Deflection and Stresses in Beams Subjected to Bending and Creep

1952 ◽  
Vol 19 (4) ◽  
pp. 478-484
Author(s):  
Yoh-Han Pao ◽  
Joseph Marin
Keyword(s):  
Stress Distribution ◽  
Pure Bending ◽  
Stress Variation ◽  
Creep Stress ◽  
Simple Tension ◽  
Hardening Theory ◽  
Time Relation ◽  
Theoretical Results ◽  
Good Agreement

Abstract This paper presents theories for the determination of deflections and stresses in beams subjected to bending and creep. The theories are based on a creep-stress-time relation in simple tension which gives an accurate fit of most test data. The theory takes into account the variation in stress distribution in bending with time. For this purpose a time-hardening theory is used to express the stress variation or stress relaxation of each fiber in bending. A comparison between actual creep deflections for Plexiglas specimens subjected to pure bending and values predicted by the proposed theory shows good agreement between experimental and theoretical results. The creep behavior for other materials in tension indicates that this method could be used for predicting bending creep deflections for these materials. The application of the theory to the determination of deflections in various kinds of beams is also explained.

Shape of a Wire in a Centrifugal Field—Application to Quasi-Circular Bare Filament Flywheels

1983 ◽  
Vol 105 (2) ◽  
pp. 221-226 ◽  
Author(s):  
G. Genta
Keyword(s):  
Numerical Calculation ◽  
Stress Distribution ◽  
Numerical Integration ◽  
Equilibrium Equation ◽  
Series Solution ◽  
Field Application ◽  
Centrifugal Field ◽  
Low Speed ◽  
Theoretical Results ◽  
Good Agreement

In order to calculate the stress distribution in bare filament rotors it is necessary to evaluate with good approximation the shape taken by the wires in the centrifugal field (sometimes referred to as “polar catenary”). This problem is usually solved via a numerical integration of the equilibrium equation of the wire. In this paper a series solution of the same equilibrium equation is obtained. The calculation of the stress distribution in the rotor, which is an interative one and requires the evaluation of the shape of each wire several times, becomes faster and can be performed also in those conditions in which the numerical calculation failed (i.e., at low speed, when the “subcircularity” of the wires is too great to be taken into account in that way). Photographic and photoelastic tests are in good agreement with theoretical results.

scholarly journals Theory determination of $$\varvec{\bar{B}\rightarrow D^{(*)}\ell ^-\bar{\nu }}$$ form factors at $$\varvec{\mathcal {O}(1/m_c^2)}$$

2020 ◽  
Vol 80 (2) ◽  
Author(s):  
Marzia Bordone ◽  
Martin Jung ◽  
Danny van Dyk
Keyword(s):  
Experimental Data ◽  
Light Cone ◽  
Sum Rules ◽  
Form Factors ◽  
Longitudinal Polarization ◽  
Polarization Fraction ◽  
Theoretical Results ◽  
Good Agreement ◽  
Lepton Flavour

Abstract We carry out an analysis of the full set of ten $$\bar{B}\rightarrow D^{(*)}$$B¯→D(∗) form factors within the framework of the Heavy-Quark Expansion (HQE) to order $$\mathcal {O}\left( \alpha _s,\,1/m_b,\,1/m_c^2\right) $$Oαs,1/mb,1/mc2, both with and without the use of experimental data. This becomes possible due to a recent calculation of these form factors at and beyond the maximal physical recoil using QCD light-cone sum rules, in combination with constraints from lattice QCD, QCD three-point sum rules and unitarity. We find good agreement amongst the various theoretical results, as well as between the theoretical results and the kinematical distributions in $$\bar{B}\rightarrow D^{(*)}\lbrace e^-,\mu ^-\rbrace \bar{\nu }$$B¯→D(∗){e-,μ-}ν¯ measurements. The coefficients entering at the $$1/m_c^2$$1/mc2 level are found to be of $$\mathcal {O}(1)$$O(1), indicating convergence of the HQE. The phenomenological implications of our study include an updated exclusive determination of $$|V_{cb}|$$|Vcb| in the HQE, which is compatible with both the exclusive determination using the BGL parametrization and with the inclusive determination. We also revisit predictions for the lepton-flavour universality ratios $$R_{D^{(*)}}$$RD(∗), the $$\tau $$τ polarization observables $$P_\tau ^{D^{(*)}}$$PτD(∗), and the longitudinal polarization fraction $$F_L$$FL. Posterior samples for the HQE parameters are provided as ancillary files, allowing for their use in subsequent studies.

