Статті в журналах з теми "Shear modulu"
Щоб переглянути інші типи публікацій з цієї теми, перейдіть за посиланням: Shear modulu.
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся з топ-50 статей у журналах для дослідження на тему "Shear modulu".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Переглядайте статті в журналах для різних дисциплін та оформлюйте правильно вашу бібліографію.
1
Yoshihara, Hiroshi, Momoka Wakahara, Masahiro Yoshinobu, and Makoto Maruta. "Torsional Vibration Tests of Extruded Polystyrene with Improved Accuracy in Determining the Shear Modulus." Polymers 14, no. 6 (March 13, 2022): 1148. http://dx.doi.org/10.3390/polym14061148.
Повний текст джерелаАнотація:
Recently, extruded polystyrene (XPS) foam has been used as a component of construction materials; therefore, it is important to characterize its mechanical properties, including shear modulus. Despite the importance, it is often difficult to determine the shear modulus accurately by using many of the conventional methods; therefore, it is desirable to establish another method to measure the shear modulus with a high accuracy. Among various methods, torsional vibration test is advantageous because it can be performed easily under the pure shear stress condition in the test sample and both the in-plane and out-of-plane shear moduli can be obtained. However, it is difficult to find any examples performing the torsional vibration tests. In this study, the in-plane and out-of-plane shear moduli of XPS were determined through torsional vibration tests using samples of various widths. In addition, the shear moduli were also determined through flexural vibration tests and compared with those obtained from the torsional vibration tests. In the torsional vibration tests, the anisotropy in these shear moduli became an obstacle, and the in-plane shear modulus determined using a single sample was often dependent on the width/thickness ratio of the sample. In this condition, the coefficient of variation of the in-plane shear modulus value was often close to 10%. However, when using data obtained from the samples with various width/thickness ratios, both the in-plane and out-of-plane shear moduli could be obtained while reducing the abovementioned dependence. Additionally, the coefficients of variation were restricted to those below 2% and 7% for the in-plane and out-of-plane shear moduli, respectively, and these values were obviously lower than those obtained from the flexural vibration tests (approximately 20%). In the proposed method, both the in-plane and out-of-plane shear moduli can be obtained accurately without using any numerical analyses, which are often required in the standardized methods to improve the accuracy. Thus, for accurate measurement of both types of shear moduli of XPS, we recommend performing torsional vibration tests using a range of samples of various width/thickness ratios.
2
Omovie, Sheyore John, and John P. Castagna. "Relationships between Dynamic Elastic Moduli in Shale Reservoirs." Energies 13, no. 22 (November 17, 2020): 6001. http://dx.doi.org/10.3390/en13226001.
Повний текст джерелаАнотація:
Sonic log compressional and shear-wave velocities combined with logged bulk density can be used to calculate dynamic elastic moduli in organic shale reservoirs. We use linear multivariate regression to investigate modulus prediction when shear-wave velocities are not available in seven unconventional shale reservoirs. Using only P-wave modulus derived from logged compressional-wave velocity and density as a predictor of dynamic shear modulus in a single bivariate regression equation for all seven shale reservoirs results in prediction standard error of less than 1 GPa. By incorporating compositional variables in addition to P-wave modulus in the regression, the prediction standard error is reduced to less than 0.8 GPa with a single equation for all formations. Relationships between formation bulk and shear moduli are less well defined. Regressing against formation composition only, we find the two most important variables in predicting average formation moduli to be fractional volume of organic matter and volume of clay in that order. While average formation bulk modulus is found to be linearly related to volume fraction of total organic carbon, shear modulus is better predicted using the square of the volume fraction of total organic carbon. Both Young’s modulus and Poisson’s ratio decrease with increasing TOC while increasing clay volume decreases Young’s modulus and increases Poisson’s ratio.
3
Berryman, James G. "Fluid effects on shear waves in finely layered porous media." GEOPHYSICS 70, no. 2 (March 2005): N1—N15. http://dx.doi.org/10.1190/1.1897034.
Повний текст джерелаАнотація:
Although there are five effective shear moduli for any layered transversely isotropic with a vertical symmetry axis (VTI) medium, one and only one effective shear modulus of the layered system (namely, the uniaxial shear) contains all the dependence of pore fluids on the elastic or poroelastic constants that can be observed in vertically polarized shear waves. Pore fluids can increase the magnitude of shear energy stored in this modulus by an amount that ranges from the smallest to the largest effective shear moduli of the VTI system. But since there are five shear moduli in play, the overall increase in shear energy due to fluids is reduced by a factor of about five in general. We can, therefore, give definite bounds on the maximum increase of overall shear modulus — about 20% of the allowed range as liquid is fully substituted for gas. An attendant increase of density (depending on porosity and fluid density) by approximately 5–10% decreases the shear-wave speed and thereby partially offsets the effect of this shear modulus increase. The final result is an increase of shear-wave speed on the order of 5–10%. This increase is shown to be possible under most favorable circumstances, that is, when the shear modulus fluctuations are large (resulting in strong anisotropy) and the medium behaves in an undrained fashion due to fluid trapping. At frequencies higher than seismic (such as sonic and ultrasonic waves for well logging or laboratory experiments), resulting short response times also produce the requisite undrained behavior; therefore, fluids also affect shear waves at high frequencies by increasing rigidity.
4
Lai-Fook, Stephen J., and Robert E. Hyatt. "Effects of age on elastic moduli of human lungs." Journal of Applied Physiology 89, no. 1 (July 1, 2000): 163–68. http://dx.doi.org/10.1152/jappl.2000.89.1.163.
Повний текст джерелаАнотація:
The model of the lung as an elastic continuum undergoing small distortions from a uniformly inflated state has been used to describe many lung deformation problems. Lung stress-strain material properties needed for this model are described by two elastic moduli: the bulk modulus, which describes a uniform inflation, and the shear modulus, which describes an isovolume deformation. In this study we measured the bulk modulus and shear modulus of human lungs obtained at autopsy at several fixed transpulmonary pressures (Ptp). The bulk modulus was obtained from small pressure-volume perturbations on different points of the deflation pressure-volume curve. The shear modulus was obtained from indentation tests on the lung surface. The results indicated that, at a constant Ptp, both bulk and shear moduli increased with age, and the increase was greater at higher Ptp values. The micromechanical basis for these changes remains to be elucidated.
5
Sinha, Bikash K., Badarinadh Vissapragada, Lasse Renlie, and Sveinung Tysse. "Radial profiling of the three formation shear moduli and its application to well completions." GEOPHYSICS 71, no. 6 (November 2006): E65—E77. http://dx.doi.org/10.1190/1.2335879.
Повний текст джерелаАнотація:
Near-wellbore alteration in shear stiffnesses in the three orthogonal planes can be described in terms of radial variations of the three shear moduli or slownesses. The three shear moduli are different in formations exhibiting orthorhombic or lower degree of symmetry, as is the case in deviated wellbores in triaxially stressed formations. These shear moduli are affected by factors such as overbalanced drilling, borehole stress concentrations, shale swelling, near-wellbore mechanical damage, and supercharging of permeable formations. The two vertical shear moduli [Formula: see text] and [Formula: see text] in an anisotropic formation with a vertical [Formula: see text]-axis are obtained from crossed-dipole sonic data, whereas the horizontal shear modulus [Formula: see text] is estimated from borehole Stoneley data. The effective shear modulus [Formula: see text] is smaller than the vertical shear moduli [Formula: see text] or [Formula: see text] in a poroelastic formation exhibiting high horizontal fluid mobility. Consequently, analyses of radial profiling of the three shear moduli in a reasonably uniform lithology interval yield useful correlations, with mobility impaired by an increased amount of clay or by near-wellbore damage in a shaley sand reservoir interval in a North Sea vertical well. Radial profiling results help to identify suitable depths for fluid sampling and to complete a well for optimum production.
6
Stamenovic, D., and J. C. Smith. "Surface forces in lungs. III. Alveolar surface tension and elastic properties of lung parenchyma." Journal of Applied Physiology 60, no. 4 (April 1, 1986): 1358–62. http://dx.doi.org/10.1152/jappl.1986.60.4.1358.
