Study of the Stress-Strain State (SSS) and the Type of Stress State of a Model Closed Wing of an Airplane by the Using Speckle Interferometry

At the present time the assessment of stress-strain state of steel structures uses the results of coercive measurements. However, the methods presented in various works are contradictory and not deprived of errors of a methodological nature, which may lead to erroneous conclusions. This article reveals the analysis of disadvantages of the known methods and proposes possible ways to eliminate these shortcomings.

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The stress-strain state of the foundation of various forms using the Kelvin equation

10.35688/2413-8452-2015-04-001 ◽

2015 ◽

Vol 4 ◽

pp. 4-6

Author(s):

Pilyagin A.V.

Keyword(s):

Stress State ◽

Strain State ◽

Ground Surface ◽

Deep Foundations ◽

Natural Basis ◽

Stress Strain ◽

Concentrated Force ◽

Kelvin Equation ◽

Large Depth ◽

Stress Strain State

The article discusses the stress-strain state of Foundation of various forms. It is noted that for foundations on natural basis is traditionally used for the solution of Boussinesq (1885) about the force applied to the ground surface, i.сe. without taking into account the fact that the depth of the foundations, and the solution obtained Mindlin (1950) takes into account the fact that the depth of foundations, but does not consider the development of tensile stresses above the level of application of the load. The analysis of the Kelvin equation for concentrated force applied at an infinitely large depth. The analysis of the stress state of grounds for the buried foundations using solution of Kelvin indicates the possibility of its use in the case of the use of deep foundations.

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DYNAMIC COMPRESSIBILITY OF BIRCH AT DIFFERENT TYPES OF STRESS-STRAINED STATE

Problems of Strength and Plasticity ◽

10.32326/1814-9146-2020-82-3-269-282 ◽

2020 ◽

Vol 82 (3) ◽

pp. 269-282

Author(s):

A.M. Bragov ◽

A.K. Lomunov ◽

T.N. Yuzhina

Keyword(s):

Stress State ◽

Strain State ◽

Uniaxial Stress ◽

Deformation Condition ◽

Dynamic Tests ◽

Stress Strain ◽

Free Expansion ◽

Noticeable Increase ◽

Stress Strain State ◽

Deformation Diagrams

The results of dynamic tests for compression across the fibers at room temperature of birch samples with air humidity are presented. Dynamic tests were carried out on a setup with a split Hopkinson bar according to the Kolsky method at a strain rate of ~2000 s–1. To assess the effect of the type of stress-strain state on the behavior of the material, in addition to specimens in the form of cylinders with its free expansion during loading (uniaxial stress state condition), specimens were tested in a rigid casing that prevents the radial expansion of the specimen (uniaxial deformation condition), as well as local compressive tests of rectangular board fragments. In the latter case, the material surrounding the loading zone plays the role of a compliant confining casing. In this case, a certain intermediate stress-strain state is realized in the sample. For these three types of stress-strain state, dynamic deformation diagrams were obtained with registration of additional loading cycles. Comparison of obtained deformation diagrams shows a significant effect of the type of stress-strain state on the behavior of the material under study. In the case of free expansion of the specimen in the radial direction, the absence of strain hardening is observed in the first loading cycle. In subsequent cycles, hardening is negligible. The deformation diagrams of specimens in the casing as well as board fragments are characterized by a noticeable increase in the modulus of the hardening branch with increasing deformation. In this case, it can be noted that the behavior of the material in the case of testing a piece of board is intermediate between the cases of uniaxial stress state and uniaxial strain state. Some mechanical characteristics of the material are determined using the diagrams obtained. The obtained experimental results can serve as the basis for the subsequent identification of the model of deformation and destruction of wood.

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Indentation of the cylindrical shell in the elastoplastic half-space

Multiphase Systems ◽

10.21662/mfs2018.3.007 ◽

2018 ◽

Vol 13 (3) ◽

pp. 47-51

Author(s):

A.A. Filippov

Keyword(s):

Cylindrical Shell ◽

Stress State ◽

Half Space ◽

Safety Factor ◽

Strain State ◽

Fracture Criterion ◽

Steel Shell ◽

Stress Strain ◽

Stress Strain State ◽

Steel Cylindrical Shell

The article deals with the problem of pressing the steel cylindrical shell into the elastoplastic half-space having a cylindrical concavity. The calculation and analysis of the stress-strain state of the steel shell and elastoplastic half-space. Given the dependence of the shear half-space, the safety factor and stress state in steel shell from the force pushing the shell in the half-space. The calculations were carried out for three radii of concavities and two types of half-space materials. It was assumed that the elastoplastic half-space obeys the Mohr-Coulomb fracture criterion.