Laminar Free Convection From a Downward-Projecting Fin

1968 ◽  
Vol 90 (1) ◽  
pp. 63-70 ◽  
Author(s):  
G. S. H. Lock ◽  
J. C. Gunn
Keyword(s):  
Boundary Layer ◽  
Free Convection ◽  
Prandtl Number ◽  
Experimental Program ◽  
Boundary Layer Problem ◽  
Theoretical Predictions ◽  
Theoretical Results ◽  
Good Agreement ◽  
Quiescent Fluid

A theoretical analysis of conduction through and free convection from a tapered, downward-projecting fin immersed in an isothermal quiescent fluid is presented. The problem is solved by assuming quasi-one-dimensional heat conduction in the fin and matching the solution to that of the convection system, which is treated as a boundary layer problem. For an infinite Prandtl number, solutions are derived which take the form of a power law temperature distribution along the fin. The effect of this power (n) on heat transfer, drag, and the corresponding boundary layer profiles is discussed. It is shown that n is independent of the fin profile and dependent on a single nondimensional group χ. The theoretical results for infinite Prandtl number are compared with corresponding results derived from previous work using a Prandtl number of unity. The effect of Prandtl number on the determination of n and consequently the fin effectiveness is found to be extremely small. The results of an experimental program are also presented. These consist of temperature profiles and the n — χ relation for different fin geometries and surrounding fluids. Comparison with the theoretical predictions reveals good agreement.

scholarly journals Determination of effective atomic numbers and electron densities from mass attenuation coefficients for some selected complexes containing lanthanides

2017 ◽  
Vol 95 (10) ◽  
pp. 1005-1011 ◽  
Author(s):  
Ferdi Akman ◽  
Mustafa Recep Kaçal ◽  
Feride Akman ◽  
Mustafa Serkan Soylu
Keyword(s):  
Chemical Parameters ◽  
Electron Densities ◽  
Attenuation Coefficients ◽  
Transmission Geometry ◽  
Mass Attenuation Coefficients ◽  
Effective Atomic Numbers ◽  
Theoretical Results ◽  
Good Agreement ◽  
Mass Attenuation

The effective atomic numbers and electron densities for the pure elemental forms of gadolinium (Gd), dysprosium (Dy), erbium (Er), and ytterbium (Yb), and some of their selected complexes, were obtained from the measured total mass attenuation coefficients at 13.92, 17.75, 20.78, 26.34, and 59.54 keV photon energies using a high-resolution Si(Li) detector by adopting transmission geometry. The measured results were compared with two different theoretical results. Within experimental deviations, our data are in good agreement with the theoretical values. The obtained parameters were also interpreted with some selected chemical parameters.

scholarly journals Theoretical and experimental determination of mass attenuation coefficients of lead-based ceramics and their comparison with simulation

2016 ◽  
Vol 31 (2) ◽  
pp. 142-149 ◽  
Author(s):  
Alireza Vejdani-Noghreiyan ◽  
Elham Aliakbari ◽  
Atiyeh Ebrahimi-Khankook ◽  
Mahdi Ghasemifard
Keyword(s):  
Gamma Ray ◽  
Mass Attenuation Coefficient ◽  
X Ray Diffraction ◽  
Attenuation Coefficients ◽  
X Ray ◽  
Simulation Results ◽  
Theoretical Results ◽  
Good Agreement ◽  
Mass Attenuation

Mass attenuation coefficient of lead-based ceramics have been measured by experimental methods and compared with theoretical and Monte Carlo simulation results. Lead-based ceramics were prepared using mixed oxide method and the X-ray diffraction analysis was done to evaluate the crystal structure of the produced handmade ceramics. The experimental results show good agreement with theoretical and simulation results. However at two gamma ray energies, small differences between experimental and theoretical results have been observed. By adding other additives to ceramics and observing the changes in the shielding properties such as flexibility, one can synthesize and optimize ceramics as a neutron shield.

