decay tests in still waters. For CFD simulations, the OpenFOAM code was selected. For potential theory simulations, the WAMIT code was chosen. As a result of the research, three points could be highlighted and discussed: first, the hydrodynamic phenomenon that contributed to the non-linear motion of the floater was identified; second, the increase and coupling of the motions response of heave and pitch motions; and finally, the phenomenon that the footing held water mass and lifted it to the water surface. The CFD calculations were able to get good qualitative results compared with the experiments and confirmed the use of CFD as a useful tool to capture the non-linear hydrodynamic phenomenon. The linear potential theory was not able to capture the phenomenon discussed herein.

A floating offshore wind turbine (FOWT) concept with a guy-wire-supported tower was investigated to obtain motion results in waves considering its elastic model characteristics. The FOWT concept studied aims to reduce the construction costs by using a light-weight structure tensioned with guy wires and a downwind type. Wave tank experiments of an elastically similar segmented backbone model in the 1:60 scale were carried out to clarify the dynamic elastic response features of the structure. The experimental results were compared with numerical simulations obtained from NK-UTWind and WAMIT codes. The bending moment measured at the tower and pontoons had two peak values for different wave periods carried out. The short-wave period peak was due to sagging/hogging when the wavelength matched the floater length. The second peak was due to the large tower top acceleration, which caused a large bending moment at the tower base and pontoon to support the inertia force. The wind force was not significant to modify the FOWT response. The sensibility analysis in pontoons and tower rigidities confirmed the importance of the guy wires to support the inertia due to the waves and wind incidence. The new concept of a very-light FOWT with a guy-wire-supported tower may be an option for future FOWT developments.

Analytical formulas are derived and an analysis of sensitivity of angle-ply composite structures to deviations of their elastic characteristics is performed. It is shown that the properties of the structures are determined mainly by their degree of anisotropy - the ratio of the longitudinal elastic modulus of a unidirectional material to its transverse one. For the basic classes of composites (high-, medium-, and low-modulus carbon-fiber, organo-, and glass-fiber plastics), recommendations for a rational choice of their structures to obtain experimental results allowing one to identify the elastic characteristics of unidirectional composites are formulated. [ABSTRACT FROM AUTHOR]

The effect of low-cycle fatigue on the elastic and acoustic characteristics of austenitic stainless steel AISI 321 is investigated. The relation between characteristics of the hysteresis loop and changes of the acoustic parameters is established. A change of the elastic characteristics of austenitic stainless steel associated primarily with martensitic transformations that affect cyclic hardening, the width of the hysteresis loop, energy loss in the cycle, and the accumulated energy density is found. The influence of the amplitude of strain cycle on development of the elastic anisotropy is analyzed. The relationship between changes of elastic characteristics and damage is suggested; it can be used for evaluation of fatigue life by the acoustic method. [ABSTRACT FROM AUTHOR]

Scope composites as structural materials sensing mechanical stresses are largely determined by a complex of their elastic properties. Described in the article of review papers devoted to the elastic properties of the composite, it follows that the problem of theoretical evaluation of these characteristics, remains relevant. When considering composites reinforced with spherical inclusions, most famous works of the composite matrix and the inclusion is considered to be isotropic. However, for use as inclusions of metal particles and nanostructured elements often need to consider the anisotropy of the elastic characteristics.In the article for a composite with anisotropic spherical inclusions built two types of estimates of values of the bulk modulus and shear modulus . As background information used elastic properties of the matrix and the inclusions and their content by volume in the composite.The first type is classified as two-sided estimates of desired values that are based on the dual variational formulation of the linear elasticity problem of an inhomogeneous solid body containing alternative functionals (Lagrange and Castigliano). These functionals on the true distribution of strains and stresses in an inhomogeneous body reach the same meaning extremes (minimum and maximum respectively). On the convergence of the distribution of the Lagrange functional application allows you to get an upper bound of desired values, and the use of functional Castigliano - their lower bound.The second type of assessment is built by self-consistency, this method allows for the interaction of a single particle on or matrix composite with a homogeneous isotropic medium having measured the elastic moduli. Averaging over the volume of the composite disturbances arising strains and stresses in the inclusions and matrix particles makes it possible to obtain the calculated dependences for the bulk modulus and shear modulus of the composite. Comparison of these calculations for these dependences with relevant bilateral estimates not only allows you to set the degree of reliability of the results, but also to quantify their possible error.