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Stress State of Disk Tool Attachment Points on Tetrahedral Prisms between Axial Bits

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.770.434 ◽

2015 ◽

Vol 770 ◽

pp. 434-438 ◽

Cited By ~ 9

Author(s):

A.A. Khoreshok ◽

L.E. Mametyev ◽

A.Yu. Borisov ◽

A.V. Vorobyov

Keyword(s):

Stress State ◽

Strain State ◽

Stress Strain ◽

Stress Strain State ◽

Disk Tool ◽

Working Bodies ◽

Rock Faces

The paper presents results of simulation of stress-strain state of disk tools attachment points on tetrahedral prisms of working bodies of multipurpose roadheaders while cutting of coal and rock faces.

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Numerical approach for estimation of stress strain state of deep tunnels

E3S Web of Conferences ◽

10.1051/e3sconf/20199704064 ◽

2019 ◽

Vol 97 ◽

pp. 04064

Author(s):

Adilov Farkhadjan ◽

Yuldoshev Bakhtiyor ◽

Abirov Rustam ◽

Miralimov Mirzakhid

Keyword(s):

Stress State ◽

Theoretical Calculation ◽

Fractured Rocks ◽

Strain State ◽

Numerical Approach ◽

Static Case ◽

Stress Strain ◽

Deep Excavations ◽

Stress Strain State

Numerical approach and results of theoretical calculation of deep tunnels are described in this issue. Here described surrounding continuum is fractured rocks. Calculation provided in static case. Results of this investigation aimed for estimation of stress state and development of strengthening measures of deep excavations.

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Study of Changes in Time and in Space of Stressed State of Geological Environment

Геология и геофизика Юга России ◽

10.46698/vnc.2020.43.14.005 ◽

2020 ◽

Author(s):

М.Г. Попов ◽

О.Г. Попова

Keyword(s):

Stress State ◽

Power Plants ◽

Strain State ◽

Local Network ◽

Tectonic Activity ◽

Depth Interval ◽

Geological Environment ◽

Stress Strain ◽

Stress Strain State ◽

Anisotropy Index

При оценке сейсмической и экологической опасности напряженно- деформированное состояние геологической среды является важнейшей геодинамической характеристи- кой районов гидравлических (ГЭС) и атомных (АЭС) электростанций, предприятий ядерного топливного цикла (ЯТЦ), химической промышленности, стратегически важных объектов, густонаселенных мегаполи- сов и курортных районов. Цель работы. В статье обобщены полученные результаты значений геодинами- ческих показателей напряженно-деформированного состояния среды для разных по своей тектонической активности районов РФ. Методы исследования. Локальный сейсмо-экологический мониторинг (ЛСЭМ) позволяет оценивать значения геодинамических показателей анизотропности γ и напряженного состо- яния среды S по энергии обменных волн PS от далеких землетрясений. Эти показатели характеризуют состояние среды во времени и в пространстве. Наблюдения во всех регионах проводились с помощью локальной сети (площадная расстановка) трех компонентными станциями типа Дельта-Геон. Результа- ты. Приведены основные закономерности изменения значений геодинамических показателей для одного интервала глубин: диапазон значений γ и S в районах разной тектонической активности, цикличность их изменений и влияние на них внешних природных факторов (Луны, Солнца, солнечной активности и т. д.). По результатам самых длительных наблюдений ЛСЭМ (1995-2006г) на Кавминводском полигоне (сейс- моопасный Минераловодский регион) получены 3‑х мерные модели показателя анизотропности γ и про- ведена оценка показателей напряженного состояния S на разных уровнях глубин. Показано, что характер распределения показателя анизотропности γ непрерывно изменяется по глубине, латерали и во времени. Выявлена цикличность в изменении показателя S во времени на всех глубинах. Создание таких 3‑х мер- ных моделей и для других особо важных объектов позволит дать более объективную картину напряженно- деформированного состояния геологической среды, что требует, однако, более длительных наблюдений When assessing seismic and environmental hazards, the stress-strain state of the geological environment is the most important geodynamic characteristic of the areas of hydraulic (HPP) and nuclear (NPP) power plants, nuclear fuel cycle (NFC) enterprises, the chemical industry, strategically important objects, densely populated megacities and resort areas. Aim. The article summarizes the results obtained for the values of the geodynamic indicators of stress-strain state of the medium for regions of the Russian Federation that are different in their tectonic activity. Methods. Local seismic-ecological monitoring (LSEM) allows us to assess the values of the geodynamic indicators of anisotropy and the stress state of the medium S from the energy of the exchange waves PS from distant earthquakes. These indicators characterize the state of the environment in time and space. Observations in all regions were carried out using a local network (areal arrangement) of three component stations of the Delta-Geon type. Results. The basic laws of changing the values of geodynamic indicators for one depth interval are presented: the range of γ and S values in regions of different tectonic activity, the cyclical nature of their changes, and the influence of external natural factors (the Moon, the Sun, solar activity, etc.) on them. According to the results of the longest observations of the LSEM (1995-2006) at the Kavminvodsky test site (seismic hazardous Mineralovodsk region), 3‑dimensional models of the anisotropy index were obtained and stress state indicators S were evaluated at different depth levels. It is shown that the nature of the distribution of the anisotropy index continuously varies in depth, laterally, and in time. The cyclical nature of the change in S over time at all depths is revealed. The creation of such 3D models for other particularly important objects will allow us to give a more objective picture of the stress-strain state of the geological environment, which requires, however, longer observations