Повний текст джерелаАнотація:
The bulk modulus and the shear modulus describe the capacity of material to resist a change in volume and a change of shape, respectively. The values of these elastic coefficients for air-filled lung parenchyma suggest that there is a qualitative difference between the mechanisms by which the parenchyma resists expansion and shear deformation; the bulk modulus changes roughly exponentially with the transpulmonary pressure, whereas the shear modulus is nearly a constant fraction of the transpulmonary pressure for a wide range of volumes. The bulk modulus is approximately 6.5 times as large as the shear modulus. In recent microstructural modeling of lung parenchyma, these mechanisms have been pictured as being similar to the mechanisms by which an open cell liquid foam resists deformations. In this paper, we report values for the bulk moduli and the shear moduli of normal air-filled rabbit lungs and of air-filled lungs in which alveolar surface tension is maintained constant at 16 dyn/cm. Elevating surface tension above normal physiological values causes the bulk modulus to decrease and the shear modulus to increase. Furthermore, the bulk modulus is found to be sensitive to a dependence of surface tension on surface area, but the shear modulus is not. These results agree qualitatively with the predictions of the model, but there are quantitative differences between the data and the model.
7
Kennedy, J. G., D. R. Carter, and W. E. Caler. "Long Bone Torsion: II. A Combined Experimental and Computational Method for Determining an Effective Shear Modulus." Journal of Biomechanical Engineering 107, no. 2 (May 1, 1985): 189–91. http://dx.doi.org/10.1115/1.3138540.
Повний текст джерелаАнотація:
A technique is established which allows an effective torsional shear modulus to be determined for long bones, while remaining nondestructive to whole bone specimens. Strain gages are bonded to the diaphysis of the bone. Strains are then recorded under pure torsional loads. Theoretical stress predictions are combined with experimental strain recordings to arrive at a modulus value. Shear modulus calculations for four canine radii are reported using theoretical stress predictions from circular, elliptical and finite element models of the transverse bone geometry. The effective shear modulus, obtained from an average of the shear moduli determined at strain gage locations, serves to average the heterogeneous shear modulus distribution over the cross section. The shear modulus obtained is that associated with the “circumferential” direction in transverse planes.
8
Matseevich, T. A., A. A. Askadskii, M. D. Petunova, O. V. Kovriga, and M. N. Popova. "A Calculation Scheme for Assessing Storage Moduli and Losses as a Function of Polymer Chemical Structure and Blend Composition." International Polymer Science and Technology 45, no. 2 (February 2018): 53–57. http://dx.doi.org/10.1177/0307174x1804500205.
Повний текст джерелаАнотація:
A calculation scheme is proposed for assessing and predicting storage and loss moduli. The examination is based on atomic constants, which take into account the contribution of each atom and polar group and the van der Waals volume and shear modulus at high frequencies. The obtained relationship makes it possible to calculate the shear modulus and storage and loss moduli as a function of frequency, temperature, and molecular weight distribution.
9
Murphy, William, Andrew Reischer, and Kai Hsu. "Modulus decomposition of compressional and shear velocities in sand bodies." GEOPHYSICS 58, no. 2 (February 1993): 227–39. http://dx.doi.org/10.1190/1.1443408.
Повний текст джерелаАнотація:
The advent of borehole shear slowness measurements in sonically slow formations has lead to breakthroughs in the subsurface profiling of geological bodies. In sand bodies, compressional and shear velocities depend predictably on porosity, mineralogy, grain contacts, and fluid saturation. An interpretation is best performed by decomposing the velocities into moduli that are intrinsic measures of the rock frame and pore fluid compressibilities. Careful experiments on pure materials (i.e., pure quartz sandstones) demonstrate two simplifying constitutive relationships. First, the bulk and shear frame moduli are simple functions of the porosity. A comparison of the measured shear frame modulus to the prediction for the pure material distinguishes sand from shale. Second, the ratio of the bulk and shear frame moduli is a constant 0.9 independent of the porosity. The measured velocities are directly inverted to yield the bulk modulus of the pore fluid. The fluid saturation effects are so dramatic at high porosity that not only gas but oil may also be distinguished from water. The relationships are tested in several case studies where the results are encouraging. Finite‐frequency effects may complicate the interpretation where filtrate invasion is significant. Attenuation provides further information because compressional absorption is particularly sensitive to gas saturation. A potential application of the modulus decomposition may be to quantify, in amplitude versus offset seismics proximal to the well‐bore, the fractional change in shear frame modulus from the fractional change in pore fluid modulus.
10
Sadik, Tarik, Caroline Pillon, Christian Carrot, José A. Reglero Ruiz, Michel Vincent, and Noëlle Billon. "Polypropylene structural foams: Measurements of the core, skin, and overall mechanical properties with evaluation of predictive models." Journal of Cellular Plastics 53, no. 1 (July 28, 2016): 25–44. http://dx.doi.org/10.1177/0021955x16633643.
Повний текст джерелаАнотація:
Relationships for the prediction of various linear mechanical properties of polymeric sandwich foams obtained in injection processes were studied in comparison with shear, tensile, and flexural tests. The samples were obtained by a core-back foam injection molding process that enables one to obtain sandwich materials with dense skins and a foamed core as revealed by the morphological analysis. Tensile, shear, and flexural moduli were investigated for the skin, the core, and the overall foamed structure. In addition, the Poisson’s ratio of the skin was also determined. The core properties were specifically analyzed by machining the samples and removing the skins. Tensile and shear properties of the core can be well described by the Moore equation. The tensile modulus can be calculated by a linear mixing rule with the moduli of the skin and of the core in relation to the thickness of the layers. Shear and flexural moduli are described by a linear mixing rule on the rigidity in agreement with the mechanics of beams. Tensile modulus, out-of-plane shear modulus, and flexural modulus can finally be predicted by the knowledge of only very few data, namely the tensile modulus and Poisson’s ratio of the matrix, the void fraction, and thickness of the core. The equations were proved to be physically meaningful and consistent with each other.
11
Lee, Byung Jae, Seong-Hoon Kee, Taekeun Oh, and Yun-Yong Kim. "Evaluating the Dynamic Elastic Modulus of Concrete Using Shear-Wave Velocity Measurements." Advances in Materials Science and Engineering 2017 (2017): 1–13. http://dx.doi.org/10.1155/2017/1651753.
Повний текст джерелаАнотація:
The objectives of this study are to investigate the relationship between static and dynamic elastic moduli determined using shear-wave velocity measurements and to demonstrate the practical potential of the shear-wave velocity method for in situ dynamic modulus evaluation. Three hundred 150 by 300 mm concrete cylinders were prepared from three different mixtures with target compressive strengths of 30, 35, and 40 MPa. Static and dynamic tests were performed at 4, 7, 14, and 28 days to evaluate the compressive strength and the static and dynamic moduli of the cylinders. The results obtained from the shear-wave velocity measurements were compared with dynamic moduli obtained from standard test methods (P-wave velocity measurements according to ASTM C597/C597M-16 and fundamental longitudinal and transverse resonance tests according to ASTM C215-14). The shear-wave velocity measured from cylinders showed excellent repeatability with a coefficient of variation (COV) less than 1%, which is as good as that of the standard test methods. The relationship between the dynamic elastic modulus based on shear-wave velocity and the chord elastic modulus according to ASTM C469/C469M was established. Furthermore, the best-fit line for the shear-wave velocity was also demonstrated to be effective for estimating compressive strength using an empirical relationship between compressive strength and static elastic modulus.
12
Sawangsuriya, Auckpath, Tuncer B. Edil, and Peter J. Bosscher. "Relationship Between Soil Stiffness Gauge Modulus and Other Test Moduli for Granular Soils." Transportation Research Record: Journal of the Transportation Research Board 1849, no. 1 (January 2003): 3–10. http://dx.doi.org/10.3141/1849-01.
Повний текст джерелаАнотація:
Recently, there has been a concerted effort to develop methods for direct measurement of soil stiffness, modulus, or both. A new field test device called the soil stiffness gauge (SSG), which is currently marketed as GeoGauge, shows potential to assess near-surface stiffness. A comparison is presented of moduli obtained from the SSG with moduli obtained from other tests on granular soils. The maximum singleamplitude dynamic force produced during the SSG measurement is determined to be 17.3 N. On this basis, an estimate of the shear strain amplitude produced from the SSG is made by finite element analysis. A plot of shear modulus versus shear strain amplitude on a medium sand obtained from different laboratory tests, including the SSG, is presented. The comparison of the SSG modulus with the moduli from other laboratory tests indicates that the SSG outputs a dynamic modulus corresponding to a strain amplitude approximately 20 times higher than the expected range and with a magnitude lower than it should be on the basis of the induced strain. Nevertheless, the SSG modulus is still higher than that from the resilient modulus test typically used for pavement design.
