Готові списки джерел за темами / Shear modulu

Добірка наукової літератури з теми "Shear modulu"

Автор: Grafiati
Опубліковано: 14 березня 2023

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Статті в журналах з теми "Shear modulu"

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.

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Анотація:
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.
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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.

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Анотація:
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.
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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.

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Анотація:
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.
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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.

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Анотація:
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.
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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.

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Анотація:
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.
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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.

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Анотація:
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.
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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.

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Анотація:
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.
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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.

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Анотація:
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.
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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.

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Анотація:
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.
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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.

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Анотація:
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.
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Більше джерел

Дисертації з теми "Shear modulu"

1

Pinilla, Camilo Ernesto. "Numerical simulation of shear instability in shallow shear flows." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=115697.

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The instabilities of shallow shear flows are analyzed to study exchanges processes across shear flows in inland and coastal waters, coastal and ocean currents, and winds across the thermal-and-moisture fronts. These shear flows observed in nature are driven by gravity and governed by the shallow water equations (SWE). A highly accurate, and robust, computational scheme has been developed to solve these SWE. Time integration of the SWE was carried out using the fourth-order Runge-Kutta scheme. A third-order upwind bias finite difference approximation known as QUICK (Quadratic Upstream Interpolation of Convective Kinematics) was employed for the spatial discretization. The numerical oscillations were controlled using flux limiters for Total Variation Diminishing (TVD). Direct numerical simulations (DNS) were conducted for the base flow with the TANH velocity profile, and the base flow in the form of a jet with the SECH velocity profile. The depth across the base flows was selected for the' balance of the driving forces. In the rotating flow simulation, the Coriolis force in the lateral direction was perfectly in balance with the pressure gradient across the shear flow during the simulation. The development of instabilities in the shear flows was considered for a range of convective Froude number, friction number, and Rossby number. The DNS of the SWE has produced linear results that are consistent with classical stability analyses based on the normal mode approach, and new results that had not been determined by the classical method. The formation of eddies, and the generation of shocklets subsequent to the linear instabilities were computed as part of the DNS. Without modelling the small scales, the simulation was able to produce the correct turbulent spreading rate in agreement with the experimental observations. The simulations have identified radiation damping, in addition to friction damping, as a primary factor of influence on the instability of the shear flows admissible to waves. A convective Froude number correlated the energy lost due to radiation damping. The friction number determined the energy lost due to friction. A significant fraction of available energy produced by the shear flow is lost due the radiation of waves at high convective Froude number. This radiation of gravity waves in shallow gravity-stratified shear flow, and its dependence on the convective Froude number, is shown to be analogous to the Mach-number effect in compressible flow. Furthermore, and most significantly, is the discovery from the simulation the crucial role of the radiation damping in the development of shear flows in the rotating earth. Rings and eddies were produced by the rotating-flow simulations in a range of Rossby numbers, as they were observed in the Gulf Stream of the Atlantic, Jet Stream in the atmosphere, and various fronts across currents in coastal waters.
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2

Harrison, S. Kate. "Comparison of Shear Modulus Test Methods." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/31772.

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Анотація:
This research compared the results of three tests: ASTM D 198 torsion, ASTM D 198 three-point bending and the five-point bending test (FPBT) using machine-stress-rated (MSR) lumber and laminated veneer lumber (LVL) to determine if the shear properties evaluated by the different test methods were equivalent. Measured E:G ratios were also compared to the E:G ratio of 16:1 commonly assumed for structural wooden members.

The average shear moduli results showed significant differences between the three test methods. For both material types, the shear moduli results determined from the two standard test methods (ASTM D 198 three-point bending and torsion), both of which are presently assumed to be equivalent, were significantly different.

Most average E:G ratios from the two material types and three test methods showed differences from the E:G ratio of 16:1 commonly assumed for structural wooden members. The average moduli of elasticity results for both material types were not significantly different. Therefore, the lack of significant difference between moduli of elasticity terms indicates that differences between E:G ratios are due to the shear modulus terms.

This research has shown differences in shear moduli results of the three test types (ASTM D 198 torsion, ASTM D 198 three-point bending, and the FPBT). Differences in the average E:G ratios per material and test type were also observed.
Master of Science

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3

Yung, See Yuen. "Determination of shear wave velocity and anisotropic shear modulus of an unsaturated soil /." View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?CIVL%202004%20YUNG.

