The Elastic Moduli of Heterogeneous Materials

1962 ◽  
Vol 29 (1) ◽  
pp. 143-150 ◽  
Author(s):  
Zvi Hashin
Keyword(s):  
Approximate Method ◽  
Elastic Moduli ◽  
Heterogeneous Materials ◽  
Theory Of Elasticity ◽  
Experimental Results ◽  
Two Phase ◽  
Concentric Spheres ◽  
Theoretical Results ◽  
Nonhomogeneous Materials ◽  
Good Agreement

Bounds and expressions for the elastic moduli of two or many phase nonhomogeneous materials are obtained by an approximate method based on the variational theorems of the theory of elasticity and on a concentric-spheres model. Theoretical results are in good agreement with experimental results for a two-phase alloy.

A Stochastic Nonlinear Constitutive Law for Concrete

1989 ◽  
Vol 111 (4) ◽  
pp. 443-449 ◽  
Author(s):  
A. Fafitis ◽  
Y. H. Won
Keyword(s):  
Stochastic Model ◽  
Elastic Moduli ◽  
Three Dimensional ◽  
Path Dependency ◽  
Experimental Results ◽  
Constitutive Law ◽  
Induced Anisotropy ◽  
Nonproportional Loading ◽  
Strain Relationship ◽  
Good Agreement

An incremental three-dimensional stress-strain relationship for concrete with induced anisotropy has been developed. The nonlinearity and path-dependency are modeled by expressing the elastic moduli at each increment as function of the octahedral and deviatoric strains, based on a uniaxial stochastic model developed earlier. Predictions of multiaxial response under proportional and nonproportional loading are in good agreement with experimental results.

New Design Formula for Bolted Joints Under Tensile Loads

2013 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Yuya Omiya
Keyword(s):  
Tensile Load ◽  
Theoretical Background ◽  
Theory Of Elasticity ◽  
Experimental Results ◽  
Spring Constant ◽  
Load Factor ◽  
Outer Diameter ◽  
Hollow Cylinders ◽  
The Difference ◽  
Good Agreement

In designing a bolted joint, it is important to estimate an increment in axial bolt force when an external tensile load is applied to an assembly. The ratio of the increment Ft in the axial bolt force to the external tensile load W is called the load factor φ(= Ft/w). The formula φ = Kt/(Kt+Kc) proposed by Thum has been applied for estimating the value of the load factor φ, where Kt is the spring constant of bolt-nut system and Kc is the compressive spring constant of clamped parts. It has been found that the value of the load factor varies with the position of load application to the assembly. Then, a method to compensate Thum’s formula was proposed. However, this compensation is made empirically and the theoretical background is not made clear. In this paper, the concept of the tensile spring constant Kpt for clamped parts is introduced newly when an external load is applied to the outer circumference of clamped parts (hollow cylinders) and a method for estimating the value of the load factor exactly is proposed by using Kpt. The value of Kpt is analyzed using an axisymmetric theory of elasticity. For verification of the proposed method, experiments were carried out to measure the load factor. A fairly good agreement is seen between the analytical and the experimental results of the values of the load factor while the values of the load factor obtained from Thum’s formula were so different with the experimental results. The reason why the difference in the values of the load factor is substantial between values and the values obtained from Thum’s formula is elucidated. It is found that the value of the load factor decreases as the outer diameter of the hollow cylinder increases and the as thickness of the clamped parts decreases. In addition, FEM calculations for the load factor are carried out. The FEM results are in a fairly good agreement with the theoretical results.

Pressure Broadening of the Microwave Absorption Lines of Oxygen

1973 ◽  
Vol 51 (22) ◽  
pp. 2329-2331 ◽  
Author(s):  
Y. Yamamoto ◽  
M. Cattani
Keyword(s):  
Microwave Absorption ◽  
Quadrupole Moment ◽  
Microwave Spectrum ◽  
The Self ◽  
Experimental Results ◽  
Dispersion Interactions ◽  
Pressure Broadening ◽  
Line Widths ◽  
Theoretical Results ◽  
Good Agreement

We calculate the line widths for the self-broadening of the microwave spectrum of oxygen taking into account simultaneously quadrupole–quadrupole and dispersion interactions. Our theoretical results are compared with the more recent experimental results. A good agreement is obtained between them if the oxygen quadrupole moment is taken as Q = 1.21 ± 0.05 D Å.

Surface Roughness Effects in High-Speed Hydrodynamic Journal Bearings

1997 ◽  
Vol 119 (4) ◽  
pp. 776-780 ◽  
Author(s):  
H. Hashimoto
Keyword(s):  
Surface Roughness ◽  
High Speed ◽  
Reynolds Equation ◽  
Computation Time ◽  
Experimental Results ◽  
Roughness Effects ◽  
Modified Reynolds Equation ◽  
Nonlinear Simultaneous Equations ◽  
Theoretical Results ◽  
Good Agreement

This paper describes an applicability of modified Reynolds equation considering the combined effects of turbulence and surface roughness, which was derived by Hashimoto and Wada (1989), to high-speed journal bearing analysis by comparing the theoretical results with experimental ones. In the numerical analysis of modified Reynolds equation, the nonlinear simultaneous equations for the turbulent correction coefficients are greatly simplified to save computation time with a satisfactory accuracy under the assumption that the shear flow is superior to the pressure flow in the lubricant films. The numerical results of Sommerfeld number and attitude angle are compared with the experimental results to confirm the applicability of the modified Reynolds equation in the case of two types of bearings with different relative roughness heights. Good agreement was obtained between theoretical and experimental results.

