scholarly journals SAFETY ASSESSMENT OF DAMS MADE OF GROUND MATERIALS

2020 ◽  
Vol 2 (4) ◽  
pp. 45-49
Author(s):  
V. Orehov ◽  
G. Alekseev
Keyword(s):  
Safety Assessment ◽  
Strain State ◽  
Triaxial Compression ◽  
Strength Properties ◽  
Numerical Calculations ◽  
Stress Strain ◽  
Limit Values ◽  
Properties Of Materials ◽  
The Stability ◽  
Spatial Stress

the stability of the dam on Rogunskaya HPP made of ground materials is studied on the basis of numerical calculations of its spatial stress-strain state. The deformation and strength properties of the materials composing the dam body defined in the triaxial compression devices were used in the calculations. Limit values of strength properties of materials and controlled values of diagnostic indicators of a dam at which safety of its work is provided are established.

Analysis of the stress-strain state of copper M0B under different schemes of equal channel angular pressing and its effect on the structure and physical and mechanical properties

2019 ◽  
pp. 47-53
Author(s):  
L. F. Sennikova ◽  
G. K. Volkova ◽  
V. M. Tkachenko
Keyword(s):  
Equal Channel Angular Pressing ◽  
Strain State ◽  
Physical And Mechanical Properties ◽  
Strength Properties ◽  
Stress Strain ◽  
Loading Pattern ◽  
Stress Strain State ◽  
Angular Pressing ◽  
Fine Copper ◽  
Copper Structure

The results of studies of the stress-strain state of copper M0b after deformation under different schemes of equal channel angular pressing (ECAP) are presented. The level of macro and micro stresses in copper has been determined in various ECAP modes. It is shown that the strength properties, deformation porosity and parameters of the fine copper structure differ depending on the loading pattern.

scholarly journals Settlement and bearing capacity of water-saturated soils of foundations of finite width under static impact

Vestnik MGSU ◽  
2021 ◽  
pp. 463-472
Author(s):  
Zaven G. Ter-Martirosyan ◽  
Armen Z. Ter-Martirosyan ◽  
Ahmad Othman
Keyword(s):  
Bearing Capacity ◽  
Strain State ◽  
Water Saturation ◽  
Strength Properties ◽  
Finite Width ◽  
Stress Strain ◽  
Linear Deformation ◽  
Stress Strain State ◽  
Linear And Nonlinear ◽  
Water Saturated

Introduction. In case of brief exposure to static loads or dynamic loads, in conditions of absence of drainage, distribution of total stresses between the skeleton of soil and pore gas-containing water should be taken in account. The situation of the stress-strain state of the base is further complicated when we consider the degree of water-saturation of soil of the foundation (0.8 < Sr ≤ 1). The aim of the study is to pose and solve problem of the stress-strain state of a water-saturated soil massif, Including settlement and bearing capacity of a water-saturated base of a foundation of finite width, depending on the degree of water saturation of soils, taking into account the linear and nonlinear properties of the skeleton of soil and the compressibility of pore gas-containing water. Materials and methods. Henckyʼs system of physical equations are used as a calculation model to describe the relationship between deformation and stresses of soil, which takes into account the influence of the average stress on the deformation and strength properties of the soil. This system allows us to represent the linear deformation of the soil as the sum of the volumetric and shear components of the soil of this deformation. In addition allows us too to determine the deformation of the layer of soil, as part of the compressible thickness of the base of foundation with finite width under conditions of free deformations. Results. Depending on the linear and nonlinear deformation parameters, the settlement can be developed with a damped curve (S – p) and stabilize, and can be developed with a non-damped curve (S – p) and moved to the stage of progressive settlement. Conclusions. Solutions have been made for cases when the water-saturation of the base soils changes in the range of 0.8 to 1.0. It is shown that the settlement and bearing capacity of a water-saturated base significantly depends on the degree of water saturation of soils.

scholarly journals Predicting the Stress-Strain State of the Fractured Rock Massif on the Example of Interchamber Pillars