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4

Guvenen, Haldun. "Aerodynamics of bodies in shear flow." Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184917.

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Анотація:
This dissertation investigates spanwise periodic shear flow past two-dimensional bodies. The flow is assumed to be inviscid and incompressible. Using singular perturbation techniques, the solution is developed for ε = L/ℓ ≪ 1, where L represents body cross-sectional size, and ℓ the period of the oncoming flow U(z). The singular perturbation analysis involves three regions: the inner, wake and outer regions. The leading order solutions are developed in all regions, and in the inner region higher order terms are obtained. In the inner region near the body, the primary flow (U₀, V₀, P₀) corresponds to potential flow past the body with a local free stream value of U(z). The spanwise variation in U(z) produces a weak O(ε) secondary flow W₁ in the spanwise direction. As the vortex lines of the upstream flow are convected downstream, they wrap around the body, producing significant streamwise vorticity in a wake region of thickness O(L) directly behind the body. This streamwise vorticity induces a net volume flux into the wake. In the outer region far from the body, a nonlifting body appears as a distribution of three-dimensional dipoles, and the wake appears as a sheet of mass sinks. Both singularity structures must be included in describing the leading outer flow. For lifting bodies, the body appears as a lifting line, and the wake appears as a sheet of shed vorticity. The trailing vorticity is found to be equal to the spanwise derivative of the product of the circulation and the oncoming flow. For lifting bodies the first higher order correction to the inner flow is the response of the body to the downwash produced by the trailing vorticity. At large distances from the body, the flow takes on remarkably simple form.
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5

Kinney, Landon Scott. "Pore Pressure Generation and Shear Modulus Degradation during Laminar Shear Box Testing with Prefabricated Vertical Drains." BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/7709.

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Анотація:
Liquefaction is a costly phenomenon where soil shear modulus degrades as the generation of excess pore pressures begins. One of the methods to mitigate liquefaction, is the use of prefabricated vertical drains. Prefabricated vertical drains provide a drainage path to effectively mitigate the generation of pore pressures and aid in shear modulus recovery. The aims of this study were to define shear modulus degradation vs. shear strain as a function of excess pore pressure ratio; define the effects of prefabricated vertical drains on the behavior of pore pressure generation vs. shear strain; and to define volumetric strain as a function of shear strain and excess pore pressure ratios. A large-scale laminar shear box test was conducted and measured on clean sands with prefabricated vertical drains spaced at 3-feet and 4-feet. The resulting test data was analyzed and compared to data without vertical drains. The results show the effect of increasing excess pore pressure ratios on shear modulus and curves where developed to encompass these effects in design with computer programing like SHAKE or DEEPSOIL. The data also suggests that prefabricated vertical drains effectively mitigate excess pore pressure build-up, thus increased the shear strain resistance before pore pressures were generated. Regarding volumetric strain, the results suggests that the primary factor governing the measured settlement is the excess pore pressure ratio. This indicates that if the drains can reduce the excess pore pressure ratio, then the resulting settlement can successfully be reduced during a shaking event. The curves for shear modulus vs. cyclic shear strain as function of pore pressure ratio were developed using data with high strain and small strain which leaves a gap of data in the cyclic shear strain range of 0.0001 to 0.01. Further large-scale testing with appropriate sensitivity is needed to observe the effect excess pore pressure generation on intermediate levels of cyclic shear strain.
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Olsen, Peter A. "Shear modulus degradation of liquefying sand : quantification and modeling /." Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2132.pdf.

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7

Olsen, Peter A. "Shear Modulus Degradation of Liquefying Sand: Quantification and Modeling." BYU ScholarsArchive, 2007. https://scholarsarchive.byu.edu/etd/1214.

