scholarly journals Rate of deformation in the cross section of a spatially curved rod with various assumptions

2021 ◽  
Vol 18 (3) ◽  
pp. 76-83
Author(s):  
Yu. L. Rutman ◽  
◽  
V. A. Meleshko ◽  
Keyword(s):  
Cross Section ◽  
Deformation Rate ◽  
Kinematic Parameters ◽  
Elastic Plastic ◽  
Tangential Stiffness ◽  
The Cross ◽  
Curved Rod

The article considers incremental relations connecting the changes in the kinematic parameters of the rod cross section with the deformation rate. These relations allow assessing the deformation rate on the elemental areas of a spatially curved rod, as well as considering the distortion of cross-section in its plane due to shear and torsion. Assessment of such relations between deformation rates and the rates of kinematic parameters allows developing the method of nonlinear calculation of rod systems based on integral expressions. Subsequently, these relations will be used for assessing the tangential stiffness of the rod element cross-section subjected to elastic-plastic calculation.

scholarly journals ПОЛНЫЕ ДИАГРАММЫ РАЗВИТИЯ ДЕСТРУКЦИЙ ОДНОРОДНО И НЕОДНОРОДНО СЖАТОГО БЕТОНА ПРИ ОСЕВОМ И ВНЕЦЕНТРЕННОМ НАГРУЖЕНИИ БЕТОННЫХ КОРОТКИХ КОЛОНН

2019 ◽  
Author(s):  
V. Sovgira ◽  
V. Sovgira
Keyword(s):  
Stress State ◽  
Cross Section ◽  
Concrete Columns ◽  
Load Level ◽  
Transverse Deformation ◽  
Plastic Properties ◽  
Elastic Plastic ◽  
Loading Mode ◽  
The Cross ◽  
Increasing Load