13
Wu, Guofang, Yong Zhong, and Haiqing Ren. "Effects of Grain Pattern on the Rolling Shear Properties of Wood in Cross-Laminated Timber." Forests 12, no. 6 (May 25, 2021): 668. http://dx.doi.org/10.3390/f12060668.
Повний текст джерелаАнотація:
Rolling shear modulus and strength are the key factors affecting the mechanical performance of some wood products such as cross-laminated timber (CLT). As reported, rolling shear property strongly depends on the sawing pattern such as the aspect ratio and grain direction (grain mode). However, the mechanism behind this phenomenon has not yet been clarified. In this work, the rolling shear modulus and strength of spruce-pine-fir (SPF) with different grain modes and aspect ratios were experimentally investigated. In addition, a theoretical investigation was carried out to reveal the mechanism behind this phenomenon. The results exhibited that the rolling shear moduli of 0° and 90° grain-mode wood were the same. This value can be called the pure rolling shear modulus. Rolling shear modulus of wood with angles other than 0° and 90° can be calculated from the pure rolling shear modulus and grain angle. Therefore, this modulus can be called the apparent rolling shear modulus. Thus, using 0° and 90° grain-mode specimens to determine the pure rolling shear modulus and strength of wood is recommended.
14
Morozov, Igor B., and Wubing Deng. "Elastic potential and pressure dependence of elastic moduli in fluid-saturated rock with double porosity." GEOPHYSICS 83, no. 4 (July 1, 2018): MR231—MR244. http://dx.doi.org/10.1190/geo2016-0646.1.
Повний текст джерелаАнотація:
Models of seismic velocity dispersion and attenuation in porous rock are often based on quantitative relations between empirical moduli by Gassmann, Mavko-Jizba, Sayers-Kachanov, and others. All of these relations have a common origin in the concept of elastic potential; nevertheless, this concept itself has been insufficiently used in the context of multiple porosities and squirt flows. Regardless of the microstructure of a rock, knowledge of its macroscopic elastic potential reveals the complete set of parameters that are necessary and sufficient for characterizing its elasticity and obtaining rigorous equations of deformation. For isotropic rock with double (such as stiff and/or compliant) porosity, this parameter set contains six elements of the bulk-modulus matrix and six moduli for shear. The elastic matrices predict all observable elastic properties, such as bulk, shear and Young’s moduli, pore compressibilities, Skempton coefficients, consolidation parameters, Poisson’s ratios, static (Gassmann’s) and ultrasonic (Mavko-Jizba’s) undrained moduli, as well as the hypothetical high-pressure modulus [Formula: see text] and unrelaxed-frame moduli. By using laboratory observations with Westerly granite, all six elements of the elastic matrix for bulk deformation are inverted for exactly; three moduli for shear are determined with uncertainties due to insufficient data. The inverted matrices of the elastic moduli predict all observations (drained and low- and high-frequency undrained moduli) within measurement accuracy, with minor uncertainties for shear deformation. The secondary pores are approximately 50 times more compressible than are the primary ones, which explains their interpretation as “soft.” Most of the inverted elastic moduli vary with the confining pressure. Despite its usually assumed constancy, the high-pressure modulus [Formula: see text] exhibits an approximately 10% decrease with confining pressure from 0 to 100 MPa, which is opposite of the trend of the solid-grain modulus [Formula: see text].
15
Kim, Noh Yu, Hee Joon Kim, Se Woong Oh, N. Hozumi, Cheol Kyou Lee, and Min Sung Hong. "Ultrasonic Measurement of Elastic Properties of Nanostructured Alumina." Key Engineering Materials 321-323 (October 2006): 1711–14. http://dx.doi.org/10.4028/www.scientific.net/kem.321-323.1711.
Повний текст джерелаАнотація:
In this paper, elastic moduli of nanostructured alumina are evaluated by simultaneous measurement of longitudinal and shear wave velocities using mode-converted ultrasound in scanning acoustic microscope (SAM). Mode-converted longitudinal and shear waves inside alumina sample are captured to calculate acoustic wave velocities and determine elastic constants such as Young’s modulus and Bulk modulus. Al2O3 nanostructured alumina samples are formed by compacting micro-sized Al2O3 powder with nano-sized Al2O3 powder from 10wt% to 50wt%, and tested by SAM to investigate elastic moduli. A correlation is found from experiment that the more percentage of nano-particles are added, the higher elastic moduli are obtained. It is also shown that the mode-converted ultrasound is sensitive enough to characterize mechanical modulus of nanostructured alumina quantitatively.
16
KORNEEV, A. A., O. V. TAPINSKAYA, and V. N. TRONIN. "CONTINUOUS MODEL OF CRYSTAL MELTING AND DESTRUCTION." International Journal of Modern Physics B 05, no. 12 (July 20, 1991): 2073–92. http://dx.doi.org/10.1142/s0217979291000808.
Повний текст джерелаАнотація:
In this paper we show that the existence of microscopic defects (both point and linear) in the crystal lattice changes the elastic moduli of the solid. Owing to the change of the shear modulus induced by equilibrium defects, the relative shear modulus becomes temperature dependent and this dependence is close to the empirical value. For a wide class of metals, the values of the melting temperature obtained from the requirement that the shear modulus turn to zero are in good agreement with experiment.
17
Djayaprabha, Herry Suryadi, Ta-Peng Chang, and Jeng-Ywan Shih. "Comparison Study of Dynamic Elastic Moduli of Cement Mortar and No-cement Slag Based Cementitious Mortar Activated with Calcined Dolomite with Impulse Excitation Technique." MATEC Web of Conferences 186 (2018): 02004. http://dx.doi.org/10.1051/matecconf/201818602004.
Повний текст джерелаАнотація:
This paper presents the comparison of an experimental investigation on compressive strength and dynamic elastic moduli of mortars made of Ordinary Portland Cement (OPC) and ground granulated blast furnace slag (GGBFS) incorporating with calcined dolomite. Dolomite powder calcined at temperature 900°C emerged as a GGBFS activator for producing cementitious mortar binder. In this study, no-cement mortar is made by activating GGBFS with calcined dolomite by a fixed amount of 20 wt%. The compressive strengths and dynamic elastic moduli were measured at 7 and 28 days. Comparing with cement mortar, the compressive strength of no-cement mortar was found about 54.4 and 46.9% lower at ages of 7 and 28 days, respectively. Non-destructive evaluation of the dynamic elastic moduli was investigated by impulse excitation technique (IET). It measures the resonant frequencies of induced vibration signal in the flexural and torsional mode for determining the dynamic Young's modulus and the dynamic shear modulus. The Poisson's ratio was calculated by the dynamic Young's modulus and the dynamic shear modulus relationship. The results showed that the 28-day dynamic Young's and shear moduli of cement mortar were 31.91 and 14.43 GPa, respectively. The dynamic Young's and shear moduli of no-cement mortar were lower by 23.3 and 15.2% than that of cement mortar at the age of 28 days. The obtained results showed that the 28-day Poisson's ratio of no-cement mortar had a wider range between 0.177 and 0.209 than that of cement mortar which ranged from 0.180 to 0.185.
18
Bazˇant, Z. P. "Shear Buckling of Sandwich, Fiber Composite and Lattice Columns, Bearings, and Helical Springs: Paradox Resolved." Journal of Applied Mechanics 70, no. 1 (January 1, 2003): 75–83. http://dx.doi.org/10.1115/1.1509486.