2019 ◽  
Vol 9 (2) ◽  
pp. 4228-4233
Keyword(s):  
Strain State ◽  
Numerical Models ◽  
Fractured Rock ◽  
Strength Properties ◽  
Rock Massif ◽  
Qualitative Description ◽  
Stress Strain ◽  
Stress Strain State ◽  
Geological Surveys ◽  
Spatial Geometry

The article describes the finding of the qualitative differences in the formation of the stress-strain state of a disturbed rock massif on the example of interchamber pillars with various methods of accounting for the structural disturbance and different spatial geometry of the cracks. Three numerical models are created with different methods of accounting for the disturbances in the massif continuity: in the first model, the strength of the massif is described by the Hoek and Brown criterion; the second and the third models are rock massifs for which violations in the continuity are formed explicitly, using ready-made templates of the systems of cracks presented in the Phase2 software product. The results obtained for the different models illustrate the inaccuracies occurring in assessing the disturbance of rock massif using score criteria. Models with underrated strength properties of the rock inaccurately describe the real mechanisms of the fractured massif: the qualitative description is not consistent with the results of field observations and geological surveys of rocks in general.

scholarly journals Study of the Stress-Strain State of the Process of Drawing Wire from an Alloy of Palladium with Nickel

2020 ◽  
Vol 992 ◽  
pp. 504-510
Author(s):  
S. Sidelnikov ◽  
V. Lopatin ◽  
M. Dobrovenko ◽  
E. Lopatina ◽  
R. Sokolov
Keyword(s):  
Strain State ◽  
Current Mode ◽  
Wire Drawing ◽  
Stress Strain ◽  
Limit Values ◽  
Stress Strain State ◽  
Limit Value ◽  
Drawing Die ◽  
Metal Deformation ◽  
3D Software

This article present the results of studies of the process of wire drawing from the PdNi-5 alloy, performed using computer simulation in the DEFORM 3D software package. В качестве материала для исследований использовали сплав с содержанием 95% палладия и 5% никеля. An alloy with a content of 95% palladium and 5% nickel was a material for research. The patterns of changes in the stress-strain state for the current processing mode determined, and a more rational drawing mode with a redistribution of drawing coefficients along transitions proposed. For the proposed regime, using the created model, the values of drawing stresses, drawing forces and Cockcroft-Latham criterion determined. It was found that the stress distribution in the deformation zone corresponds to the generally accepted laws of their change, and their maximum values are realized in the metal located in the calibrating zone of the drawing die. In addition was revealed that the stresses in the current mode have limit values at the second and fourth passes. The redistribution of deformation indicators in the proposed mode allowed reduce the magnitude of these stresses and, thereby, reduce the likelihood of wire breaks. The maximum value of the Cockcroft-Latham criterion is achieved in the last transitions, but at the same time, destruction will not occur, since they do not exceed the limit value. The drawing force also decreases with the implementation of the proposed mode and does not exceed the permissible values regulated by the technical characteristics of the equipment. Since it is the proposed mode of wire drawing, it is characterized by a decrease in energy power indicators and the likelihood of wire breakage in the process of metal deformation it can be recommend it for implementation in existing production.

scholarly journals Comparison of the stress and strain intensity factors for the corner area of the structure boundary

2018 ◽  
Vol 193 ◽  
pp. 03029
Author(s):  
Lyudmila Frishter
Keyword(s):  
Strain State ◽  
Engineering Practice ◽  
Stress And Strain ◽  
Strain Intensity ◽  
Intensity Factors ◽  
Stress Strain ◽  
Elasticity Theory Problem ◽  
Limit Values ◽  
Stress Strain State ◽  
Irregular Point

The stress-strain state of structures in areas with corner cut-outs and cuts of boundaries features the occurrence of areas of stress concentration and requires assessment of strength and reliability of facilities, which is a relevant task in engineering practice. Theoretical analysis of stress-strain state (SSS) of corner cut-outs zones of the area boundary is reduced to the study of singular solutions of the elasticity theory problem with exponential features. At that, the concept of stress or strain concentration in an irregular point of the area boundary is meaningless. This paper considers the stress-strain state in the vicinity of the top of the corner cut-out of the flat area boundary, which is recorded using the intensity factors as limit values of stresses and strains. We give two approaches for obtaining the limit values for stress and strain in the vicinity of an irregular point of the plane area boundary using the stress intensity factors and the strain intensity factors. The stress-strain state in the corner cut-outs zone of structures and buildings boundary recorded in the form of limit values of stresses and strains may further be used to determine and record the influence of changing the factors of intensity of stresses and strains on SSS of structures, which is a separate task of solid mechanics. The difference in the expressions of stresses and displacements obtained for limit values of stresses and strains determines practical significance of the work when carrying out experiments and at determination of critical values of stresses and strains.

