scholarly journals Generalized Softened Variable Angle Truss Model for RC Hollow Beams under Torsion

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2209
Author(s):  
Luís Bernardo
Keyword(s):  
Solution Procedure ◽  
Pure Torsion ◽  
Specific Behavior ◽  
Torsional Response ◽  
Truss Model ◽  
Variable Angle ◽  
Theoretical Predictions ◽  
Hollow Beams ◽  
Theoretical Results ◽  
Good Agreement

In recent studies, a new softened truss model called Generalized Softened Variable Angle Truss Model (GSVATM) has been proposed to compute the full torsional response of reinforced concrete (RC) rectangular solid beams under pure torsion. In this article, the GSVATM is extended to cover RC hollow beams under torsion. The modification of the calculation procedure, in order to account for the specific behavior of RC hollow beams for low loading levels, as well as the final solution procedure, is presented. The theoretical predictions from the extended GSVATM are compared with experimental results of RC hollow beams under torsion found in the literature. Good agreement is observed between the experimental and theoretical results, for both high and low loading levels.

Modified rotating-angle softened truss model for composite box-girder with corrugated steel webs under pure torsion

2020 ◽  
Vol 23 (9) ◽  
pp. 1902-1921 ◽  
Author(s):  
Yingbo Zhu ◽  
Shui Wan ◽  
Kongjian Shen ◽  
Qiang Su ◽  
Xiayuan Li
Keyword(s):  
Torsional Stiffness ◽  
Pure Torsion ◽  
Torsional Deformation ◽  
Box Girder ◽  
Torsional Response ◽  
Truss Model ◽  
Strain Relationship ◽  
Corrugated Steel Web ◽  
Accuracy Of Prediction ◽  
Good Agreement

Replacement of traditional concrete webs with corrugated steel webs will lead to a significant decrease in torsional stiffness of composite box-girder with corrugated steel webs, which needs special attention in the design of wide and curved composite box-girder with corrugated steel webs. To improve the accuracy of prediction on the entire torsional performance of composite box-girder with corrugated steel webs, a modified rotating-angle softened truss model for torsion is developed in this study. Modified rotating-angle softened truss model for torsion mainly takes into account the new three-stage average stress coefficients, the new two-stage shear strain relationship between corrugated steel web and slabs, and the torsional deformation coordination of whole cross section. To testify the accuracy of modified rotating-angle softened truss model for torsion and to better understand the performance of composite box-girder with corrugated steel webs under pure torsion, two scaled specimens are tested in this article. The torque–twist curves and shear strains calculated by modified rotating-angle softened truss model for torsion reach a good agreement with experimental results, which indicates that modified rotating-angle softened truss model for torsion can successfully predict the entire torsional performance of composite box-girder with corrugated steel webs. In addition, compared with test data obtained from previous literature, the proposed modified rotating-angle softened truss model for torsion is more capable of predicting full torsional response of composite box-girder with corrugated steel webs than other rotating-angle models, especially at cracking stage and ultimate stage.

scholarly journals Softened Truss Model for Reinforced Concrete Beams under Torsion Combined with Axial Force

2020 ◽  
Vol 1 (1) ◽  
pp. 79-96 ◽  
Author(s):  
Luís Bernardo ◽  
Cátia Taborda
Keyword(s):  
Reinforced Concrete ◽  
Prestressed Concrete ◽  
Concrete Beams ◽  
Solution Procedure ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Axial Forces ◽  
Truss Model ◽  
Theoretical Predictions ◽  
Good Agreement

The Generalized Softened Variable Angle Truss Model (GSVATM) allows one to compute the global behavior of reinforced concrete (RC) beams under torsion, including the pre- and post-cracking stage. In a previous study, such a model was successfully extended to cover prestressed concrete beams under torsion with longitudinal and uniform prestress. In order to continue to extend the theoretical model for other loading cases, in this article, the GSVATM is extended to cover RC beams under torsion combined with external and centered axial forces. The changes in GSVATM are presented, as well as the modified calculation solution procedure. Some theoretical predictions from the extended GSVATM are compared with numerical results from the non-linear finite element method (FEM), where good agreement is observed for the studied trends.

Thermal Behavior and Friction in Journal Bearings

1970 ◽  
Vol 92 (3) ◽  
pp. 373-380 ◽  
Author(s):  
Al. Nica
Keyword(s):  
Experimental Data ◽  
Thermal Behavior ◽  
Heat Dissipation ◽  
Journal Bearings ◽  
Friction Torque ◽  
Operating Characteristics ◽  
Lubricant Flow ◽  
Theoretical Predictions ◽  
Theoretical Results ◽  
Good Agreement

This paper deals with friction and the field of temperature in the lubricant film of journal bearings. Theoretical results regarding the thermal behavior are checked with experimental data and good agreement is found. Emphasis is put on the variation of temperature and lubricant flow with the operating characteristics of the bearing and it is seen that theoretical predictions for minima of friction torque are backed by temperature measurements. Further on, the friction torque and the mechanism of heat dissipation in bearings are dealt with, in order to verify the assumptions used in the calculation schemes. The means of efficiently cooling the bearing are also discussed, as well as the part played by the divergent zone in this process.