Повний текст джерелаАнотація:
As shown three decades ago, in situations where the initial stresses before buckling are not negligible compared to the elastic moduli, the geometrical dependence of the tangential moduli on the initial stresses must be taken into account in stability analysis, and the stability or bifurcation criteria have different forms for tangential moduli associated with different choices of the finite strain measure. So it has appeared paradoxical that, for sandwich columns, different but equally plausible assumptions yield different formulas, Engesser’s and Haringx’ formulas, even though the axial stress in the skins is negligible compared to the axial elastic modulus of the skins and the axial stress in the core is negligible compared to the shear modulus of the core. This apparent paradox is explained by variational energy analysis. It is shown that the shear stiffness of a sandwich column, provided by the core, generally depends on the axial force carried by the skins if that force is not negligible compared to the shear stiffness of the column (if the column is short). The Engesser-type, Haringx-type, and other possible formulas associated with different finite strain measures are all, in principle, equivalent, although a different shear stiffness of the core, depending linearly on the applied axial load, must be used for each. The Haringx-type formula, however, is most convenient because it represents the only case in which the shear modulus of the core can be considered to be independent of the axial force in the skins and to be equal to the shear modulus measured in simple shear tests (e.g., torsional test). Extensions of the analysis further show that Haringx’s formula is preferable for a highly orthotropic composite because a constant shear modulus of the soft matrix can be used for calculating the shear stiffness of the column, and further confirm that Haringx’s buckling formula with a constant shear stiffness is appropriate for helical springs and built-up columns (laced or battened).
19
Singh, D., G. Dombe, C. Bhongale, P. P. Singh, Mehilal Maurya, and B. Bhattacharya. "Shear Thickening Behaviour of Composite Propellant Suspension under Oscillatory Shear." Defence Science Journal 66, no. 3 (April 25, 2016): 222. http://dx.doi.org/10.14429/dsj.66.8849.
Повний текст джерелаАнотація:
Composite propellant suspensions consist of highly filled polymeric system wherein solid particles of different sizes and shapes are dispersed in a polymeric matrix. The rheological behaviour of a propellant suspension is characterised by viscoplasticity and shear rate and time dependant viscosity. The behaviour of composite propellant suspension has been studied under amplitude sweep test where tests were performed by continuously varying strain amplitude (strain in %, γ) by keeping the frequency and temperature constant and results are plotted in terms of log γ (strain amplitude) vs logGʹ and logGʺ (Storage modulus and loss modulus, respectively). It is clear from amplitude sweep test that dynamic moduli and complex viscosity show marked increase at critical strain amplitude after a plateau region, infering a shear thickening behaviour.
20
Rossato, Gianni, and Paolo Simonini. "Stress–strain behaviour of sands in triaxial and direct simple shear tests." Canadian Geotechnical Journal 28, no. 2 (April 1, 1991): 276–81. http://dx.doi.org/10.1139/t91-033.
Повний текст джерелаАнотація:
The behaviour of a natural sand in triaxial compression and direct simple shear tests was compared by means of dimensionless analysis of parameters controlling the evolution of stresses and strains. The secant triaxial compression and direct simple shear moduli were interpreted in a dimensionless form. A criterion based on the equivalence between major principal strain in the two tests was considered to compare the results. Key words: sand, stress–strain behaviour, triaxial test, direct simple shear test, shear modulus, triaxial compression modulus.
21
Lefebvre, Guy, Denis Leboeuf, Muhsin E. Rahhal, Alain Lacroix, Joseph Warde, and Kenneth H. Stokoe II. "Laboratory and field determinations of small-strain shear modulus for a structured Champlain clay." Canadian Geotechnical Journal 31, no. 1 (February 1, 1994): 61–70. http://dx.doi.org/10.1139/t94-007.
Повний текст джерелаАнотація:
Values of small-strain shear modulus Gmax, for a Champlain Sea clay deposit were obtained both under an embankment built 18 years ago, and outside of the area influenced by this embankment. The small-strain shear moduli Gmax were measured in the laboratory by using resonant column tests and in the field by spectral analysis of surface waves. In addition to verifying the two methods, comparison of the in situ and laboratory values allowed evaluation of the influence of the sampling and the need to correct the laboratory values to account for the age of the deposit. The test program also made it possible to verify the influence of the deposit's consolidation and the existing models predicting small-strain shear moduli in clay deposits. Key words : shear modulus, shear-wave velocity, resonant column, in situ test, surface waves, soft clay.
22
Yasuda, Nario, and Norihisa Matsumoto. "Comparisons of deformation characteristics of rockfill materials using monotonic and cyclic loading laboratory tests and in situ tests." Canadian Geotechnical Journal 31, no. 2 (April 1, 1994): 162–74. http://dx.doi.org/10.1139/t94-022.
Повний текст джерелаАнотація:
The deformation characteristics of rockfill materials at very small strains were investigated by comparing the results of monotonic and cyclic loading laboratory tests with geophysical P- and S-wave logging data from the field. Using a precision linear variable differential transformer for displacement, the elastic moduli of rockfill materials at very small strains were measured in monotonic and cyclic loading triaxial tests. The laboratory test results agreed well with the field results. The shear moduli of rockfill materials from both a monotonic loading torsional simple shear test and a cyclic loading torsional simple shear test also showed good correspondence. Furthermore, the shear modulus predicted from the in situ shear wave tests in rockfill dams corresponded reasonably well with the modulus in the large-scale triaxial tests in the laboratory. Key words : deformation characteristics, embankment dams, rockfill materials, laboratory test, in situ test.
23
Tang, Xing Ling, Abdelkhalak El Hami, and Khalil El-Hami. "Mechanical Properties Investigation of Single-Walled Carbon Nanotube Using Finite Element Method." Key Engineering Materials 550 (April 2013): 179–87. http://dx.doi.org/10.4028/www.scientific.net/kem.550.179.
Повний текст джерелаАнотація:
This paper presents a three dimensional finite element model for armchair, zigzag and chiral single-walled carbon nanotubes (SWCNTs). The influences of diameter, chirality and length on the elastic moduli (Young’s modulus and shear modulus) of SWCNTs are investigated. The formulation presented is based on the assumption of viewing the construction of SWCNTs as a geometric frame-like structure. The interatomic interactions of bond length, bond angle, bond torsion and non-bonded interactions are equivalent to corresponding structure features straightforwardly. The models of SWCNTs are developed according to the atomistic structure network of nanotubes. The interatomic interactions of C- C atoms are simulated via appropriate straight spring and torsional spring elements. The computational results indicate that both diameter and chirality have a significant effect on the Young’s and shear moduli of SWCNTs, while the elastic moduli are not very sensitive to the variation of length. It is also shown that with a similar radius, armchair SWCNT has a slight higher value of Young’s modulus than zigzag and chiral SWCNTs. While zigzag SWCNT has a slight higher value of shear modulus than armchair and chiral SWCNTs.
24
Ng, Robert M. C., and K. Y. Lo. "The measurements of soil parameters relevant to tunnelling in clays." Canadian Geotechnical Journal 22, no. 3 (August 1, 1985): 375–91. http://dx.doi.org/10.1139/t85-049.
Повний текст джерелаАнотація:
A comprehensive laboratory program was carried out on specimens trimmed from 152 mm diameter piston samples of a soft silty clay and a varved clay at a tunnel site in Thunder Bay. Results of conventional triaxial tests as well as special tests for the determination of anisotropic elastic parameters, simple shear tests, and stress path tests are presented.Results indicate that the unloading moduli are about twice the loading moduli, the Poisson's ratios in unloading are about three times those in loading, but the independent shear modulus is relatively unaffected. While the modulus is sensitive to mode of consolidation, drainage, and direction of stress path, the stress states at failure of all the different types of tests fall close to a single envelope for compression and extension. The choice of soil parameters for the analysis of deformation in tunnelling in soft clays is discussed. Key words: clay, tunnelling, stress path, deformation modulus, shear modulus, anisotropic elastic parameters, failure envelope.
25
Qin, Hongbo, Tianfeng Kuang, Xinghe Luan, Wangyun Li, Jing Xiao, Ping Zhang, Daoguo Yang, and Guoqi Zhang. "Influence of Pressure on the Mechanical and Electronic Properties of Wurtzite and Zinc-Blende GaN Crystals." Crystals 8, no. 11 (November 14, 2018): 428. http://dx.doi.org/10.3390/cryst8110428.
