scholarly journals Calculation of the stressed state of a soil massif in the filtration of a liquid from a point source

2018 ◽  
Vol 196 ◽  
pp. 01022
Author(s):  
Vladimir Andreev ◽  
Anatoliy Avershyev
Keyword(s):  
Stress State ◽  
Stressed State ◽  
Point Source ◽  
Fracture Site ◽  
Spherical Coordinates ◽  
Sewer Pipes

The rupture of water and sewer pipes leads to numerous accidents (subsidence, swelling, etc.). This is especially characteristic for clay, loess, peat and other soils. We consider the stress state of clay array at different models on fluid propagation from a fracture site. Accordingly, the problems are solved in cylindrical and spherical coordinates. The problem is solved by the methods of stationary and non-stationary moisture elasticity. The feature of the calculation is the accounting of the inhomogeneity of the clay during moistening.

scholarly journals NONLINEAR DEFORMATION-FORCE MODEL OF A CONCRETE BAR WITH NON-METALLIC COMPOSITE REINFORCEMENT IN THE GENERAL CASE OF A STRESSED STATE

2021 ◽  
Vol 3 (1) ◽  
pp. 6-26
Author(s):  
I. Karpiuk ◽  
◽  
Ye. Klymenko ◽  
V. Karpiuk ◽  
M. Karpiuk ◽  
...  
Keyword(s):  
Stress State ◽  
Stressed State ◽  
Bearing Capacity ◽  
Nonlinear Deformation ◽  
Complex Stress ◽  
Complex Stress State ◽  
Force Model ◽  
Metallic Composite ◽  
Aggressive Environment ◽  
Deformation Force

The article discusses a nonlinear deformation-force model of a concrete bar structure with a non-metallic composite reinforcement (NKA-FRP) in the general case of a stressed state, when all four internal force factors from an external load (namely, bending and twisting moments, transverse and longitudinal forces). A sufficiently deep and meaningful analysis of well-known studies on the selected topic is given. It has been established that the proposed nonlinear deformation-force model of a bar structure with FRP in the general case of a stressed state can be practically useful due to the possibility of its application in the design or reinforcement of beams, girders, columns and elements of rosette trusses of rectangular cross-section, which are operated under aggressive environmental conditions. This model can also be used to check the bearing capacity of existing FRP concrete bar structures, which operate not only under the influence of an aggressive environment, but also under conditions of a complex stress-strain state. In the course of the research, an algorithm was developed for determining the bearing capacity of the design section of a concrete rod with FRP under its complex stress state. General physical relations for the design section are given in the form of a stiffness matrix. The algorithm for calculating a concrete bar with FRP consists of a block for inputting the initial data, the main part, auxiliary subroutines for checking the conditions for increasing the load vector and depletion of the bearing capacity, as well as a block for printing the calculation results. At each stage of a simple static stepwise increasing load, the calculation is carried out by performing a certain number of iterations until the accuracy of determining all components of the deformation vector satisfies a certain predetermined value. The features and patterns of changes in normal and tangential stresses, generalized linear and angular deformations, as well as the equations of equilibrium of a concrete bar with FRP, which operates under the influence of an aggressive environment under conditions of a complex stress state, are also considered.

scholarly journals Influence of paleodislocation intensity and modern movements on the stressed state of massif

2020 ◽  
Vol 168 ◽  
pp. 00060
Author(s):  
Dmytro Pymonenko
Keyword(s):  
Stress State ◽  
Stress Field ◽  
Stressed State ◽  
Central Region ◽  
Experimental Studies ◽  
Physicomechanical Properties ◽  
Stress Fields ◽  
Tectonic Processes ◽  
Statistical Relationships ◽  
Main Components

To study the nature of the forces determining the stress state of the massif, the results of experimental studies of determining numerical values and spatial orientation of the main components of the active stress field using the local hydraulic fracturing method in coal mines of Central Region of Donbas are compared with maps characterizing the intensity of the distribution of paleo-and modern tectonic processes in the area of Donbas. Statistical relationships between indicators characterizing the stress state and the physicomechanical properties of rock are established. The results of performed studies show that the stress fields measured under the conditions of the mines of the Central Region of Donbas are mainly due to modern movements, but the paleological disturbances of tectonic blocks with disjunctive dislocations have a significant effect on the change in the stress state of the massif.

scholarly journals Creep of isotropic homogeneous and nonaging of linear-viscoelastic materials under the complex stress state

