scholarly journals NUMERICAL APPROACH FOR BENDING STRESS ASCERTAINMENT IN BEAM THEORY CONSIDERING EFFECTS OF ELASTIC SHEAR LAG

2017 ◽  
Vol 9 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Matthias KRAUS
Keyword(s):  
Cross Sections ◽  
Deformation Behaviour ◽  
Beam Theory ◽  
Numerical Approach ◽  
Bridge Engineering ◽  
Bending Moments ◽  
Normal Stresses ◽  
Plane State ◽  
Elastic Shear

In beam theory, normal stresses due to bending moments are usually determined with regard to Bernoullis hypothesis of the cross section staying in a plane state for reasons of simplicity. As a result of this fundamental assumption, the influence of shear on the distribution of normal stresses is not taken into account. However, for cross sections showing wide flanges, as they are commonly applied in bridge engineering for instance, the effect can usually not be disregarded. For the sake of capturing, stiffness oriented numerical approaches allowing the determination of the shear deformation behaviour of cross sections are applied and the shear influence is introduced into the normal stress calculation. This is being exemplarily shown for normal stresses due to bending moments M y.

scholarly journals The determination of normal stresses in cross-sections of the three-flue reinforced concrete chimney

2008 ◽  
Vol 3 (2) ◽  
pp. 081-095
Author(s):  
Małgorzata Dobrowolska ◽  
Marta Słowik
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Cross Sections ◽  
Analytical Form ◽  
Normal Stresses ◽  
Full Cross Section ◽  
Steel Bars ◽  
Reinforced Concrete Chimney ◽  
Physical Laws

In the paper there is presented the algorithm of calculation of normal stresses in reinforced concrete three-flue chimney. The calculation has been made for full cross-section and for cross-section weakened by openings. The governing equations has been derived in an analytical form assuming linear physical laws for concrete and steel and, as for as considered cross-section weakened by openings, taking into account the additional reinforcing steel bars at the openings. In addition coefficients B and C have been determined, which are useful at dimensioning.

Proposal for Calculations of Flat Oval Pipes Under Internal Pressure Under Consideration of Material Plastification

1997 ◽  
Vol 119 (3) ◽  
pp. 301-305
Author(s):  
J. Jekerle
Keyword(s):  
Yield Strength ◽  
Internal Pressure ◽  
Wall Thickness ◽  
Cross Sections ◽  
Calculation Method ◽  
Bending Moments ◽  
Normal Stresses ◽  
Shear Forces ◽  
Elastic Bending ◽  
Bending Stresses

In the wall of an oval pipe, additional to the circumferential forces, shear forces and bending moments occur under internal pressure load. Under this condition, the bending stresses in certain cross sections reach a figure many times that of normal stresses so that yield strength of the material can be exceeded. The usual stress calculation method is based on the calculation of the bending moments with the use of the elastic bending equation. The use of the part-plastic equation presented in the paper gives more accurate values for the bending moments sought in the cross sections being checked. This paper shows that even though the new calculation method leads to a smaller wall thickness of the flat oval pipe, the design of the flat oval pipe is nevertheless safe.

scholarly journals COMPOUND RUNS OF LOGS CALCULATION: ACCOUNTING OF LONGITUDINAL FORCES’ AND BENDING MOMENTS’ INTERACTION

2020 ◽  
Vol 17 (1) ◽  
pp. 136-149
Author(s):  
V. A. Utkin ◽  
P. N. Kobzev ◽  
E. G. Shatunova
Keyword(s):  
Classical Method ◽  
State Change ◽  
Bending Moments ◽  
Normal Stresses ◽  
Shear Forces ◽  
Load Bearing Capacity ◽  
Composite Girder ◽  
Financial Interest ◽  
Composite Girders

Introduction. Studying the designing and constructing experience of beam bridges with composite log girders indicates the possibility of the load bearing capacity rising of the structures and their further usage in the IV and V categories bridges’ construction under A-11 and H-11 loads. The purpose of the research is to evaluate the effect on the magnitude and distribution of shear forces in shear bonds, considering the permissible pliability of fixation in wood and on the nature of the stress state change in the rods of the composite girders.Materials and methods. The authors presented the construction of the composite girder in the form of three rows united by means of tie bolts and gaskets of four-tier single-row composite girders and made of edged logs. The proposed studying method of a composite girder stress-strain state with discrete placement of concentrated shear bonds in the joints based on the classical method of forces for rod systems, taking into account the interaction of longitudinal forces and bending moments arising in the rods composing the girder of unknown forces in the shear bonds.Results. The determination of single displacements with joint account of bending and stretching-compression deformations haв a significant impact on the redistribution of shear forces in the direction of increasing them in the support zones and reducing them in the middle of the span, and, consequently, on the design of the connecting elements. The character of distribution of normal stresses on the stretching-compression indicated the rods’ girders between relationships under the eccentric compression (stretching).Discussion and conclusions. The proposed solutions demonstrate the most accurate assessment of the composite girders in the structures of spans wooden bridges and present the application possibility in modern conditions.Financial transparency: the authors have no financial interest in the presented materials or methods. There is no conflict of interest.