В статье приведены результаты выполненных исследований механизма интенсивности развития деструкций, псевдопластического деформирования и разрушения однородно и неоднородно сжатого тяжелого бетона призменной прочностью в диапазоне fc1522,265,6 МПа при мягком и жестком режиме нагружения одноосно и внецентренно сжатых бетонных колонн. Выполнен анализ литературных источников с исследованиями изменения упруго-пластических характеристик vc, Еcsek тяжелого бетона с учетом влияния значимых факторов и их изменение с увеличением уровня нагрузки при описании зависимости c-cх и c,е - cх,е. Установлено, что рекомендованные Строительными Нормами vcи и Ес одноосно сжатого бетона количественно и качественно не отражают характер изменения упруго-пластических свойств неоднородно сжатого бетона с ростом уровня нагрузки. Предложены аналитические выражения зависимости изменения коэффициентов упругости (vc, vc,е), секущих модулей упругости (Еcsek, Еc,еsek) и коэффициентов интенсивности развития деструкций (KD, KD,е) однородно и неоднородно сжатого бетона с ростом уровня нагрузки при мягком и жестком режиме нагружения исследованных серий тяжелого бетона с использованием сlx сlx,е Ес Nc,e/Ncu,e сu и сu,е, отражающих процесс изменения упруго-пластических свойств бетона на восходящих и нисходящих участках полных диаграмм деформирования бетона и их существенное отличие при центральном и внецентренном сжатии. Исследованиями отмечено, что интенсивность развития деструкций в структуре неоднородно нагруженного бетона существенно ниже, чем в одноосно сжатом. Экспериментами установлено характерное изменение по высоте сечения внецентренно сжатых бетонных элементов коэффициента поперечных деформаций , свидетельствующее о том, что с увеличением уровня нагрузки коэффициент наиболее сжатой фибры на всех уровнях нагрузки, значительно (в 1,21,5 раза) меньше волокон менее нагруженных фибр. Отмеченное свойство обусловлено изменением внутреннего напряженного состояния с ростом нагрузки и перераспределением напряжений силовыми связями структуры неоднородно сжатого бетона с субмикро- и микроуровней волокон наиболее нагруженной грани по высоте сечения внецентренно сжатых элементов на менее нагруженные волокна. Этот процесс перераспределения напряжений по высоте сечения бетонных колонн как свойство проявляется на изменении поперечной деформации cу,е и, как следствие изменения коэффициента поперечной деформации , влияющего на напряженное состояние сжатой зоны подобно внутренним силовым связям, обеспечивающим существенное повышение максимальных напряжений и деформаций в неоднородно сжатом бетоне.The article presents the results of studies of the intensity of development of destructions, pseudoplastic deformation and destruction of uniformly and non-uniformly compressed heavy concrete with prism strength in the range of fc1522,265,6 MPa in the soft and hard loading mode of uniaxially and eccentrically compressed concrete columns. The analysis of literary sources with studies of changes in the elastic-plastic characteristics of vc, Еcsek heavy concrete, taking into account the influence of significant factors and their change with increasing load level when describing the dependence c-cх and c,е - cх,е . It has been established that the vcu and Ес recommended by the Building Norms of uniaxially compressed concrete do not quantitatively and qualitatively reflect the nature of the change in the elastic-plastic properties of non-uniformly compressed concrete with increasing load levels. Analytical expressions are proposed for the dependence of the change in elasticity coefficients (vc, vc,е), cross-section elastic modulus (Еcsek, Еc,еsek) and the intensity factors for the development of destructions (KD, KD,е) of uniformly and non-uniformly compressed concrete and hard loading mode of the studied series of heavy concrete using: сlx сlx,е Ес Nc,e/Ncu,e сu and сu,е , reflecting the process of changing the elastic-plastic properties of concrete in the ascending and descending parts of the complete concrete deformation diagrams and their significant difference under uniaxial and eccentrically compression. Studies have noted that the intensity of the development of destructions in the structure of non-uniformly loaded concrete is significantly lower than in uniaxially compressed. Experiments established a characteristic change in the height of the cross section of eccentrically compressed concrete elements of the transverse strain coefficient , indicating that with an increase in the load level, the coefficient of the most compressed fiber at all load levels is significant (1,2-1,5 times) less fibers, less loaded fibers. This property is caused by the change in the internal stress state with increasing load and stress redistribution by force bonds of the structure in non-uniformly compressed concrete from submicro- and microlevels of the fibers of the most loaded face along the height of the cross section of eccentrically compressed elements to less loaded fibers. This process of stress redistribution along the height of the cross section of concrete columns as a property manifests itself in a change in transverse deformation cу,е and, as a result, a change in the transverse deformation coefficient , affecting the stress state of the compressed zone, similar to internal force connections, providing a significant increase in maximum stresses and strains in non-uniformly compressed concrete.

Effect of Temperature on Geometric Accuracy of AZ31 Profile during Warm Pre-Tension Rotation Bending

2011 ◽  
Vol 299-300 ◽  
pp. 432-435
Author(s):  
Han Xiao ◽  
Shi Hong Zhang ◽  
Jin Song Liu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Cross Section ◽  
Element Model ◽  
Effect Of Temperature ◽  
Geometric Accuracy ◽  
Elastic Plastic ◽  
Bending Process ◽  
Forming Temperature ◽  
The Cross

A warm pre-tension rotation bending process is presented to bend the AZ31 profile. A 3D elastic-plastic thermo-mechanical coupled finite element model is established to investigate the effect of forming temperature on the geometric accuracy of the profile. The results indicate that with increasing forming temperature, the springback angles decrease from 8.37° to 7.2°; the bending radii decrease from 90.69 mm to 89.67 mm; the cross-section distortion of the bent profile increases.