Neurospectral modeling of rectangular patch with rectangular aperture in the ground plane

2014 ◽  
Vol 7 (6) ◽  
pp. 759-768 ◽  
Author(s):  
Lotfi Djouane ◽  
Sami Bedra ◽  
Randa Bedra ◽  
Tarek Fortaki
Keyword(s):  
Ground Plane ◽  
Accurate Determination ◽  
Rectangular Aperture ◽  
Rectangular Patch ◽  
Spectral Domain Approach ◽  
Performances Evaluation ◽  
Half Power ◽  
Theoretical Results ◽  
Good Agreement

In this study, we propose an artificial neural network in conjunction with spectral domain approach (SDA), for fast and accurate determination of the resonant frequency and half-power bandwidth of rectangular patch over the ground plane with rectangular aperture. The performances evaluation of the neurospectral method reveals superiority over the conventional SDA model in terms of errors and time. The results obtained from the neurospectral method are in very good agreement with the experimental and theoretical results available in the literature. Finally, numerical results for the effect of rectangular aperture dimensions on the resonant characteristics of the rectangular patch are also investigated.

Stress distribution in a sharp-edged wedge under boundary conditions similar to those of wedge indentation

1981 ◽  
Vol 16 (1) ◽  
pp. 15-28
Author(s):  
M I Ghobrial ◽  
P R Lancaster ◽  
P B Mellor
Keyword(s):  
Stress Distribution ◽  
Boundary Conditions ◽  
Contact Length ◽  
Tangential Stresses ◽  
Wedge Indentation ◽  
Rigid Material ◽  
Theoretical Results ◽  
Good Agreement ◽  
Distributed Pressure

Plasticity analysis for orthogonal indentation of plastic rigid material by an acute angled wedge suggests that the faces of the wedge will be subjected to uniformly distributed pressure and tangential stresses over the contact length. In the present work the stress distribution at the tip of an infinitely deep wedges obtained when the wedge is subjected to such a stress distribution. The theoretical results are compared with photoelastic experiments and good agreement is achieved.

Investigating the Nonlinear Optical Response of Pepper Oil under Low Power Irradiation with Continuous Wave Visible Laser Beam

2020 ◽  
pp. 131-138
Keyword(s):  
Refractive Index ◽  
Nonlinear Refractive Index ◽  
Nonlinear Optical ◽  
Continuous Wave ◽  
Diffraction Integral ◽  
Visible Laser ◽  
Limiting Property ◽  
Kirchhoff Diffraction Integral ◽  
Theoretical Results ◽  
Good Agreement

The nonlinear optical properties of pepper oil are studied by diffraction ring patterns and Z-scan techniques with continuous wave beam from solid state laser at 473 nm wavelength. The nonlinear refractive index of the sample is calculated by both techniques. The sample show high nonlinear refractive index. Based on Fresnel-Kirchhoff diffraction integral, the far-field intensity distributions of ring patterns have been calculated. It is found that the experimental results are in good agreement with the theoretical results. Also the optical limiting property of pepper oil is reported. The results obtained in this study prove that the pepper oil has applications in nonlinear optical devices.

COMPARATIVE ACTION OF VARIOUS OESTROGENIC COMPOUNDS ON MOUSE VAGINAL SIALIC ACIDS (II)

1969 ◽  
Vol 62 (4) ◽  
pp. 663-670 ◽  
Author(s):  
Lars Carlborg
Keyword(s):  
Sialic Acid ◽  
Response Curve ◽  
Sialic Acids ◽  
Clear Cut ◽  
Suitable Parameter ◽  
Sufficient Degree ◽  
Comparative Action ◽  
Relative Potencies ◽  
Good Agreement

ABSTRACT Oestrogens administered in lower doses than necessary to induce full cornification of the mouse vagina induce mucification. It was shown previously that the degree of mucification could be estimated by quantitative determination of sialic acids. A suitable parameter for oestrogen assay was the measurement of vaginal sialic acid concentration which exhibited a clear cut dose response curve. Eleven assays of various oestrogens were performed with this method. Their estimated relative potencies were in good agreement with other routine oestrogen assays. A statistically sufficient degree of precision was found. The sensitivity was of the same order, or slightly higher, than the Allen-Doisy test.

An Automated Method for the Determination of Serum Calcium with Glyoxal Bis (2-Hydroxyanil)

1967 ◽  
Vol 13 (6) ◽  
pp. 515-520 ◽  
Author(s):  
Genevieve Farese ◽  
Janice L Schmidt ◽  
Milton Mager
Keyword(s):  
Serum Calcium ◽  
Automated Analysis ◽  
Automated Method ◽  
Good Agreement

Abstract A completely automated analysis is described for the determination of serum calcium with glyoxal bis (2-hydroxyanil) solution (GBHA). The method is simple and precise, and the data obtained are in good agreement with results obtained by the manual GBHA procedure.

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