Beam-foil spectroscopy of oxygen in the wavelength region from 270 to 490 Å

1978 ◽  
Vol 56 (5) ◽  
pp. 508-516 ◽  
Author(s):  
Eric H. Pinnington ◽  
Keith E. Donnelly ◽  
J. Anthony Kernahan ◽  
David J. G. Irwin
Keyword(s):  
Satisfactory Agreement ◽  
Wavelength Region ◽  
Theoretical Predictions ◽  
The Mean ◽  
Theoretical Results ◽  
Beam Foil ◽  
Foil Technique ◽  
Good Agreement

We have used the beam-foil technique to study the spectrum of oxygen between 270 and 490 Å. We have measured the mean lives of the 3d2F, 3d4P, 3d4D, 3d′ 2D, 3d′ 2F, 4d4P, and 4d4D terms of O II, the 3s1P0, 3s3P0, 3S5P, 3s′ 3D, 3d3P, 3d3D, 3d3F, and 3d5P terms of O III, and the 3S2S, 3P2P0, and 3s4P0 terms of O IV. All cascade components are adequately explained. Good agreement is found with previous measurements in most cases, but significant discrepancies are found with some earlier results obtained using branches above 2000 Å. Generally satisfactory agreement is also found with theoretical predictions, although disagreement is found for several members of the 2p3–2p23d array in O II f-Values are computed for 18 individual lines, and compared with other experimental and theoretical results. Finally, we discuss briefly the f-value trends along the 2p23P–2p3s3P0 (O III), 2p21D–2p3s1P0 (O III), 2s2p24P–2s2p(3P0)3s4P0 (O IV), and 2p2P0–3s2S (O IV) isoelectronic sequences.

scholarly journals Softened Variable Angle Truss Model (RA-STM): Model Description and Refinement/Optimization Proposals

2020 ◽  
Author(s):  
Benedito Filho ◽  
Luís Bernardo ◽  
Bernardo Horowitz
Keyword(s):  
Pure Shear ◽  
Solution Procedure ◽  
Experimental Results ◽  
Model Description ◽  
Structural Concrete ◽  
Truss Model ◽  
Variable Angle ◽  
Computational Implementation ◽  
Concrete Plates

This article presents a recent softened truss model with variable angle, namely the refined RA-STM (Rotating-Angle Softened Truss Model), to model the behaviour of structural concrete plates under pure shear.  The equations of the model, as well as the solution procedure, are summarized. Some predictions from the RA-STM are also presented, discussed and compared with experimental results available in the literature. It is shown that the refined RA-STM still needs to be refined. In addition, the need to generalize the RA-STM for more general loading cases is also discussed as well as the need to optimize the solution procedure in order to facilitate its computational implementation.

Comparison Between Theoretical Predictions of Wave Resistance and Experimental Data for the Wigley Hull

1983 ◽  
Vol 27 (04) ◽  
pp. 215-226
Author(s):  
C. Y. Chen ◽  
F. Noblesse
Keyword(s):  
Experimental Data ◽  
Froude Number ◽  
Resistance Coefficient ◽  
Wave Resistance ◽  
Number Range ◽  
Theoretical Predictions ◽  
Wigley Hull ◽  
Sinkage And Trim ◽  
Theoretical Results ◽  
Good Agreement

A number of theoretical predictions of the wave-resistance coefficient of the Wigley hull are compared with one another and with available experimental data, to which corrections for sinkage and trim are applied. The averages of eleven sets of experimental data (corrected for sinkage and trim) and of eleven sets of theoretical results for large values of the Froude number, specifically for F 0.266, 0.313, 0.350, 0.402, 0.452, and 0.482, are found to be in fairly good agreement, in spite of considerable scatter in both the experimental data and the numerical results. Furthermore, several sets of theoretical results are fairly close to the average experimental data and the average theoretical predictions for these large values of the Froude number. Discrepancies between theoretical predictions and experimental measurements for small values of the Froude number, specifically for F = 0.18, 0.20, 0.22, 0.24, and 0.266, generally are much larger than for the above-defined high-Froude-number range. However, a notable exception to this general finding is provided by the first-order slender-ship approximation evaluated in Chen and Noblesse [1],3 which is in fairly good agreement with the average experimental data over the entire range of values of Froude number considered in this study.