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Анотація:
A major concern for geotechnical engineers is the ability to predict how a soil will react to large ground motions produced by earthquakes. Of all the different types of soil, liquefiable soils present some of the greatest challenges. The ability to quantify the degradation of a soil's shear modulus as it undergoes liquefaction would help engineers design more reliably and economically. This thesis uses ground motions recorded by an array of downhole accelerometers on Port Island, Japan, during the 1995 Kobe Earthquake, to quantify the shear modulus of sand as it liquefies. It has been shown that the shear modulus of sand decreases significantly as it liquefies, apparently decreasing in proportion to the increasing excess pore water pressure ratio (Ru). When completely liquefied, the shear modulus of sand (Ru = 1.0) for a relative density of 40 to 50% is approximately 15% of the high-strain modulus of the sand in its non-liquefied state, or 1% of its initial low-strain value. Presented in this thesis is an approach to modeling the shear modulus degradation of sand as it liquefies. This approach, called the "degrading shear modulus backbone curve method" reasonably predicts the hysteretic shear stress behavior of the liquefied sand. The shear stresses and ground accelerations computed using this method reasonably matches those recorded at the Port Island Downhole Array (PIDA) site. The degrading shear modulus backbone method is recommended as a possible method for conducting ground response analyses at sites with potentially liquefiable soils.
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8

Alathur, Srinivasan Prem Anand. "Deep Learning models for turbulent shear flow." Thesis, KTH, Numerisk analys, NA, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-229416.

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Анотація:
Deep neural networks trained with spatio-temporal evolution of a dynamical system may be regarded as an empirical alternative to conventional models using differential equations. In this thesis, such deep learning models are constructed for the problem of turbulent shear flow. However, as a first step, this modeling is restricted to a simplified low-dimensional representation of turbulence physics. The training datasets for the neural networks are obtained from a 9-dimensional model using Fourier modes proposed by Moehlis, Faisst, and Eckhardt [29] for sinusoidal shear flow. These modes were appropriately chosen to capture the turbulent structures in the near-wall region. The time series of the amplitudes of these modes fully describe the evolution of flow. Trained deep learning models are employed to predict these time series based on a short input seed. Two fundamentally different neural network architectures, namely multilayer perceptrons (MLP) and long short-term memory (LSTM) networks are quantitatively compared in this work. The assessment of these architectures is based on (i) the goodness of fit of their predictions to that of the 9-dimensional model, (ii) the ability of the predictions to capture the near-wall turbulence structures, and (iii) the statistical consistency of the predictions with the test data. LSTMs are observed to make predictions with an error that is around 4 orders of magnitude lower than that of the MLP. Furthermore, the flow fields constructed from the LSTM predictions are remarkably accurate in their statistical behavior. In particular, deviations of 0:45 % and 2:49 % between the true data and the LSTM predictions were obtained for the mean flow and the streamwise velocity fluctuations, respectively.
Djupa neuronät som är tränade med rum-tids utveckling av ett dynamiskt system kan betraktas som ett empiriskt alternativ till konventionella modeller som använder differentialekvationer. I denna avhandling konstruerar vi sådana djupinlärningsmodeller för att modellera en förenklad lågdimensionell representation av turbulensfysiken. Träningsdata för neuronäten erhålls från en 9-dimensionell modell (Moehlis, Faisst och Eckhardt [29]) för olika Fourier-moder i ett skärskikt. Dessa moder har ändamålsenligt valts för att avbilda de turbulenta strukturerna i regionen nära väggen. Amplitudernas tidsserier för dessa moder beskriver fullständigt flödesutvecklingen, och tränade djupinlärningsmodeller används för att förutsäga dessa tidsserier baserat på en kort indatasekvens. Två fundamentalt olika neuronätsarkitekturer, nämligen flerlagerperceptroner (MLP) och långa närminnesnätverk (LSTM), jämförs kvantitativt i denna avhandling. Utvärderingen av dessa arkitekturer är baserad på (i) hur väl deras förutsägelser presterar jämfört med den 9-dimensionella modellen, (ii) förutsägelsernas förmåga att avbilda turbulensstrukturerna nära väggar och (iii) den statistiska överensstämmelsen mellan nätverkets förutsägelser och testdatan. Det visas att LSTM gör förutsägelser med ett fel på ungefär fyra storleksordningar lägre än för MLP. Vidare, är strömningsfälten som är konstruerade från LSTM-förutsägelser anmärkningsvärt noggranna i deras statistiska beteende. I synnerhet uppmättes avvikelser mellan de sanna- och förutsagda värdena för det genomsnittliga flödet till 0; 45 %, och för de strömvisa hastighetsfluktionerna till 2; 49 %.
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9

Raischel, Frank. "Fibre models for shear failure and plasticity." [S.l. : s.n.], 2007. http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-29619.