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Perovskite materials are considered the gateway of various physical applications to meet the production and consumption of energy and medical fields. Density Functional Theory (DFT) becomes the most important field in the modern era to investigate perovskite materials for various physical properties. DFT nowadays is used to explore the perovskite materials for a lot of applications like photocatalytic, optoelectronic, and photovoltaics. We discussed radium based cubic hydrides RbRaX 3 (while X = F & Cl) perovskite material's electrical, optical, elastic, & physical characteristics with the help of DFT-based CASTEP code with PBE exchange-correlation efficient of GGA. The RbRaF 3 & RbRaCl 3 have three-dimensional nature by means of space group 221 (Pm3 m). According to electronic characteristics, the direct bandgap of RbRaF 3 RbRaCl 3 are 3.18eV and 2.209eV, respectively. Both compounds are brittle in nature via Poisson's ratio & Pugh's criteria. Thus, our novel RbRaX 3 (X = F and Cl) compounds have excellent applications for solar cell and medical areas., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

Results of experimental room-temperature studies on the deformation and strength of UOL-300-1A and UT-900-3A carbon cloth-reinforced plastics and laminar composites on their basis are presented. All elastic and strength characteristics of the materials are evaluated at the plane stress state. Evaluation lines for elastic and strength characteristics of laminar carbon cloth-reinforced composites are investigated. The prediction efficiency for elastic characteristics of laminar woven composites is analyzed on the basis of corresponding parameters of a single layer. [ABSTRACT FROM AUTHOR]

Semi-empirical relation was used to predict bulk modulus of defective perovskites A 2 BX 6 cubic crystals. [Display omitted] • Semi-empirical relation was used to predict bulk modulus of defective perovskites. • This relation relates lattice constant and product of ionic charges. • The linear regression is used to relate lattice constant and product of ionic charges with bulk modulus. • The calculated bulk moduli differ at average of 3% from available values in literature. In this work, a semi-empirical relation was elaborated in terms of lattice constant (a ∘) and product of ionic charges (Z a Z b Z x) for the calculation of bulk moduli (in GPa) of A 2 BX 6 (A: large cation, B: transition metal and X: halide anions) structured materials. Z a Z b Z x and a ∘ were related through bulk moduli through linear regression. These two parameters yield a straight regression line, when plotted but fall on different positions due the variation in bulk moduli values. The calculated values of bulk moduli (reflecting elastic characteristics) are in close agreement with the other available values. As, these values are only differing by average of 3% from values in the literature. Moreover, the regression resulted in good values of correlation coefficient (R = 0.77) and Probability (P = 0.001). These all show the accuracy and reliability of the current work. The technique adopted in this work will be helpful to material scientists for finding new materials with preferred elastic characteristics among structurally similar materials, also the calculated data will act as a reference for upcoming investigation of the studied compounds. [ABSTRACT FROM AUTHOR]

The calibration of the elastic characteristics of deformed coals is essential for seismic inversion of such units, because the prediction of coal deformation is essential for both mining safety and methane production. Therefore, many samples of broken and mylonitic deformed coal were tested with ultrasonic waves in the laboratory. These samples came from four mining areas: the Huainan, Pingdingshan, Hebi and Jiaozuo coal mines, which present five different metamorphic ranks shown as cylinders striking across circular limits of steel. Under normal pressures and temperatures, ultrasonic P- and S-wave tests show that the velocities, quality factors, and elastic moduli of the deformed coals were greatly reduced compared with undeformed coals. Also, some correlation was found between the P- and S-wave velocities in the deformed coals. However, there is no evidence of linear correlations between velocity and density, velocity and quality factor, or the quality factors of P- and S-waves. Compared with the elastic characteristics of undeformed coals, such as P- and S-wave velocity ratios or Poisson's ratio, those of deformed coals generally decrease and the P-wave quality factors are less than those of S-waves. Moreover, the analysis of the relationship between pore structure and elastic modulus shows a better correlation between the P- and S-wave velocities and effective porosity, pore volume and specific surface area. Also, there are similar relationships between the pore structure and the Young's and shear moduli. However, there are no such correlations with other moduli. Correlations between these elastic moduli, pore structure, coal rank and density were not found for the various samples of deformed coals, which is consistent with only structural destruction occurring in the deformed coals with other physical properties remaining unchanged. The experimental results show that it is possible to predict the deformation of coals with multi-component seismic elastic inversion. [ABSTRACT FROM AUTHOR]

In the continuous shifting condition, frequent working on a dry clutch causes a sharp internal temperature rise on the friction surfaces of the clutch. In order to determine the force on the friction surfaces of the clutch accurately, the elastic characteristics produced by the cushion spring, the link strip and the diaphragm spring are analysed in this paper. Then, through monitoring of the throw-out bearing force, the friction torque of the clutch and the slipping-friction power can be estimated. Finally, based on three thermal loads on the friction surfaces of the dry clutch (including the initial environment temperature, the slipping-friction power and the convection heat), its thermal field distribution with changes in the time and the radius during the entire shift process can be acquired. In the earlier phase (before approximately 180 s), the surface temperature distribution varies with the slipping-friction power. Also the slipping-friction power plays a major role in the thermal load on the friction surfaces. However, the slipping-friction power does not do so in the later phase (after about 180 s) owing to the difficulty with heat radiation. This means that the time-varying thermal characteristics of a dry clutch are related to the working time of the clutch. [ABSTRACT FROM AUTHOR]