scholarly journals Stress-strain Relationship in Homogeneous and Two-layered Triaxial Test Specimens

2020 ◽  
Author(s):  
Gabriel Oliveira ◽  
Isabel Falorca
Keyword(s):  
Soil Mechanics ◽  
Triaxial Compression ◽  
Nonlinear Behavior ◽  
Confining Pressure ◽  
Test Method ◽  
Compression Tests ◽  
Stress Strain ◽  
Triaxial Apparatus ◽  
Strain Relationship ◽  
The Stability

The stress-strain relationship of a homogeneous specimen, obtained from triaxial compression test, allows to determine stiffness parameters for numerical-method based analyses in common geotechnical software. Stiffness parameters are defined as the ratio of stress to strain along an axis. However, when a heterogeneous specimen is tested, the equivalent elastic modulus that represents a simplification of the nonlinear behavior is complex. This paper presents a study intended to contribute to the debate about the degree to which conventional soil mechanics approaches can be applied to layered specimens. Triaxial compression tests were carried out on both homogeneous and two-layered specimens under a low effective confining pressure of 30 kPa. The triaxial apparatus was chosen since the applied stress and specimen boundary conditions are well defined, and the repeatability of the test method is good. The behavior of both specimens was studied in terms of the stress-strain relationship and stiffness. The main differences were crucial to understanding the composite soil-aggregate interaction, which is discussed and compared. The results indicate that the interface between composite soil and aggregate is important to keep the stability of the layer of aggregate over the soft composite soil, and practical methods of achieving that are suggested.

scholarly journals Stability of eccentrically compressed reinforced concrete elements under special impacts with account taken of shear deformations

Vestnik MGSU ◽  
2021 ◽  
pp. 49-58
Author(s):  
Sergey Yu. Savin
Keyword(s):  
Reinforced Concrete ◽  
Strain State ◽  
High Stress ◽  
Dynamic Resistance ◽  
Shear Deformations ◽  
Stress Strain ◽  
True Nature ◽  
The Stability ◽  
Concrete Elements ◽  
Strain Model

Introduction. When structural models of reinforced concrete frameworks of buildings and structures are designed, bars and plates simulate structural elements. As rule, such an approach entails rigid cohesion between reinforcement bars and concrete; thus, it fails to simulate the true nature of their joint action in the areas having high stress gradients, for example, beam-column junctions. In this regard, it’s necessary to plot analytical dependencies and develop a methodology for the stability analysis of the strain state of bar elements of reinforced concrete frameworks of buildings and structures with account taken of shear deformations at the interface between a reinforcement bar and concrete. Materials and methods. The Rzhanitsyn composite bar theory was applied to design a stress-strain model of an eccentrically compressed reinforced concrete bar. The Kelvin-Voigt model is proposed as a rheological stress-strain model of static and dynamic resistance of concrete. Results. Analytical dependencies needed to analyze the stress-strain state and stability of an eccentrically compressed reinforced concrete bar exposed to dynamic loading, were plotted. These dependencies take account of shear deformations at the interface between reinforcement bars and concrete. A nonlinear calculation algorithm was developed; it took account of the elastoplastic behavior of concrete and steel bars, when the stability problem of an eccentrically compressed dynamically loaded reinforced concrete bar was solved. Conclusions. Analytical dependencies, obtained by the author, allow to take account of shear deformations at the interface between reinforcement bars and concrete in eccentrically compressed reinforced concrete elements of frameworks of buildings and structures for the purpose of analyzing the stability of such elements exposed to special impacts caused by the unexpected failure of one bearing element of a structural system.

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