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10

Rara, Angela Dominique Sarmiento. "Rolling Shear Strength and Modulus for Various Southeastern US Wood Species using the Two-Plate Shear Test." Thesis, Virginia Tech, 2021. http://hdl.handle.net/10919/104017.

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Cross-Laminated Timber (CLT) is an engineered wood product made by laminating dimensional or structural composite lumber in alternating orthogonal layers. Compared to Canada and Europe, CLT is a novel product to the US. With the additions included in the 2021 International Building Code (IBC), CLT material properties, especially rolling shear, would need to be explored. The increasing demand for softwood lumber, along with the increase of demand of CLT panel production, could place a burden and surpass the domestic softwood supply. Rolling shear is a phenomenon that occurs when the wood fibers in the cross-layers roll over each other because of the shearing forces acting upon a CLT panel when it is loaded out-of-plane. This study used the two-plate shear test from ASTM D2718 to measure the rolling shear properties of various southeastern US wood species: southern pine, yellow-poplar, and soft maple. A secondary study was conducted, using the same two-plate shear test, to measure the rolling shear properties of re-manufactured southern pine for CLT cross-layer application. The soft maple had the greatest average rolling shear strength at 5.93 N/mm2 and southern pine had the lowest average rolling shear strength at 2.51 N/mm2. Using a single factor analysis of variance (ANOVA), the rolling shear strength values from soft maple were significantly greater than yellow-poplar, which was significantly greater than the southern pine. For the rolling shear modulus, the southern pine and soft maple were of equal statistically significant difference, and both were greater statistically significant different compared to the yellow-poplar. The most common failure found from testing was rolling shear.
Master of Science
Cross-Laminated Timber (CLT) is an engineered wood panel product, similar to plywood, constructed with solid-sawn or structural composite lumber in alternating perpendicular layers. The additions included in the incoming 2021 International Building Code (IBC) has placed an importance in expanding the research related to the mechanical and material properties of CLT. Also, with the increasing demand for softwood lumber and CLT panel production, the demand for the domestic softwood lumber could place a burden and surpass the domestic softwood supply. Rolling shear is a failure type that occurs when the wood fibers in the cross-layers roll over each other because of the shearing forces acting upon a CLT panel. This study used the two-plate shear test to measure the rolling shear properties of various southeastern US wood species: southern pine, yellow-poplar, and soft maple. A secondary study was conducted, using the same two-plate shear test, to measure the rolling shear properties of re-manufactured southern pine for CLT cross-layer application. The soft maple had the greatest average rolling shear strength at 5.93 N/mm2 and southern pine had the lowest average rolling shear strength at 2.51 N/mm2. Using a single factor analysis of variance (ANOVA), the rolling shear strength values from soft maple were significantly greater than yellow-poplar, which was significantly greater than the southern pine. For the rolling shear modulus, the southern pine and soft maple were of equal statistically significant difference, and both were greater statistically significant different compared to the yellow-poplar. The most common failure found from testing was rolling shear.
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Книги з теми "Shear modulu"

1

Statens råd för byggnadsforskning (Sweden), ed. Analysis of shear walls. Stockholm: Swedish Council for Building Research, 1985.

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2

Trevino, G. Structure of wind-shear turbulence. Hampton, Va: Langley Research Center, 1989.

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3

R, Laituri Tony, and United States. National Aeronautics and Space Administration. Scientific and Technical Information Division., eds. Structure of wind-shear turbulence. [Washington, DC]: National Aeronautics and Space Administration, Scientific and Technical Information Division, 1989.

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4

R, Laituri Tony, and United States. National Aeronautics and Space Administration., eds. Structure of wind-shear turbulence. [Washington, DC]: [National Aeronautics and Space Administration, 1988.

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5

R, Laituri Tony, and United States. National Aeronautics and Space Administration., eds. Structure of wind-shear turbulence. [Washington, DC]: [National Aeronautics and Space Administration, 1988.

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6

R, Laituri Tony, and United States. National Aeronautics and Space Administration. Scientific and Technical Information Division., eds. Structure of wind-shear turbulence. [Washington, DC]: National Aeronautics and Space Administration, Scientific and Technical Information Division, 1989.