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Modeling the stress-strain state of a circular plate subject to general corrosion according to various models

E3S Web of Conferences ◽

10.1051/e3sconf/202126303009 ◽

2021 ◽

Vol 263 ◽

pp. 03009

Author(s):

Ilya Ovchinnikov ◽

Vladimir Avzovin

Keyword(s):

Experimental Data ◽

Stress State ◽

Circular Plate ◽

Strain State ◽

Corrosive Wear ◽

Operating Conditions ◽

General Corrosion ◽

Stress Strain ◽

Stress Strain State ◽

Kinetics Of

Quite a lot of works have been devoted to the problem of modeling the behavior of thin-walled structures exposed to an aggressive environment leading to corrosive wear of their surface. Researchers have proposed a fairly large set of models of corrosive wear, taking into account the influence of various factors on the kinetics of corrosion (time, material, temperature, the nature of the corrosive environment, the stress-strain state of the structure). Moreover, different authors often propose different models for the same conditions. In the article under consideration, a rather unique comparative study of three corrosion models proposed by different authors (Dolinsky V.M., Gutman E.M., Ovchinnikov I.G.) was carried out to simulate the behavior of the same circular plate subjected to the combined action of load and corrosion wear and tear. Moreover, the identification of the models, that is, the determination of the coefficients included in them, was carried out using the same experimental data. These models were then used to simulate the behavior of plates subject to corrosive wear under various loads. The results of numerical simulation were compared with experimental data obtained during testing of corrosive plates. Interestingly, in the models used, the effect of the stress state on the kinetics of corrosion was taken into account using different invariants of the stress state: the stress intensity in V.M. Dolinsky, medium voltage in the model of E.M. Gutman, and the specific energy in the model of I.G. Ovchinnikov. The analysis showed that the difference from the experiment when using the three models considered does not exceed 9.3%. The discrepancy between the results obtained using different models is also within the acceptable range, which suggests that all three models can be used to predict the behavior of plates under corrosive wear conditions. However, it is of interest to conduct research on the predictive capabilities of models on large forecast arms that go beyond the scope of experimental studies. At the same time, carrying out numerical experiments to simulate the behavior of complex structures in a stressed state and subject to corrosive wear, using several models that allow a good description of the experimental data and the most complete consideration of the operating conditions, makes it possible to obtain a more complete and versatile picture of what is happening in design processes, in comparison with the calculations performed according to one model, even if it describes the experimental data well.