Abstract: An alternative floor field (FF) model is proposed by incorporating the agitated behavior and elastic characteristics of pedestrians. The agitated behavior which is regarded as an important factor to pedestrian dynamics is depicted by introducing a parameter to revise the transition probability of pedestrians to move to the neighboring cells. To characterize elasticity of pedestrians, it is assumed that a cell can hold more than one pedestrians in crowd condition, while it can hold only one pedestrian in normal condition. In addition, a method to deal with conflicts is employed by considering the effects of agitated behavior and desired velocity. Numerical simulations are carried out to investigate pedestrian evacuation from a room. The results show, that as the value of agitated parameter increases, the evacuation time decreases to the minimum value and then increases gradually. Also, the faster-is-slower effect which is obtained by some other simulation models can be reproduced by the proposed model. Finally, the influence of exit width and the corresponding mechanism on evacuation process is investigated which is expected to be helpful to the exit design of public rooms. [Copyright &y& Elsevier]

The paper summarizes the results of assessment of geo mechanical characteristics of magmatic rock samples collected from the Mures corridor: Pietroasa, Brănisca, Zam, Căzăneşti and Săvârşin. Because rocks can be used in construction it is necessary that they satisfy certain quality conditions. The rock characteristics significantly are influenced by climate factors, in particular temperature and humidity. In this respect, the paper deals with the physical, mechanical elastic tubes and technology on the rocks dry, saturated, and subjected to 25-50 cycles of freeze-thaw. Coefficients were determined by soaking, gelivity and values obtained were compared with those required by standards. The values obtained for the geo mechanical characteristics of rocks were compared with the conditions of admissibility imposed by standards. [ABSTRACT FROM AUTHOR]

The paper presents a brief analysis of the amplitude-frequency characteristics at a variable frequency of vibration excitation in a specimen and constant temperature and at a constant frequency of vibration excitation and variable temperature. The error of determination of the elastic and inelastic characteristics of high-damping materials is estimated by the resonance methods. [ABSTRACT FROM AUTHOR]

The mechanical behavior of multilayer satin-weave glass fabric-reinforced plastics under elastic deformation is investigated. Different experimental procedures for determining elastic characteristics of composite materials are analyzed. The effect of material cooling down to 77 K on its mechanical behavior is examined. [ABSTRACT FROM AUTHOR]

The static and dynamic characteristics of the rubber mounts for vibration isolation in automotive powertrains and other dynamic systems should be predicted during their design and development stage. In this paper, the static characteristic simulation of a rubber mount is performed using the finite element method. The modelling and simulation methods for a large deformation rubber spring represented by axisymmetric, quarter-symmetric and three-dimensional finite element models are investigated by using finite element analysis software PATRAN for meshing and ABAQUS and ADINA for computations. The predicted vertical static elastic characteristics of the rubber spring agree well with the experimental results. The static strain–stress analysis of the rubber part shows that the von Mises stress can be adopted as a stress measure for the rubber material. Moreover, the modelling methods for the large deformation rubber mount are investigated with numerical tests of elastic characteristics. The hybrid elements with full integration and lower-order interpolation show less distortion and are suitable for large deformation simulation computations. The research results will help engineers and researchers to perform engineering design and analysis of rubber mounts and other vibration reduction rubber components using the finite element simulation method. [ABSTRACT FROM AUTHOR]

Muscles have variable dynamic characteristics changing the mechanical impedance in response to an exerted force. In order to clarify elastic characteristics of the muscles, an experiment of tracking a ramp shape with an external elastic load was conducted, and harmonic oscillations in tracking error angles were analyzed over time using the wavelet transform method. The time variable spectra of the error angles are constructed from two distributions with 5 Hz as their border. It was found that the frequencies of the high band distribution tended to increase as the load elasticity coefficient increased. The frequency trends were described using two musculodynamic models (the parallel elastic model and the coupled oscillation model) and the muscular elastic characteristics were estimated from these models. The results showed that the coupled oscillation model agreed with the experimental values, as compared with the traditional parallel elastic model. In addition, it was suggested that the elastic characteristics of the muscles were related to the sports activity experiences. © 2000 Scripta Technica, Syst Comp Jpn, 31(13): 76–86, 2000 [ABSTRACT FROM AUTHOR]