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7

S, Sarkar, and Langley Research Center, eds. Second-order closure models for supersonic turbulent flows. Hampton, Va: National Aeronautics and Space Administration, Langley Research Center, 1991.

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8

S, Sarkar, and Langley Research Center, eds. Second-order closure models for supersonic turbulent flows. Hampton, Va: National Aeronautics and Space Administration, Langley Research Center, 1991.

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9

B, Gatski T., Fitzmaurice N. 1959-, and Langley Research Center, eds. An analysis of RNG based turbulence models for homogeneous shear flow. Hampton, Va: National Aeronautics and Space Administration, Langley Research Center, 1991.

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10

Tzuoo, K. L. Zonal models of turbulence and their application to free shear flows. Stanford, Calif: Thermosciences Division, Dept. of Mechanical Engineering, Stanford University, 1986.

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Частини книг з теми "Shear modulu"

1

Keaton, Jeffrey R. "Shear Modulus." In Selective Neck Dissection for Oral Cancer, 1–2. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-12127-7_256-1.

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2

Gooch, Jan W. "Shear Modulus." In Encyclopedic Dictionary of Polymers, 657. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_10529.

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3

Keaton, Jeffrey R. "Shear Modulus." In Encyclopedia of Earth Sciences Series, 830–31. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-73568-9_256.

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4

Gooch, Jan W. "Complex Shear Modulus." In Encyclopedic Dictionary of Polymers, 161. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_2737.

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Gooch, Jan W. "Modulus in Shear." In Encyclopedic Dictionary of Polymers, 467. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_7588.

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6

Borghi, R., and E. Pourbaix. "Lagrangian Models for Turbulent Combustion." In Turbulent Shear Flows 4, 369–80. Berlin, Heidelberg: Springer Berlin Heidelberg, 1985. http://dx.doi.org/10.1007/978-3-642-69996-2_30.

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7

Chen, J. Y., and W. Kollmann. "Mixing Models for Turbulent Flows with Exothermic Reactions." In Turbulent Shear Flows 7, 277–92. Berlin, Heidelberg: Springer Berlin Heidelberg, 1991. http://dx.doi.org/10.1007/978-3-642-76087-7_21.

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8

Hanjalić, Kemal, and Slavko Vasić. "Some Further Exploration of Turbulence Models for Buoyancy Driven Flows." In Turbulent Shear Flows 8, 319–41. Berlin, Heidelberg: Springer Berlin Heidelberg, 1993. http://dx.doi.org/10.1007/978-3-642-77674-8_23.

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9

Sawaguchi, Takahiro. "Designing High-Mn Steels." In The Plaston Concept, 237–57. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-7715-1_11.

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AbstractHigh-Mn austenitic steels undergo characteristic plasticity mechanisms of the γ-austenite with an FCC structure, such as extended dislocation glide, mechanical twinning, and mechanical martensitic transformation into ε-martensite with an HCP structure and/or α’-martensite with a BCC/BCT structure. Distortions of polyhedron models are used to describe these plasticity mechanisms. These are the smallest volumetric units occupying the lattices and reflect the crystallographic characteristics of the lattices. The complicated crossing shears are correlated to the fine crystal phases formed at the intersection of the ε-martensite variants. The unidirectionality of the {1 1 1} < 1 1 2 > γ twinning shear provides reversibility to the dislocation motion under cyclic loading. Based on this knowledge, the design concept of high-Mn steels is described considering microstructural, thermodynamic, and crystallographic characteristics.
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10

Summerscales, John. "Shear Modulus Testing of Composites." In Composite Structures 4, 305–16. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-009-3457-3_23.

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Тези доповідей конференцій з теми "Shear modulu"

1

Arlt, Rainer. "Magnetic shear-flows in stars." In MHD COUETTE FLOWS: Experiments and Models. AIP, 2004. http://dx.doi.org/10.1063/1.1832148.

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2

COUSTOLS, E. "Behaviour of internal manipulators - 'Riblet' models in subsonic andtransonic flows." In 2nd Shear Flow Conference. Reston, Virigina: American Institute of Aeronautics and Astronautics, 1989. http://dx.doi.org/10.2514/6.1989-963.