Reduced-Order Modeling of Compressor Blades by 1D Finite Elements

2015 ◽  
Author(s):  
Luigi Carassale ◽  
Mirko Maurici ◽  
Laura Traversone
Keyword(s):  
Cross Sections ◽  
Gas Turbines ◽  
Beam Theory ◽  
Compressor Blade ◽  
Concept Design ◽  
Compressor Blades ◽  
Computational Tools ◽  
Reduced Order

The concept design of new gas turbines requires fast computational tools able to predict the modal characteristics of the blades on the basis of some incomplete description of their geometry. This paper investigates the potentials of a 1D Finite-Element (FE) formulation based on the beam theory to achieve this result. The key-point of the method is the construction of the FE mesh and the determination of the FE parameters starting from the knowledge of a set of blade cross sections. A typical compressor blade of a large gas turbine is used as a case study to validate the procedure.

Analysis of STEM micrographs of thick objects

1978 ◽  
Vol 36 (2) ◽  
pp. 106-107
Author(s):  
S. Golladay
Keyword(s):  
Inelastic Scattering ◽  
Multiple Scattering ◽  
Mass Distribution ◽  
Cross Sections ◽  
Phase Contrast ◽  
Image Point ◽  
Contrast Effects ◽  
Total Cross Sections ◽  
Elastic And Inelastic Scattering

The theory of multiple scattering has been worked out by Groves and comparisons have been made between predicted and observed signals for thick specimens observed in a STEM under conditions where phase contrast effects are unimportant. Independent measurements of the collection efficiencies of the two STEM detectors, calculations of the ratio σe/σi = R, where σe, σi are the total cross sections for elastic and inelastic scattering respectively, and a model of the unknown mass distribution are needed for these comparisons. In this paper an extension of this work will be described which allows the determination of the required efficiencies, R, and the unknown mass distribution from the data without additional measurements or models. Essential to the analysis is the fact that in a STEM two or more signal measurements can be made simultaneously at each image point.

A quantitative approach to inner shell losses

1978 ◽  
Vol 36 (1) ◽  
pp. 526-527 ◽  
Author(s):  
R.D. Leapman ◽  
P. Rez ◽  
D.F. Mayers
Keyword(s):  
Energy Transfer ◽  
Cross Section ◽  
Cross Sections ◽  
Accurate Determination ◽  
Background Intensity ◽  
Core Excitation ◽  
Quantitative Basis ◽  
Cross Section Differential ◽  
Bound Electrons

Microanalysis by EELS has been developing rapidly and though the general form of the spectrum is now understood there is a need to put the technique on a more quantitative basis (1,2). Certain aspects important for microanalysis include: (i) accurate determination of the partial cross sections, σx(α,ΔE) for core excitation when scattering lies inside collection angle a and energy range ΔE above the edge, (ii) behavior of the background intensity due to excitation of less strongly bound electrons, necessary for extrapolation beneath the signal of interest, (iii) departures from the simple hydrogenic K-edge seen in L and M losses, effecting σx and complicating microanalysis. Such problems might be approached empirically but here we describe how computation can elucidate the spectrum shape.The inelastic cross section differential with respect to energy transfer E and momentum transfer q for electrons of energy E0 and velocity v can be written as

Preparation And elemental analysis of ancient fibers

1987 ◽  
Vol 45 ◽  
pp. 410-411
Author(s):  
Allen Angel ◽  
Kathryn A. Jakes
Keyword(s):  
Cross Sections ◽  
Physical Structure ◽  
Energy Dispersive ◽  
Archaeological Sites ◽  
X Ray ◽  
Long Term Storage ◽  
Backscattered Electron ◽  
Electron Imaging

Fabrics recovered from archaeological sites often are so badly degraded that fiber identification based on physical morphology is difficult. Although diagenetic changes may be viewed as destructive to factors necessary for the discernment of fiber information, changes occurring during any stage of a fiber's lifetime leave a record within the fiber's chemical and physical structure. These alterations may offer valuable clues to understanding the conditions of the fiber's growth, fiber preparation and fabric processing technology and conditions of burial or long term storage (1).Energy dispersive spectrometry has been reported to be suitable for determination of mordant treatment on historic fibers (2,3) and has been used to characterize metal wrapping of combination yarns (4,5). In this study, a technique is developed which provides fractured cross sections of fibers for x-ray analysis and elemental mapping. In addition, backscattered electron imaging (BSI) and energy dispersive x-ray microanalysis (EDS) are utilized to correlate elements to their distribution in fibers.

Gender determination of caucasoid hair using image analysis

1993 ◽  
Vol 51 ◽  
pp. 216-217
Author(s):  
T.B. Ball ◽  
W.M. Hess
Keyword(s):  
Image Analysis ◽  
Cross Sections ◽  
Scalp Hair ◽  
The Body ◽  
Equivalent Diameter ◽  
Cross Sectional ◽  
Hair Samples ◽  
Length Width ◽  
Morphological Differences

It has been demonstrated that cross sections of bundles of hair can be effectively studied using image analysis. These studies can help to elucidate morphological differences of hair from one region of the body to another. The purpose of the present investigation was to use image analysis to determine whether morphological differences could be demonstrated between male and female human Caucasian terminal scalp hair.Hair samples were taken from the back of the head from 18 caucasoid males and 13 caucasoid females (Figs. 1-2). Bundles of 50 hairs were processed for cross-sectional examination and then analyzed using Prism Image Analysis software on a Macintosh llci computer. Twenty morphological parameters of size and shape were evaluated for each hair cross-section. The size parameters evaluated were area, convex area, perimeter, convex perimeter, length, breadth, fiber length, width, equivalent diameter, and inscribed radius. The shape parameters considered were formfactor, roundness, convexity, solidity, compactness, aspect ratio, elongation, curl, and fractal dimension.

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