Повний текст джерелаАнотація:
The mechanical and electronic properties of two GaN crystals, wurtzite and zinc-blende GaN, under various hydrostatic pressures were investigated using first principles calculations. The results show that the lattice constants of the two GaN crystals calculated in this study are close to previous experimental results, and the two GaN crystals are stable under hydrostatic pressures up to 40 GPa. The pressure presents extremely similar trend effect on the volumes of unit cells and average Ga-N bond lengths of the two GaN crystals. The bulk modulus increases while the shear modulus decreases with the increase in pressure, resulting in the significant increase of the ratios of bulk moduli to shear moduli for the two GaN polycrystals. Different with the monotonic changes of bulk and shear moduli, the elastic moduli of the two GaN polycrystals may increase at first and then decrease with increasing pressure. The two GaN crystals are brittle materials at zero pressure, while they may exhibit ductile behaviour under high pressures. Moreover, the increase in pressure raises the elastic anisotropy of GaN crystals, and the anisotropy factors of the two GaN single crystals are quite different. Different with the obvious directional dependences of elastic modulus, shear modulus and Poisson’s ratio of the two GaN single crystals, there is no anisotropy for bulk modulus, especially for that of zinc-blende GaN. Furthermore, the band gaps of GaN crystals increase with increasing pressure, and zinc-blende GaN has a larger pressure coefficient. To further understand the pressure effect on the band gap, the band structure and density of states (DOSs) of GaN crystals were also analysed in this study.
26
Hu, Jin-Lian, and Yi-Tong Zhang. "The KES Shear Test for Fabrics." Textile Research Journal 67, no. 9 (September 1997): 654–64. http://dx.doi.org/10.1177/004051759706700904.
Повний текст джерелаАнотація:
Many fabric mechanics researchers have reported that specimens being tested on the KES shear tester are not subjected to pure shear deformation; therefore, test results cannot lead directly to a determination of the fabric shear modulus and stress/strain relationship, particularly in the nonlinear range of stress-strain. Combined with finite element analysis, this paper presents an analytical solution for the distribution of shear stresses and strains in fabric specimens tested on the kes tester. A fabric is treated as an orthotropic sheet during the analysis, which leads to a closed-form solution for the shear modulus as a function of fabric tensile and shear moduli from the kes shear test. A modified shear stress-strain relationship can also be derived. From calculations for fabrics used here, the difference between modified and tested shear modulus values is about 25–30%. The study also suggests that although the shear modulus and curves obtained on the kes shear tester are significantly different from those under the pure shear state, the kes results can still reflect the nature of a fabric under shear deformation and are valid for general objective evaluations. The exact shear stress-strain relationship and actual shear modulus may be modified only when they are required for fabric complex deformation analysis.
27
Yu, Jing, Yongmei Zhang, Yuhong Zhao, and Yue Ma. "Anisotropies in Elasticity, Sound Velocity, and Minimum Thermal Conductivity of Low Borides VxBy Compounds." Metals 11, no. 4 (April 1, 2021): 577. http://dx.doi.org/10.3390/met11040577.
Повний текст джерелаАнотація:
Anisotropies in the elasticity, sound velocity, and minimum thermal conductivity of low borides VB, V5B6, V3B4, and V2B3 are discussed using the first-principles calculations. The various elastic anisotropic indexes (AU, Acomp, and Ashear), three-dimensional (3D) surface contours, and their planar projections among different crystallographic planes of bulk modulus, shear modulus, and Young’s modulus are used to characterize elastic anisotropy. The bulk, shear, and Young’s moduli all show relatively strong degrees of anisotropy. With increased B content, the degree of anisotropy of the bulk modulus increases while those of the shear modulus and Young’s modulus decrease. The anisotropies of the sound velocity in the different planes show obvious differences. Meanwhile, the minimum thermal conductivity shows little dependence on crystallographic direction.
28
Fukunaga, Hisao, and Hideki Sekine. "A Laminate Design for Elastic Properties of Symmetric Laminates with Extension-Shear or Bending-Twisting Coupling." Journal of Composite Materials 28, no. 8 (May 1994): 708–31. http://dx.doi.org/10.1177/002199839402800802.
Повний текст джерелаАнотація:
A laminate design method for elastic properties of symmetric laminates with extension-shear or bending-twisting coupling is presented using lamination parameters which give a complete expression of laminate configurations. The elastic properties of Young's moduli, Poisson's ratios and shear modulus are represented on the lamination parameter plane. A general method is also developed for determining laminate configurations corresponding to lamination parameters. The graphical representation clarifies the relation between laminate configurations and elastic properties. Effects of extension-shear coupling on in-plane elastic properties are discussed. The elastic properties of Young's moduli and shear modulus have the maximum values when the coupling terms vanish. Two design examples are also presented which utilize bending-twisting couplings. One is concerned with the control of a cross-coupling parameter in an aeroelastic tailoring of a composite wing, and the other is concerned with the shear buckling optimization of a symmetric laminated plate.
29
Ledbetter, H. M., and S. A. Kim. "Molybdenum effect on Fe–Cr–Ni-alloy elastic constants." Journal of Materials Research 3, no. 1 (February 1988): 40–44. http://dx.doi.org/10.1557/jmr.1988.0040.
Повний текст джерелаАнотація:
This study involved the ultrasonic measurement of the polycrystalline elastic constants of six face-centered-cubic Fe–Cr–Ni alloys, nominally Fe–19Cr–12Ni (at. %). In these alloys, Mo content ranged up to 2.4 at. %. Molybdenum lowers the Young and shear moduli, and it raises the Poisson ratio. Against expectation (because it increases volume), Mo raises the bulk modulus. Qualitatively, the results show that Ni raises the bulk modulus and Poisson ratio; but Ni lowers the Young and shear moduli. (Nickel decreases the alloy's atomic volume.) The discussion includes existing models based on 3d-electron theory.
30
Khazanehdari, Jalal, and Jeremy Sothcott. "Variation in dynamic elastic shear modulus of sandstone upon fluid saturation and substitution." GEOPHYSICS 68, no. 2 (March 2003): 472–81. http://dx.doi.org/10.1190/1.1567213.
Повний текст джерелаАнотація:
Experimental acoustic measurements on sandstone rocks at both sonic and ultrasonic frequencies show that fluid saturation can cause a noticeable change in both the dynamic bulk and shear elastic moduli of sandstones. We observed that the change in dynamic shear modulus upon fluid saturation is highly dependent on the type of saturant, its viscosity, rock microstructure, and applied pressures. Frequency dispersion has some influence on dynamic elastic moduli too, but its effect is limited to the ultrasonic frequency ranges and above. We propose that viscous coupling, reduction in free surface energy, and, to a limited extent, frequency dispersion due to both local and global flow are the main mechanisms responsible for the change in dynamic shear elastic modulus upon fluid saturation and substitution, and we quantify influences.
31
Cherepetskaya, Elena B., Alexander A. Karabutov, Vladimir A. Makarov, Elena A. Mironova, Ivan A. Shibaev, Nikolay G. Vysotin, and Dmitry V. Morozov. "Internal Structure Research of Shungite by Broadband Ultrasonic Spectroscopy." Key Engineering Materials 755 (September 2017): 242–47. http://dx.doi.org/10.4028/www.scientific.net/kem.755.242.
Повний текст джерелаАнотація:
The internal structure of plane-parallel plates of shungite is studied. The broadband ultrasonic pulses are used to measure the velocities of longitudinal and shear elastic ultrasonic waves. The accuracy of measurements is 0.3% in the case of longitudinal wave velocity and 0.5% in the case of shear wave velocity (scanning pitch over the surface of specimens was 0.5 mm). Local elastic moduli of shungite (Young modulus, shear modulus and Poisson's ratio) are uniquely determined from the velocities of elastic waves.
32
Ball, Vincent. "Crosslinking of Bovine Gelatin Gels by Genipin Revisited Using Ferrule-Top Micro-Indentation." Gels 9, no. 2 (February 10, 2023): 149. http://dx.doi.org/10.3390/gels9020149.
Повний текст джерелаАнотація:
(1) Background: Gelatin is widely used in food science, bioengineering, and as a sealant. However, for most of those applications, the mechanical properties of gelatin gels need to be improved by means of physical or chemical crosslinking. Among the used chemical agents, genipin allows low cytotoxicity in addition to improved Young’s modulus. However, the mechanical properties of gelatin–genipin gels have only been investigated at the macroscale, and there is no knowledge of the influence of the genipin concentration on the surface homogeneity of Young’s modulus. (2) Methods: To this aim, the influence of genipin concentration on Young’s modulus of gelatin gels was investigated by means of ferrule-top micro-indentation. The data were compared with storage moduli obtained by shear rheology data. (3) Results: Ferrule-top indentation measurements allowed us to show that Young’s moduli of gelatin–genipin gels increase up to a plateau value after approximately 12 mg/mL in genipin and 4 h of crosslinking. Young’s moduli distribute with high homogeneity over 80 µm × 80 µm surface areas and are consistent with the storage moduli obtained by shear rheology. (4) Conclusions: It has been shown that ferrule-top indentation data fitted with the Hertz model yield Young’s moduli of gelatin–genipin gels which are consistent with the storage moduli obtained by characterization at the macroscale using shear rheometry. In addition, Young’s moduli are homogenously distributed (with some irregularities at the highest genipin concentrations) and can be increased by two orders of magnitude with respect to the uncrosslinked gel.