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3

Zaqarashvili, T. V. "Instability of periodic MHD shear flows." In MHD COUETTE FLOWS: Experiments and Models. AIP, 2004. http://dx.doi.org/10.1063/1.1832149.

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4

PENHA FARIA, RENATO, and Luiz Nunes. "STUDY OF EFFECTIVE SHEAR MODULUS ON FLEXIBLE COMPOSITES UNDER SIMPLE SHEAR." In 25th International Congress of Mechanical Engineering. ABCM, 2019. http://dx.doi.org/10.26678/abcm.cobem2019.cob2019-0561.

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5

Weaver, John B., Timothy B. Miller, Marvin D. Doyley, Huifang Wang, Phillip R. Perrinez, Yvonne Y. Cheung, Francis E. Kennedy, and Keith D. Paulsen. "Reproducibility of MRE shear modulus estimates." In Medical Imaging, edited by Armando Manduca and Xiaoping P. Hu. SPIE, 2007. http://dx.doi.org/10.1117/12.713772.

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6

Han, De‐hua, and Michael Batzle. "Estimate shear velocity based on dry P‐wave and shear modulus relationship." In SEG Technical Program Expanded Abstracts 2004. Society of Exploration Geophysicists, 2004. http://dx.doi.org/10.1190/1.1845148.

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7

Ju, Jaehyung, Joshua D. Summers, John Ziegert, and George Fadel. "Compliant Hexagonal Meso-Structures Having Both High Shear Strength and High Shear Strain." In ASME 2010 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/detc2010-28672.

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Motivated by the authors’ previous study on flexible honeycomb design with negative Poisson’s ratio (NPR) often called ‘auxetic’ [1], more geometric options of hexagonal honeycomb meso-structures are explored with various ratios of the vertical cell length, h to the inclined length, l. While designing an effective shear modulus, e.g., G12* of 10MPa, of hexagonal honeycombs, we are searching honeycomb geometries. Using an aluminum alloy (7075-T6) as the constituent material, the in-plane linear elastic honeycomb model is employed to get effective shear moduli, effective shear yield strengths and effective shear yield strains of hexagonal honeycombs. The numerical parametric study based on the linear cellular theory is combined with honeycomb design to get the optimal cell geometry associated with a manufacturing limitation. The re-entrant geometry makes 7075-T6 NPR honeycombs flexible, resulting in an effective shear yield strength, (τpl*)12 of 1.7MPa and an effective shear yield strain, (γpl*)12 of 0.17 when they are designed to have a G12* of 10MPa.
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8

Villacreses, Juan, and Bernardo Caicedo. "A comparison between Shear Modulus Degradation Curves." In The 5th World Congress on Civil, Structural, and Environmental Engineering. Avestia Publishing, 2020. http://dx.doi.org/10.11159/icgre20.131.

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9

Salavatian, M., and L. V. Smith. "Shear Modulus Degradation in Fiber Reinforced Laminates." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-63035.

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Matrix damage, involving transverse and shear cracks, is a common failure mode for composite structures, yet little is known concerning their interaction. A modified Iosipescu coupon is proposed to study the evolution of the shear and transverse damage and their mutual effects. The layup and coupon geometry were selected in a way that controls the severity of the damage and allows the measurement of shear and transverse stiffness degradation directly. The results were compared to material degradation models where damage was dominated by matrix failure. While positive agreement was generally observed in the transverse direction, no model was able to predict the observed shear damage. A new elasticity solution was, therefore, proposed for the shear stress-strain field of a transversely cracked laminate. The approach used a classical shear lag theory with friction applied to the crack surfaces. Using the constitutive relations, the shear modulus reduction was found as a function of crack density, and showed good agreement with experimental measures.
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10

K. Sinha, Bikash, Badarinadh Vissapragada, Lasse Renlie, and Sveinung Tysse. "Radial profiling of three formation shear moduli." In SEG Technical Program Expanded Abstracts 2005. Society of Exploration Geophysicists, 2005. http://dx.doi.org/10.1190/1.2144343.

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Звіти організацій з теми "Shear modulu"

1

Kinikles, Dellena, and John McCartney. Hyperbolic Hydro-mechanical Model for Seismic Compression Prediction of Unsaturated Soils in the Funicular Regime. Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, December 2022. http://dx.doi.org/10.55461/yunw7668.