A New Approach to the Demonstration of Oxidase-Localization Using Tannic Acid Or Catechin

1973 ◽  
Vol 31 ◽  
pp. 698-699
Author(s):  
V. Mizuhira ◽  
Y. Futaesaku
Keyword(s):  
Cross Section ◽  
Tannic Acid ◽  
Elastic Fiber ◽  
The Other ◽  
New Approach ◽  
Tissue Block ◽  
Active Reaction ◽  
The Cross

Previously we reported that tannic acid is a very effective fixative for proteins including polypeptides. Especially, in the cross section of microtubules, thirteen submits in A-tubule and eleven in B-tubule could be observed very clearly. An elastic fiber could be demonstrated very clearly, as an electron opaque, homogeneous fiber. However, tannic acid did not penetrate into the deep portion of the tissue-block. So we tried Catechin. This shows almost the same chemical natures as that of proteins, as tannic acid. Moreover, we thought that catechin should have two active-reaction sites, one is phenol,and the other is catechole. Catechole site should react with osmium, to make Os- black. Phenol-site should react with peroxidase existing perhydroxide.

Energy Distribution in Electron Beams

1972 ◽  
Vol 30 ◽  
pp. 568-569
Author(s):  
Tamotsu Ohno
Keyword(s):  
Electron Beam ◽  
Energy Distribution ◽  
Cross Section ◽  
Integral Curve ◽  
Electron Beams ◽  
Electron Gun ◽  
Angular Divergence ◽  
Apparent Increase ◽  
Integral Width ◽  
The Cross

The energy distribution in an electron; beam from an electron gun provided with a biased Wehnelt cylinder was measured by a retarding potential analyser. All the measurements were carried out with a beam of small angular divergence (<3xl0-4 rad) to eliminate the apparent increase of energy width as pointed out by Ichinokawa.The cross section of the beam from a gun with a tungsten hairpin cathode varies as shown in Fig.1a with the bias voltage Vg. The central part of the beam was analysed. An example of the integral curve as well as the energy spectrum is shown in Fig.2. The integral width of the spectrum ΔEi varies with Vg as shown in Fig.1b The width ΔEi is smaller than the Maxwellian width near the cut-off. As |Vg| is decreased, ΔEi increases beyond the Maxwellian width, reaches a maximum and then decreases. Note that the cross section of the beam enlarges with decreasing |Vg|.

Research in the cross-section of community psychology and global climate change: A call for action

2009 ◽  
Author(s):  
Marci Culley ◽  
Holly Angelique ◽  
Courte Voorhees ◽  
Brian John Bishop ◽  
Peta Louise Dzidic ◽  
...  
Keyword(s):  
Climate Change ◽  
Cross Section ◽  
Global Climate Change ◽  
Community Psychology ◽  
Global Climate ◽  
The Cross

Experimental Studies Of Multilayer Glass Structures On Compression, Compression With Bending And Simple Bending

2019 ◽  
pp. 22-30
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Applied Load ◽  
Experimental Studies ◽  
Strength Properties ◽  
Research Topic ◽  
Normative Values ◽  
Laminated Glass ◽  
The Cross ◽  
Experimental Values

The work of multilayer glass structures for central and eccentric compression and bending are considered. The substantiation of the chosen research topic is made. The description and features of laminated glass for the structures investigated, their characteristics are presented. The analysis of the results obtained when testing for compression, compression with bending, simple bending of models of columns, beams, samples of laminated glass was made. Overview of the types and nature of destruction of the models are presented, diagrams of material operation are constructed, average values of the resistance of the cross-sections of samples are obtained, the table of destructive loads is generated. The need for development of a set of rules and guidelines for the design of glass structures, including laminated glass, for bearing elements, as well as standards for testing, rules for assessing the strength, stiffness, crack resistance and methods for determining the strength of control samples is emphasized. It is established that the strength properties of glass depend on the type of applied load and vary widely, and significantly lower than the corresponding normative values of the strength of heat-strengthened glass. The effect of the connecting polymeric material and manufacturing technology of laminated glass on the strength of the structure is also shown. The experimental values of the elastic modulus are different in different directions of the cross section and in the direction perpendicular to the glass layers are two times less than along the glass layers.

Seasonality in the Cross-Section of Stock Returns

CFA Digest ◽  
2008 ◽  
Vol 38 (3) ◽  
pp. 55-56
Author(s):  
Kathryn Dixon Jost
Keyword(s):  
Stock Returns ◽  
Cross Section ◽  
The Cross
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