2019 ◽  
pp. 150-153
Author(s):  
Y. V. Pavlyuk
Keyword(s):  
Stress State ◽  
Stressed State ◽  
Complex Stress ◽  
Complex Stress State ◽  
Complex Stressed State ◽  
Viscoelastic Materials ◽  
Linear Viscoelastic ◽  
Thin Walled ◽  
Hereditary Properties ◽  
Axial Stretching

The relaxation of isotropic homogeneous and non-aging linear-viscoelastic materials under conditions of complex stress state is considered. Thin-walled tubular specimens of High Density Polyethylene (HDPE) for creep under a single-axial stretching, with a pure twist and combined load tension and torsion are considered as base experiments, tests. The solution is obtained by generalizing the initial one-dimensional viscoelasticity model to a complex stressed state, constructed using the hypothesis of the proportionality of deviators. The heredity kernels are given by the Rabotnov’s fractional-exponential function. The dependence between the kernels of intensity and volumetric creep is established, which determine the scalar properties of linear viscoelastic materials in the conditions of a complex stressed state in the defining equations of the type of equations of small elastic-plastic deformations, and the kernels of longitudinal and transverse creep defining the hereditary properties of linear-viscoelastic materials under the conditions of the uniaxial tension. The problems of stress relaxation calculation of thin walled tubes under combined tension with torsion have been solved and experimentally approved.

scholarly journals ANALYSIS OF ACOUSTIC DIAGNOSTICS ERRORS OF STRESS STATE FOR SHAPED PROFILES OF METAL STRUCTURES

2016 ◽  
Vol 5 ◽  
pp. 50-57
Author(s):  
Gregorii Tymchik ◽  
Marina Filippova ◽  
Mariia Demchenko
Keyword(s):  
Stress State ◽  
Stressed State ◽  
Total Error ◽  
Human Intervention ◽  
Shadow Method ◽  
Scanning Method ◽  
Metal Structures ◽  
Acoustic Diagnostics ◽  
The Impact

The article is devoted to analysis of the errors that occur when acoustic diagnostics of stress state for shaped profiles of metal structures. The analysis of methods for acoustic diagnostics of stressed state of shaped profiles was conducted using mirror-shadow method and areas, causing the occurrence of errors, were revealed. The analysis of tool, methodical and subjective errors that accompany acoustic diagnostics of stress state of shaped profile allowed offering recommendations for their reduction and increasing the reliability of diagnostics results. The necessity of reducing the total error for determining the stress state caused by factors accompanying acoustic diagnostics of shaped profiles was shown. Application of automation during the acoustic diagnostics of stress state for shaped profiles of metal structures was proposed. This will significantly increase the reliability of the data by reducing human intervention in the process of measurement and processing results. Technical and methodological solutions were proposed that will reduce the impact of the total error on the result of acoustic diagnostics of stress state for shaped profiles using the mirror-shadow scanning method.

scholarly journals The applicability of LID facilities as an adaptation strategy of urban CSOs management for climate change

2021 ◽  
Author(s):  
Kyungmin Kim ◽  
Ryoungeun Kim ◽  
Jeonghyeon Choi ◽  
Sangdan Kim
Keyword(s):  
Climate Change ◽  
Water Quality ◽  
Point Source ◽  
Low Impact Development ◽  
Extreme Rainfall ◽  
Adaptation Strategy ◽  
Urban Watersheds ◽  
Combined Sewer Overflows ◽  
Sewer Pipes ◽  
Combined Sewer

Abstract The magnitude and frequency of extreme rainfall due to climate change is increasing. Increasing rainfall causes serious hydrological problems in cities. Rainfall does not infiltrate the soil, but mostly flows through the sewer pipes into the stream. Most old urban watersheds have combined sewer pipes. When rainfall exceeds the capacity of the combined sewer pipes, sewage mixed with stormwater overflows the sewer pipes and flows directly into the stream. This is called Combined Sewer Overflows (CSOs). CSOs enter the stream with non-point source pollutants accumulated on the surface and pollute the stream. CSOs are one of the major water quality problems in older urban watersheds. This can be solved by replacing the combined sewer pipes with separated sewer pipes, but in reality it requires astronomical costs. As an alternative, the Low Impact Development (LID) technique has recently been introduced. In this study, we analyzed the effects of climate change on CSOs in urban watersheds and applied LID techniques to offset the effects. The LID facility was applied with the most commonly used Bio-Retention cells.

scholarly journals Periprosthetic femoral fractures in sideways fall configuration: comparative numerical analysis of the influence of femoral stem design