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A semi-empirical elasto-plastic constitutive model with a hyperbolic stress-strain curve was developed with the goal of predicting the seismic compression of unsaturated sands in the funicular regime of the soil-water retention curve (SWRC) during undrained cyclic shearing. Using a flow rule derived from energy considerations, the evolution in plastic volumetric strain (seismic compression) was predicted from the plastic shear strains of the hysteretic hyperbolic stress-strain curve. The plastic volumetric strains are used to predict the changes in degree of saturation from phase relationships and changes in pore air pressure from Boyle’s and Henry’s laws. The degree of saturation was used to estimate changes in matric suction from the transient scanning paths of the SWRC. Changes in small-strain shear modulus estimated from changes in mean effective stress computed from the constant total stress and changes in pore air pressure, degree of saturation and matric suction, in turn affect the hyperbolic stress-strain curve’s shape and the evolution in plastic volumetric strain. The model was calibrated using experimental shear stress-strain backbone curves from drained cyclic simple shear tests and transient SWRC scanning path measurements from undrained cyclic simple shear tests. Then the model predictions were validated using experimental data from undrained cyclic simple shear tests on unsaturated sand specimens with different initial degrees of saturation in the funicular regime. While the model captured the coupled evolution in hydro-mechanical variables (pore air pressure, pore water pressure, matric suction, degree of saturation, volumetric strain, effective stress, shear modulus) well over the first 15 cycles of shearing, the predictions were less accurate after continued cyclic shearing up to 200 cycles. After large numbers of cycles of undrained shearing, a linear decreasing trend between seismic compression and initial degree of saturation was predicted from the model while a nonlinear increasing-decreasing trend was observed in the cyclic simple shear experiments. This discrepancy may be due to not considering post shearing reconsolidation in the model, calibration of model parameters, or experimental issues including a drift in the position of the hysteretic shear-stress strain curve. Nonetheless, the trend from the model is consistent with predictions from previously- developed empirical models in the funicular regime of the SWRC. The developments of the new mechanistic model developed in this study will play a key role in the future development of a holistic model for predicting the seismic compression across all regimes of the SWRC.
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2

Adolf, D., C. Childress, and D. Hannum. Bulk and shear moduli of epoxy encapsulants. Office of Scientific and Technical Information (OSTI), August 1989. http://dx.doi.org/10.2172/5524601.

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3

Canfield, Thomas R. Calculations using density dependent melt temperature and shear modulus with the PTW strength model (u). Office of Scientific and Technical Information (OSTI), September 2011. http://dx.doi.org/10.2172/1078436.

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4

Becker, R. Tantalum Shear Modulus from Homogenization of Single Crystal Data. Office of Scientific and Technical Information (OSTI), September 2007. http://dx.doi.org/10.2172/925669.

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5

Swift, D. Analytic fits to atom-in-jellium shear modulus predictions. Office of Scientific and Technical Information (OSTI), September 2020. http://dx.doi.org/10.2172/1660525.

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6

Wright, T. W., and H. Ockendon. A Model For Fully Formed Shear Bands. Fort Belvoir, VA: Defense Technical Information Center, August 1992. http://dx.doi.org/10.21236/ada254713.

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7

Preston, Dean Laverne, Leonid Burakovsky, Sky K. Sjue, and Diane Elizabeth Vaughan. IC W15_thermoelasticity Highlight: Shear modulus and melting curve of Be. Office of Scientific and Technical Information (OSTI), December 2016. http://dx.doi.org/10.2172/1337134.

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8

Spang, M. C., T. B. Casper, and K. I. Thomassen. Model development for transport studies in negative shear modes. Office of Scientific and Technical Information (OSTI), May 1997. http://dx.doi.org/10.2172/598539.

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Ulitsky, M. A Proper Method for Introducing Shear into Compressible RANS Models. Office of Scientific and Technical Information (OSTI), July 2014. http://dx.doi.org/10.2172/1150036.

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10

Chang, Y. W., and R. W. Seidensticker. Dynamic characteristics of Bridgestone low shear modulus-high damping seismic isolation bearings. Office of Scientific and Technical Information (OSTI), June 1993. http://dx.doi.org/10.2172/10181217.

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