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 The κ-statistics approach to epidemiology

2020 ◽  
Author(s):  
Giorgio Kaniadakis ◽  
Mauro M. Baldi ◽  
Thomas S. Deisboeck ◽  
Giulia Grisolia ◽  
Dionissios T. Hristopulos ◽  
...  
Keyword(s):  
Theoretical Model ◽  
Statistical Approach ◽  
Weibull Model ◽  
Distribution Functions ◽  
Statistical Distributions ◽  
Systematic Analysis ◽  
Epidemiological Analysis ◽  
Theoretical Predictions ◽  
Theoretical Results ◽  
Good Agreement

Abstract A great variety of complex physical, natural and artificial systems are governed by statistical distributions, which often follow a standard exponential function in the bulk, while their tail obeys the Pareto power law. The recently introduced κ-statistics framework predicts distribution functions with this feature. A growing number of applications in different fields of investigation are beginning to prove the relevance and effectiveness of κ-statistics in fitting empirical data. In this paper, we use κ-statistics to formulate a statistical approach for epidemiological analysis. We validate the theoretical results by fitting the derived κ-Weibull distributions with data from the plague pandemic of 1417 in Florence as well as data from the COVID-19 pandemic in China over the entire cycle that concludes in April 16, 2020. As further validation of the proposed approach we present a more systematic analysis of COVID-19 data from countries such as Germany, Italy, Spain and United Kingdom, obtaining very good agreement between theoretical predictions and empirical observations. For these countries we also study the entire first cycle of the pandemic which extends until the end of July 2020. The fact that both the data of the Florence plague and those of the Covid-19 pandemic are successfully described by the same theoretical model, even though the two events are caused by different diseases and they are separated by more than 600 years, is evidence that the κ-Weibull model has universal features.

scholarly journals The κ-statistics approach to epidemiology

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Giorgio Kaniadakis ◽  
Mauro M. Baldi ◽  
Thomas S. Deisboeck ◽  
Giulia Grisolia ◽  
Dionissios T. Hristopulos ◽  
...  
Keyword(s):  
Theoretical Model ◽  
Statistical Approach ◽  
Weibull Model ◽  
Distribution Functions ◽  
Statistical Distributions ◽  
Systematic Analysis ◽  
Epidemiological Analysis ◽  
Theoretical Predictions ◽  
Theoretical Results ◽  
Good Agreement

AbstractA great variety of complex physical, natural and artificial systems are governed by statistical distributions, which often follow a standard exponential function in the bulk, while their tail obeys the Pareto power law. The recently introduced $$\kappa $$ κ -statistics framework predicts distribution functions with this feature. A growing number of applications in different fields of investigation are beginning to prove the relevance and effectiveness of $$\kappa $$ κ -statistics in fitting empirical data. In this paper, we use $$\kappa $$ κ -statistics to formulate a statistical approach for epidemiological analysis. We validate the theoretical results by fitting the derived $$\kappa $$ κ -Weibull distributions with data from the plague pandemic of 1417 in Florence as well as data from the COVID-19 pandemic in China over the entire cycle that concludes in April 16, 2020. As further validation of the proposed approach we present a more systematic analysis of COVID-19 data from countries such as Germany, Italy, Spain and United Kingdom, obtaining very good agreement between theoretical predictions and empirical observations. For these countries we also study the entire first cycle of the pandemic which extends until the end of July 2020. The fact that both the data of the Florence plague and those of the Covid-19 pandemic are successfully described by the same theoretical model, even though the two events are caused by different diseases and they are separated by more than 600 years, is evidence that the $$\kappa $$ κ -Weibull model has universal features.

scholarly journals Elasto-capillary coalescence of multiple parallel sheets

2013 ◽  
Vol 723 ◽  
pp. 692-705 ◽  
Author(s):  
A. D. Gat ◽  
M. Gharib
Keyword(s):  
Energy Analysis ◽  
Minimal Energy ◽  
Common Assumption ◽  
Viscous Forces ◽  
Theoretical Predictions ◽  
The Mean ◽  
The Stability ◽  
Elastic Sheets ◽  
Theoretical Results ◽  
Good Agreement

AbstractWe analyse two-dimensional clamped parallel elastic sheets which are partially immersed in liquid as a model for elasto-capillary coalescence. In the existing literature this problem is studied via minimal energy analysis of capillary and elastic energies of the post-coalescence state, yielding the maximal stable post-coalescence bundle size. Utilizing modal stability analysis and asymptotic analysis, we studied the stability of the configuration before the coalescence occurred. Our analysis revealed previously unreported relations between viscous forces, body forces, and the instability yielding the coalescence, thus undermining a common assumption that coalescence will occur as long as it will not create a bundle larger than the maximal stable post-coalesced size. A mathematical description of the process creating the hierarchical coalescence structure was obtained and yielded that the mean number of sheets per coalesced region is limited to the subset ${2}^{N} $ where $N$ is the set of natural numbers. Our theoretical results were illustrated by experiments and good agreement with the theoretical predictions was observed.

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