Two-Phase Flow-Induced Forces on Bends in Small Scale Tubes

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
M. F. Cargnelutti ◽  
S. P. C. Belfroid ◽  
W. Schiferli
Keyword(s):  
Experimental Data ◽  
Structural Integrity ◽  
Two Phase Flow ◽  
Experimental Results ◽  
Small Scale ◽  
Phase Flow ◽  
Momentum Exchange ◽  
Two Phase ◽  
Worst Case ◽  
Good Agreement

Two-phase flow occurs in many situations in industry. Under certain circumstances, it can be a source of flow-induced vibrations. The forces generated can be sufficiently large to affect the performance or efficiency of an industrial device. In the worst-case scenario, the mechanical forces that arise may endanger structural integrity. Thus, it is important to take these forces into account in designing industrial machinery to avoid problems during operation. Although the occurrence of such forces is well known, not much is known about their magnitudes because, unfortunately, the amount of experimental data available in literature are rather limited. This paper describes the experiments performed to measure forces in 6 mm diameter tubing containing a bend. Experiments are performed on bends of different radii, with the bend positioned horizontally or vertically. The experimental results are analyzed based on flow regime and bend configuration. A comparison with available experimental results for bigger internal pipe diameter shows a general good agreement. To improve future predictions, a simple model based on momentum exchange is proposed to estimate the forces generated by multiphase flow. The proposed model shows a good agreement with the experimental data.

scholarly journals Theoretical and Experimental Study of Optimization of Polarization Spectroscopy for the D2 Closed Transition Line of 87Rb Atoms

2021 ◽  
Vol 11 (16) ◽  
pp. 7219
Author(s):  
Jeongyoun Jeong ◽  
Sanglok Lee ◽  
Sungi Hwang ◽  
Jaeuk Baek ◽  
Heung-Ryoul Noh ◽  
...  
Keyword(s):  
Pump Beam ◽  
Experimental Results ◽  
Transition Line ◽  
Matrix Equations ◽  
Optimal Parameters ◽  
Cell Temperature ◽  
Vapor Cell ◽  
Polarization Spectroscopy ◽  
Theoretical Results ◽  
Good Agreement

We experimentally and theoretically investigated the optimal condition of polarization spectroscopy for frequency stabilization on various pump beam intensities and vapor cell temperatures for the D2 closed transition line of 87Rb atoms. We compared the experimental results, such as the amplitude, width, and slope, of the polarization spectroscopy signal with the theoretical results obtained from the numerical calculation of temporal density matrix equations. Based on the results, we found the optimal parameters, such as the pump beam intensity and vapor cell temperature, for polarization spectroscopy. The theoretically expected optimal parameters were, qualitatively, in good agreement with the experimental results.

scholarly journals NUMERICAL SIMULATIONS FOR NON CONSERVATIVE HYPERBOLIC SYSTEM. APPLICATION TO TRANSIENT TWO-PHASE FLOW WITH CAVITATION PHENOMENON

2019 ◽  
Vol 24 (2) ◽  
pp. 218-235
Author(s):  
Abdelmjid Qadi El Idrissi ◽  
Boujemâa Achchab ◽  
Abdellatif Agouzal
Keyword(s):  
Numerical Technique ◽  
Liquid Mixtures ◽  
Dissolved Gas ◽  
Two Phase ◽  
Gas Concentration ◽  
Transient Flows ◽  
Cavitation Phenomenon ◽  
The Mathematical Model ◽  
Theoretical Results ◽  
Good Agreement

A numerical method for simulating transient flows of gas-liquid mixtures is proposed. The mathematical model, established for a suspension of gas bubbles in liquid, includes an equation taking into account the relative velocity between the gas and liquid. A numerical technique based on the Mac Cormack scheme combined with the method of characteristics is presented. Theoretical results for transients initiated by a rapid closing valves are compared with measurements. A good agreement is found particularly for large values of initial dissolved gas concentration.

INVESTIGATION OF THE ENTROPY AND SPECIFIC HEAT CAPACITY OF GaN USING INCOMPLETE GAMMA FUNCTIONS

2008 ◽  
Vol 22 (30) ◽  
pp. 5349-5355 ◽  
Author(s):  
SAVAŞ SÖNMEZOǦLU
Keyword(s):  
Heat Capacity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Experimental Results ◽  
Analytical Relation ◽  
Gamma Functions ◽  
Temperature Range ◽  
Incomplete Gamma Functions ◽  
Theoretical Results ◽  
Good Agreement

The aim of this paper is to provide validity and reliable analytical relation for the thermodynamic functions calculated in terms of the Debye temperature using incomplete gamma functions, and examines the entropy and specific heat capacity of hexagonal single crystals of GaN in the 0–1800 K temperature range. The obtained results have been compared with the corresponding experimental and theoretical results. Our results are in excellent agreement with the theoretical results over the entire temperature range. It has also shown that at low temperature, our results are in very good agreement with the experimental results, however, at high temperature, our results are lower than other experimental results.

A NOVEL MODEL OF DIELECTRIC CONSTANT OF TWO-PHASE COMPOSITES WITH INTERFACIAL SHELLS

2002 ◽  
Vol 16 (25) ◽  
pp. 3855-3863 ◽  
Author(s):  
QINGZHONG XUE
Keyword(s):  
Dielectric Constant ◽  
Effective Dielectric Constant ◽  
Maxwell Theory ◽  
Two Phase ◽  
Random Composites ◽  
Polarization Theory ◽  
Two Phases ◽  
Novel Model ◽  
Theoretical Results ◽  
Good Agreement

Considering the interface effect between two phases in composite, we present a novel model of dielectric constant of two-phase composites with interfacial shells. Starting from Maxwell theory and average polarization theory, the formula of calculating the effective dielectric constant of two-phase random composites with interfacial shells is presented. The theoretical results on effective dielectric constant of alkyd resin paint/Barium titanate random composites with interfacial shells are in good agreement with the experimental data.

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