33
Tan, Xin, Zhen Yang Xin, Xue Jie Liu, and Qing Ge Mu. "First-Principles Study on Elastic Properties of AlN." Advanced Materials Research 821-822 (September 2013): 841–44. http://dx.doi.org/10.4028/www.scientific.net/amr.821-822.841.
Повний текст джерелаАнотація:
Structural and elastic properties of AlN are investigated by using First-principles. Both of wurtzite and zinc-blende structures are investigated, respectively. The bulk moduli of the wurtzite structure and zinc blende AlN are 194.2GPa and 187GPa, which obtained by the elastic stiffness constants respectively. Shear moduli are 136GPa and 124GPa. Young's moduli are 331GPa and 305GPa. Poisson's ratio and Pugh criterion suggests that both of them are brittle material. The brittleness of wurtzite AlN is higher than that of zinc-blende AlN. The elastic anisotropy of the bulk moduli and shear moduli were discussed. Three-dimensional anisotropic of the young's modulus were analyzed.
34
Gordaninejad, Faramarz, Xiaojie Wang, and Praveen Mysore. "Behavior of thick magnetorheological elastomers." Journal of Intelligent Material Systems and Structures 23, no. 9 (June 2012): 1033–39. http://dx.doi.org/10.1177/1045389x12448286.
Повний текст джерелаАнотація:
In this study, the behavior of thick magnetorheological elastomers is experimentally investigated. Two types of magnetorheological elastomer specimens of varying concentrations, with circular and rectangular shapes having thicknesses from 6.35 mm to a maximum of 25.4 mm, are prepared. The magnetorheological elastomer samples are studied under quasi-static compression and double lap-shear tests. The shear and the Young’s moduli of the magnetorheological elastomers are obtained under different applied magnetic fields. It is observed that the field-induced change in the modulus is independent of the thickness of the magnetorheological elastomer and is only dependent on the iron particle concentration and the magnetic field strength. With the increase in the applied magnetic field, it is observed that the change in modulus varies from a linear behavior at lower applied magnetic fields to a nonlinear one at higher magnetic fields. It is found that compressive and shear moduli only depend on the applied magnetic fields and are independent of the sample thickness. In addition, the maximum induced change in material modulus under compression is shown to be 99%, whereas in shear it is found to be 68% when compared to its off-state.
35
Zhang, Zhiying, Veerle Keppens, Peter K. Liaw, Yoshihiko Yokoyama, and Akihisa Inoue. "Elastic properties of Zr-based bulk metallic glasses studied by resonant ultrasound spectroscopy." Journal of Materials Research 22, no. 2 (February 2007): 364–67. http://dx.doi.org/10.1557/jmr.2007.0040.
Повний текст джерелаАнотація:
We report measurements of the elastic properties of Zr-based bulk metallic glasses, Zr52.5Cu17.9Ni14.6Al10Ti5, Zr50Cu30Ni10Al10, and Zr50Cu40Al10 between 5 K and 300 K. Both the shear and longitudinal modulus have been measured as a function of temperature, allowing accurate determination of the Poisson’s ratio and the related ratio of bulk modulus to shear modulus, K/G. These data make it possible to assess the influence of the alloy’s composition on the mechanical properties and enable an evaluation of the correlation between the elastic moduli and the ductility of the alloys.
36
Toyota, Hirofumi, and Susumu Takada. "Effects of gravel content on liquefaction resistance and its assessment considering deformation characteristics in gravel – mixed sand." Canadian Geotechnical Journal 56, no. 12 (December 2019): 1743–55. http://dx.doi.org/10.1139/cgj-2018-0575.
Повний текст джерелаАнотація:
Many reports describe overestimation of liquefaction resistance based on sounding data related to ground materials containing coarse particles such as gravel and cobbles. Better methods of liquefaction potential estimation must be developed using investigation data other than those from sounding. Gathering perfect and undisturbed samples is difficult, but using seismic methods such as PS logging might be effective for assessing liquefaction potential. For this study, bender element (BE) tests and local small strain (LSS) tests were conducted, respectively, to measure the dynamic and static shear moduli of gravel – mixed sand specimens. Subsequently, relations between liquefaction strength and secant shear moduli were examined to provide reliable estimation of liquefaction in gravel – mixed sand. Although the liquefaction resistance increased considerably with overconsolidation, the initial shear modulus exhibited only a slight change with the same overconsolidation. The experimentally obtained results elucidated that the important shear strain level, for which secant shear modulus has a strong relation with liquefaction strength, was not a linear elastic region of 0.001%: it was about 0.01%.
37
Wang, Jian, Hongbo Qin, Junfu Chen, Daoguo Yang, and Guoqi Zhang. "First-Principles Study on the Elastic Mechanical Properties and Anisotropies of Gold–Copper Intermetallic Compounds." Metals 12, no. 6 (June 2, 2022): 959. http://dx.doi.org/10.3390/met12060959.
Повний текст джерелаАнотація:
In this study, first-principles calculations were utilized to investigate the lattice constants, elastic constants, and mechanical properties of gold–copper (Au–Cu) intermetallic compounds (IMCs), including AuCu3, AuCu, and Au3Cu. We also verified the direction dependence of the Young’s modulus, shear modulus, and Poisson’s ratio of the compounds. The calculated lattice parameters agreed with the experimental data, and the single-crystal elastic constants, elastic modulus E, shear modulus G, bulk modulus B, and Poisson’s ratio ν were calculated. For the Young’s and shear moduli, AuCu3 showed the highest anisotropy, followed by AuCu and Au3Cu. The Poisson’s ratios of AuCu3 and Au3Cu crystals were isotropic on (100) and (111) crystal planes and anisotropic on the (110) crystal plane. However, the Poisson’s ratio of the AuCu crystal was anisotropic on (100) and (111) crystal planes and isotropic on the (110) crystal plane.
38
Silva, Miguel R., João A. Dias-de-Oliveira, António M. Pereira, Nuno M. Alves, Álvaro M. Sampaio, and António J. Pontes. "Design of Kinematic Connectors for Microstructured Materials Produced by Additive Manufacturing." Polymers 13, no. 9 (May 6, 2021): 1500. http://dx.doi.org/10.3390/polym13091500.
Повний текст джерелаАнотація:
The main characteristic of materials with a functional gradient is the progressive composition or the structure variation across its geometry. This results in the properties variation in one or more specific directions, according to the functional application requirements. Cellular structure flexibility in tailoring properties is employed frequently to design functionally-graded materials. Topology optimisation methods are powerful tools to functionally graded materials design with cellular structure geometry, although continuity between adjacent unit-cells in gradient directions remains a restriction. It is mandatory to attain a manufacturable part to guarantee the connectedness between adjoining microstructures, namely by ensuring that the solid regions on the microstructure’s borders i.e., kinematic connectors) match the neighboring cells that share the same boundary. This study assesses the kinematic connectors generated by imposing local density restrictions in the initial design domain (i.e., nucleation) between topologically optimised representative unit-cells. Several kinematic connector examples are presented for two representatives unit-cells topology optimised for maximum bulk and shear moduli with different volume fractions restrictions and graduated Young’s modulus. Experimental mechanical tests (compression) were performed, and comparison studies were carried out between experimental and numerical Young’s modulus. The results for the single maximum bulk for the mean values for experimental compressive Young’s modulus (Ex¯) with 60%Vf show a deviation of 9.15%. The single maximum shear for the experimental compressive Young’s modulus mean values (Ex¯) with 60%Vf, exhibit a deviation of 11.73%. For graded structures, the experimental mean values of compressive Young’s moduli (Ex¯), compared with predicted total Young’s moduli (ESe), show a deviation of 6.96 for the bulk graded structure. The main results show that the single type representative unit-cell experimental Young’s modulus with higher volume fraction presents a minor deviation compared with homogenized data. Both (i.e., bulk and shear moduli) graded microstructures show continuity between adjacent cells. The proposed method proved to be suitable for generating kinematic connections for the design of shear and bulk graduated microstructured materials.