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STRESS-STRAIN STATE IN BOUNDARY LAYER OF THE CIRCULAR PLATES WITH VARIOUS THICKNESSES BASED ON THE REFINED THEORY

Problems of Strength and Plasticity ◽

10.32326/1814-9146-2020-82-1-32-42 ◽

2020 ◽

Vol 82 (1) ◽

pp. 32-42

Author(s):

Val.V. Firsanov ◽

Q.H. Doan ◽

N.D. Tran

Keyword(s):

Boundary Layer ◽

Stress State ◽

Strain State ◽

Three Dimensional ◽

Refined Theory ◽

Circular Plates ◽

Equilibrium Equations ◽

Stress Strain ◽

Stress Strain State ◽

Three Dimensional Elasticity

A variant of the refined theory on calculation of the stress-strain state of circular plates with symmetrically various thicknesses according to an arbitrary law in the radial direction was presented. Equations of the plate state were established by using the three-dimensional elasticity theory. The required displacements were approximately calculated according to upright direction to the middle plane by polynomials with two degrees higher than in the classical Kirchhoff - Love theory. The differential equation at equilibrium in displacements with various coefficients was obtained by using means of the Lagrange variational principle. The direct integration of the equilibrium equations in the three-dimensional elasticity theory was used to determine the transverse normal and shear stresses. Of an isotropic circular plate with changing in thickness by using the analyzing Fourier chain, the obtained differential equilibrium equations in displacements with variable coefficients containing supplement components and taking into account of the effect of thickness on the stress-strain state of the plate. Examples of calculating the stress state of a circular plate with a thickness varying according to linear and parabolic laws under the action of a uniformly distributed load were considered. The limited difference method was employed to solve the boundary value problem. Comparison results of the refined and classical theories were investigated. It is demonstrated that the study on the stress state in the zones of its distortion (compounds, local loading zones, etc.) should use a refined theory, since the additional corresponding stresses of the “boundary layer” type are of the same order with the values of the main (internal) stress state. This is important to increase the reliability of strength calculations of such elements of aircraft-rocket structures as the power housings of aircraft, their various transition zones and connections, as well as objects in various engineering industries.

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Performance comparison of various types of embankment dams in relation to the conditions of the Mullalakh HPP

Vestnik MGSU ◽

10.22227/1997-0935.2021.2.202-219 ◽

2021 ◽

pp. 202-219

Author(s):

Aleksei A. Podvysotckii ◽

Mikhail P. Sainov ◽

Andrey Yu. Kirichenko

Keyword(s):

Stress State ◽

Strain State ◽

Hydraulic Engineering ◽

Engineering Practice ◽

Seismic Loads ◽

Stress Strain ◽

Embankment Dams ◽

Stress Strain State ◽

Concrete Face ◽

High Seismicity

Introduction. Several types of embankment dams are used in the hydraulic engineering practice. However, the choice of a dam is individual for each hydraulic engineering project, as it takes account of specific features and natural conditions. This paper compares two types of rockfill dams (the one having a concrete face and the other having an asphalt-concrete diaphragm) in relation to the Mullalakh HPP on the Pskem River in the Republic of Uzbekistan. The dam height is 85 m. The comparison was performed from the standpoint of the dam performance in case of exposure to static forces and high seismicity. Materials and methods. The analysis of (1) the stress-strain state (SSS), (2) the stability of slopes exposed to regular and irregular load combinations was conducted for two types of dams. All calculations were performed in the two-dimensional domain. The analysis of the stress-strain state took account of the non-linear behavior of the soil ground and the contact interaction between structural elements. Seismic loads, included into the scope of irregular loads, were identified using the response spectrum method applied to particular periods and self-oscillation modes. Slope stability was analyzed with regard for the stress state of soils identified in the course of SSS calculations. Results. Each type of embankment dams has its specific features. The asphalt diaphragm dam is worse at perceiving high seismic loads. Its SSS during an earthquake features strength loss and emergence of soil discontinuity zones. The disadvantage of a concrete face dam is the insufficient safety of its anti-seepage element. Supplementary measures are needed to ensure the appropriate stress state of the face. Another finding is that the slopes of both types of dam do not demonstrate a sufficient stability factor, if the slope ratio equals to 1.5 during a 9-point earthquake. Conclusions. In high seismicity regions, a concrete faced dam demonstrates better performance than the asphalt diaphragm dam if both are exposed to static and seismic forces.

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