39
Sharma, Sumit, Pramod Kumar, and Rakesh Chandra. "Carbon nanotube reinforced titanium composites: An experimental and molecular dynamics study." Journal of Composite Materials 52, no. 29 (May 4, 2018): 4117–23. http://dx.doi.org/10.1177/0021998318774931.
Повний текст джерелаАнотація:
In this study, the mechanical properties of carbon nanotube reinforced titanium (CNT–Ti) composites have been predicted using molecular dynamics approach. An experimental study was also conducted in which spark plasma sintering was used for preparing the composites. The effect of variation in carbon nanotube volume fraction ( V f), temperature, and strain on the elastic moduli ( E11, E22, and E33) and the shear modulus ( G Reuss) of CNT–Ti composites was studied. The elastic and shear moduli were all found to increase significantly because of the increasing carbon nanotube V f. Even at temperatures approaching 1 K, the CNT–Ti composites show high values of elastic and shear moduli. The elastic moduli tend to attain a constant value at high levels of strain. The results obtained from experiments corroborated the molecular dynamics results.
40
Amin Matori, Khamirul, Mohd Hafiz Mohd Zaid, Hock Jin Quah, Sidek Hj Abdul Aziz, Zaidan Abdul Wahab, and Mohd Sabri Mohd Ghazali. "Studying the Effect of ZnO on Physical and Elastic Properties of (ZnO)x(P2O5)1−xGlasses Using Nondestructive Ultrasonic Method." Advances in Materials Science and Engineering 2015 (2015): 1–6. http://dx.doi.org/10.1155/2015/596361.
Повний текст джерелаАнотація:
Binary zinc phosphate glass system with composition of (ZnO)x(P2O5)1−x, (x= 0.1, 0.2, 0.3, 0.4, 0.5 and 0.6 mol%) was successfully prepared using a conventional melt-quenching method. Composition dependence of physical properties and elastic properties in the (ZnO)x(P2O5)1−xwere discussed in association with the effects of adding zinc oxide (ZnO) as a modifier. The addition of ZnO modifier was expected to produce substantial changes on physical properties of the phosphate glasses. An increase in density values of the phosphate glasses was observed. Elastic moduli were studied by measuring ultrasonic longitudinal and shear velocities (VlandVt) of the glasses at room. Longitudinal modulus, shear modulus, bulk modulus, Young’s modulus, Poisson’s ratio, and Debye temperature(θD)were derived from both data of velocities and respective density of all of the samples. Findings from present work showed dependence of density and elastic moduli of each ZnO-P2O5series on glass composition.
41
Han, R., M. S. Ingber, and S. C. Hsiao. "Limitations on the Use of Effective Properties for Multicomponent Materials." Journal of Mechanics 24, no. 1 (March 2008): 95–102. http://dx.doi.org/10.1017/s1727719100001593.
Повний текст джерелаАнотація:
ABSTRACTMulticomponent composite materials comprised of a dispersed phase suspended in a matrix material are important in a wide variety of scientific and engineering applications including electronic encapsulation, functionally graded materials, and fiber-reinforced structural components among others. Modelling of this class of composites is typically performed using an effective property approach. This approach presumes that the characteristic dimension of the dispersed phase elements is small in comparison to the characteristic length scale of the physical problem under consideration. However, it is not possible to predict a third effective elastic property based on two independent effective elastic properties as it is for homogeneous elastic isotropic materials. Therefore, a macroscale simulation based on an effective Young's modulus and Poisson ratio may yield poor results for a material subjected to shear loading since there is a potentially incorrect presumed effective shear modulus for the simulation. In the current research, boundary element simulations are performed for mesoscopic samples of composite materials to determine effective bulk moduli, shear moduli, Young's moduli, and Poisson ratios. From these analyses, limitations in the effective property approach can be examined.
42
Miyamoto, Naokazu, and Kosuke Hirata. "Moderate Associations of Muscle Elasticity of the Hamstring with Hip Joint Flexibility." International Journal of Sports Medicine 40, no. 11 (August 19, 2019): 717–24. http://dx.doi.org/10.1055/a-0981-7282.
Повний текст джерелаАнотація:
AbstractThe main purpose of the present study was to identify whether and to what extent the individual differences in range of motion and stiffness of the hip joint can account for that in muscle elasticity of the hamstring. Hip extension torque and shear moduli (a measure of elasticity) of the biceps femoris, semitendinosus, and semimembranosus were assessed in 21 young males during unilateral passive hip flexion in the knee-extended position from the anatomical position to the individual’s maximal hip flexion angle. Muscle shear modulus was quantified by using ultrasound shear wave elastography. The maximal hip flexion angle correlated negatively with the shear modulus of each muscle (−0.750 ≤ r ≤ −0.612). The joint stiffness correlated positively with the shear modulus of each muscle (0.711 ≤ r ≤ 0.747). These findings suggest that hip flexion ROM and joint stiffness can reflect significantly but only moderately the muscle elasticity of the hamstring.
43
Zhu, Xuefeng, Longkun Xu, Xiaochen Liu, Jinting Xu, Ping Hu, and Zheng-Dong Ma. "Theoretical prediction of mechanical properties of 3D printed Kagome honeycombs and its experimental evaluation." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 233, no. 18 (July 16, 2019): 6559–76. http://dx.doi.org/10.1177/0954406219860538.
Повний текст джерелаАнотація:
Kagome honeycomb structure is proved to incorporate excellent mechanical and actuation performances due to its special configuration. However, until now, the mechanical properties of 3D printed Kagome honeycomb have not been investigated. Hence, the objective of this work is to explore some mechanical properties of 3D-printed Kagome honeycomb structures such as elastic properties, buckling, and so on. In this paper, the analytical formulas of some mechanical properties of Kagome honeycombs made of 3D-printed materials are given. Effective elastic moduli such as Young's modulus, shear modulus, and Poisson's ratio of orthotropic Kagome honeycombs under in-plane compression and shear are derived in analytical forms. By these formulas, we investigate the relationship of the elastic moduli, the relative density, and the shape anisotropy–ratio of 3D-printed Kagome honeycomb. By the uniaxial tensile testing, the effective Young's moduli of 3D printed materials in the lateral and longitudinal directions are obtained. Then, by the analytical formulas and the experimental results, we can predict the maximum Young's moduli and the maximum shear modulus of 3D-printed Kagome honeycombs. The isotropic behavior of 3D-printed Kagome honeycombs is investigated. We also derived the equations of the initial yield strength surfaces and the buckling surfaces. We found that the sizes of the buckling surfaces of 3D printed material are smaller than that of isotropic material. The efficiency of the presented analytical formulas is verified through the tensile testing of 3D printed Kagome honeycomb specimens.
44
McAleavey, Stephen, Manoj Menon, and Etana Elegbe. "Shear Modulus Imaging with Spatially-Modulated Ultrasound Radiation Force." Ultrasonic Imaging 31, no. 4 (October 2009): 217–34. http://dx.doi.org/10.1177/016173460903100401.
Повний текст джерелаАнотація:
The application of Spatially-Modulated Ultrasound Radiation Force (SMURF) to shear modulus imaging is demonstrated in tissue-mimicking phantoms and porcine liver. Scanning and data acquisition was performed with a Siemens Antares ultrasound scanner and VF7-3 linear array operating at 4.21 MHz. Modulus estimates in uniform phantoms of Zerdine with shear moduli of 5.1 and 12.4 kPa exhibited standard deviations within 6% of the mean value. Zerdine spheres 1 cm in diameter (nominally 2.7, 4.7 and 15 kPa) in a 8 kPa (nominal) background are clearly resolved. Cross sectional images of a soft conical inclusion in a gelatin-based phantom indicate a spatial resolution of approximately 2.5 mm. Images of the shear modulus of an ex-vivo sample of porcine liver tissue show an average value of 3 kPa. A stiff lesion induced with 0.5 mL of 10% glutaraldehyde is clearly visible as a region of shear modulus in excess of 10 kPa. A modulus gradient associated with the diffusion of the glutaraldehyde is visible. Two pulse sequences were examined, differing only in the timing of the beams used to generate the shear waves. Details of the beam sequences and subsequent signal processing are presented.
45
Kubojima, Yoshitaka, and Mario Tonosaki. "Young’s and shear moduli of glued laminated timber composed of different species obtained by a flexural vibration test." Holzforschung 66, no. 7 (October 1, 2012): 871–75. http://dx.doi.org/10.1515/hf-2011-0209.
Повний текст джерелаАнотація:
Abstract The applicability of the flexural vibration test to determine the elastic constants of glued laminated timber (GLT) composed of five wood species (ash, Fraxinus spaethiana Lingelsh.; balsa, Ochroma pyramidale Urban.; Japanese cedar, Cryptomeria japonica D. Don; Japanese red pine, Pinus densiflora Sieb. et Zucc.; Sitka spruce, Picea sitchensis Carr.) has been investigated. GLT models were prepared from four laminae with dimensions of 30 (R)×5 (T)×300 (L) mm3. The suitability of Japanese cedar for inner layers in GLTs was tested by flexural vibration test to determine the elastic constants of the laminae and the glued laminated timber. The Young’s and shear moduli were calculated by the Goens-Hearmon regression method based on the Timoshenko theory of bending (TGH method), and the results were compared with the estimated values based on the Young’s and shear moduli measured individually of each lamina. The simple lamination theory was found to be applicable for Young’s modulus but not to shear modulus. The result obtained based on the lamination theory from the shear strain energy was similar to that obtained by the TGH method.
46
Niederwestberg, Jan, Jianhui Zhou, and Ying-Hei Chui. "Comparison of Theoretical and Laboratory Out-of-Plane Shear Stiffness Values of Cross Laminated Timber Panels." Buildings 8, no. 10 (October 22, 2018): 146. http://dx.doi.org/10.3390/buildings8100146.
Повний текст джерелаАнотація:
The lay-up of cross laminated timber (CLT) leads to significant differences in properties over its cross-section. Particularly the out-of-plane shear behavior of CLT is affected by the changes in shear moduli over the cross-section. Results from laboratory shear tests are used to evaluate the shear stiffness of 3- and 5-layer CLT panels in their major and minor strength direction. The results are compared to calculated shear stiffness values on evaluated single-layer properties as well as commonly used property ratios using the Timoshenko beam theory and the shear analogy method. Differences between the two calculation approaches are pointed out. The shear stiffness is highly sensitive to the ratio of the shear modulus parallel to the grain to the shear modulus perpendicular to the grain. The stiffness values determined from two test measurements are compared with the calculated results. The level of agreement is dependent on the number of layers in CLT and the property axis of the CLT panels.
47
Goodrich, Carl P., Andrea J. Liu, and James P. Sethna. "Scaling ansatz for the jamming transition." Proceedings of the National Academy of Sciences 113, no. 35 (August 10, 2016): 9745–50. http://dx.doi.org/10.1073/pnas.1601858113.
Повний текст джерелаАнотація:
We propose a Widom-like scaling ansatz for the critical jamming transition. Our ansatz for the elastic energy shows that the scaling of the energy, compressive strain, shear strain, system size, pressure, shear stress, bulk modulus, and shear modulus are all related to each other via scaling relations, with only three independent scaling exponents. We extract the values of these exponents from already known numerical or theoretical results, and we numerically verify the resulting predictions of the scaling theory for the energy and residual shear stress. We also derive a scaling relation between pressure and residual shear stress that yields insight into why the shear and bulk moduli scale differently. Our theory shows that the jamming transition exhibits an emergent scale invariance, setting the stage for the potential development of a renormalization group theory for jamming.
48
Pouya, Amade, Cheng Zhu, and Chloé Arson. "Self-consistent micromechanical approach for damage accommodation in rock-like polycrystalline materials." International Journal of Damage Mechanics 28, no. 1 (December 12, 2017): 134–61. http://dx.doi.org/10.1177/1056789517747665.
Повний текст джерелаАнотація:
In quasi-brittle polycrystalline materials, damage by cracking or cleavage dominates plastic and viscous deformation. This paper proposes a micromechanical model for rock-like materials, incorporating the elastic-damage accommodation of the material matrix, and presents an original method to solve the system of implicit equations involved in the formulation. A self-consistent micromechanical approach is used to predict the anisotropic behavior of a polycrystal in which grain inclusions undergo intragranular damage. Crack propagation along planes of weakness with various orientation distributions at the mineral scale is modeled by a softening damage law and results in mechanical anisotropy at the macroscopic scale. One original aspect of the formulated inclusion–matrix model is the use of an explicit expression of Hill’s tensor to account for matrix ellipsoidal anisotropy. To illustrate the model capabilities, a uniaxial compression test was simulated for a variety of polycrystals made of two types of mineral inclusions with each containing only one plane of weakness. Damage always occurred in only one mineral type: the damaging mineral was that with a smaller shear modulus (respectively higher bulk modulus) when bulk modulus (respectively shear modulus) was the same. For two minerals with the same shear moduli but different bulk moduli, the maximum damage in the polycrystal under a given load was obtained at equal mineral fractions. However, for two minerals with different shear moduli, the macroscopic damage was not always maximum when the volume fraction of two minerals was the same. When the weakness planes’ orientations in the damaging mineral laid within a narrow interval close to the loading direction, the macroscopic damage behavior was more brittle than when the orientations were distributed over a wider interval. Parametric studies show that upon proper calibration, the proposed model can be extended to understand and predict the micro–macro behavior of different types of quasi-brittle materials.
49
Lee, Myung W. "A simple method of predicting S-wave velocity." GEOPHYSICS 71, no. 6 (November 2006): F161—F164. http://dx.doi.org/10.1190/1.2357833.
Повний текст джерелаАнотація:
Prediction of shear-wave velocity plays an important role in seismic modeling, amplitude analysis with offset, and other exploration applications. This paper presents a method for predicting S-wave velocity from the P-wave velocity on the basis of the moduli of dry rock. Elastic velocities of water-saturated sediments at low frequencies can be predicted from the moduli of dry rock by using Gassmann’s equation; hence, if the moduli of dry rock can be estimated from P-wave velocities, then S-wave velocities easily can be predicted from the moduli. Dry rock bulk modulus can be related to the shear modulus through a compaction constant. The numerical results indicate that the predicted S-wave velocities for consolidated and unconsolidated sediments agree well with measured velocities if differential pressure is greater than approximately [Formula: see text]. An advantage of this method is that there are no adjustable parameters to be chosen, such as the pore-aspect ratios required in some other methods. The predicted S-wave velocity depends only on the measured P-wave velocity and porosity.
50
Vatovec, Rok, Žiga Kozinc, and Matej Voglar. "The Effects of Isometric Fatigue on Trunk Muscle Stiffness: Implications for Shear-Wave Elastography Measurements." Sensors 22, no. 23 (December 4, 2022): 9476. http://dx.doi.org/10.3390/s22239476.
Повний текст джерелаАнотація:
Muscle stiffness has been implicated as a possible factor in low back pain risk. There are few studies on the effects of isometric fatigue on the shear modulus of trunk muscles. This study aimed to investigate the effects of trunk isometric fatigue on the passive and active (during low and high-level contractions) shear moduli of the erector spinae (ES) and superficial and deep multifidus (MF) muscles. We assessed passive and active shear modulus using shear-wave elastography in healthy young participants (n = 22; 11 males, 11 females), before and after an isometric trunk extension fatigue protocol. Maximal voluntary force decreased from 771.2 ± 249.8 N before fatigue to 707.3 ± 204.1 N after fatigue (−8.64%; p = 0.003). Passive shear modulus was significantly decreased after fatigue in the MF muscle (p = 0.006–0.022; Cohen’s d = 0.40–46), but not the ES muscle (p = 0.867). Active shear modulus during low-level contraction was not affected by fatigue (p = 0.697–0.701), while it was decreased during high-level contraction for both muscles (p = 0.011; d = 0.29–0.34). Sex-specific analysis indicated the decrease in ES shear modulus was significant in males (p = 0.015; d = 0.31), but not in females (p = 0.140). Conversely, the shear modulus in superficial MF had a statistically significant decrease in females (p = 0.002; d = 0.74) but not in males (p = 0.368). These results have important implications for further investigations of the mechanistic interaction between physical workloads, sex, muscle stiffness (and other variables affecting trunk stability and neuromuscular control), and the development/persistence of low back pain.