2020 ◽  
Vol 30 (2_suppl) ◽  
pp. 86-93
Author(s):  
Massimo Franceschini ◽  
Luigi La Barbera ◽  
Alberto Anticonome ◽  
Claudia Ottardi ◽  
Atsuki Tanaka ◽  
...  
Keyword(s):  
Stress State ◽  
Clinical Data ◽  
Numerical Models ◽  
Femoral Stem ◽  
Femoral Fractures ◽  
Progressive Increase ◽  
Fracture Site ◽  
Stem Design ◽  
Vertical Loading ◽  
Sideways Fall

Introduction: The aim of this study was to investigate the mechanisms of periprosthetic fractures occurring as a result of a sideways fall in total hip arthroplasty patients, and to compare the predictions of numerical models in terms of load distribution on the implanted femur with clinical data. Materials and methods: 3 numerical models were built: 1 for intact femur and 2 for implanted femur with a straight stem (resembling PBF, Permedica) and with an anatomical stem (resembling ABG II, Stryker). 4 loading configurations were simulated; 1 simulates a vertical load, and 3 simulate a fall with impact on the greater trochanter in different directions. Stress state calculated in the implanted femur was compared for the 2 models with reference to the intact case. These were compared with clinical data collected at a single centre (Istituto Ortopedico Gaetano Pini, Milan, Italy) where 41 patients were investigated after periprosthetic fracture: 26 patients had a straight uncemented stem and 15 an anatomical uncemented stem. Results: The maximum calculated strain in compression in the case of ABG II implanted femur was 2 times higher than in the presence of PBF stem in the vertical loading configuration. For configurations of sideways fall, in both models, there was a progressive increase of stress state in the bone with increasing angle. Simulations of sideways fall elicited results in accordance with clinical observations: due to the peculiar stem design and consequent state of stress in the bone, anatomical stems seem to induce trochanteric fractures more frequently, while for straight stems type B fractures are more likely to occur. Conclusions: Clinical findings confirmed numerical model predictions: stem design seems to highly influence distribution of stress in the bone and consequent localisation of the fracture site.

scholarly journals Method of finite bodies for determination of the plane stressed state of rectangular plates with a rectangular hole

2019 ◽  
pp. 170-173
Author(s):  
V. P. Revenko
Keyword(s):  
Stress State ◽  
Quadratic Form ◽  
Boundary Conditions ◽  
Stressed State ◽  
Rectangular Plates ◽  
Rectangular Hole ◽  
Connected Surface ◽  
Ideal Contact ◽  
Finite Sum

The paper is devoted to the determination of the stress-deformed state of structurally heterogeneous bearing rectangular plates with a rectangular hole. The new analytical-numerical method (finite bodies) was used, to find the stress state of the plate with a hole. The method of finite bodies uses the conditional partition of the doubly-connected surface of the plate into simpler connected rectangular parts. On the lines of conditional contact, the conditions of ideal contact are taken into account, which ensure the equality of stresses, deformations and displacements. The perturbed stressed state, which is presented in the form of a series of functions, which is rapidly intercepted at a distance from the outline of the hole, is considered. A finite sum of solutions of a plane problem is used and the stress state of a perturbed state is given as a sum of a series for nonorthogonal functions. The components of vector of displacements and stresses are written. The determination of the coefficients of the sum of a series is based on the proposed method of satisfying all boundary conditions and the conditions of ideal contact to find the minimum of a generalized quadratic form. The numerical criterion for the convergence of the method is theoretically established. It is shown that the accuracy of satisfaction of boundary conditions and conditions of ideal contact is estimated by one number – the minimum of a generalized quadratic form.

scholarly journals APPLICABILITY ANALYSIS OF STRESS STATE CRITERIA FOR DESCRIPTION OF BABBIT LAYER FATIGUE DESTRUCTION IN SLIDER BEARINGS

2019 ◽  
Vol 2019 (9) ◽  
pp. 4-14
Author(s):  
Михаил Зернин ◽  
Mikhail Zernin
Keyword(s):  
Experimental Investigation ◽  
Stress State ◽  
Stressed State ◽  
Process Simulation ◽  
Fatigue Process ◽  
Slider Bearings

The criteria of stressed state equivalence used for fatigue process simulation are shown. Different criteria offered by various investigators for slider bearings are described. A procedure is offered for the estimate of different criteria applicability on the basis of experimental investigation results. It is shown that for tin-based babbit layers it is possible to use the first basic stress as a criterion, but at that it is necessary to take into account a propping action of lubricant coming in a crack under pressure (radial stresses).

XRMF applications of a monolithic, polycapillary, focusing x-ray optic

1996 ◽  
Vol 54 ◽  
pp. 240-241
Author(s):  
D. A. Carpenter ◽  
Ning Gao ◽  
G. J. Havrilla
Keyword(s):  
Trace Elements ◽  
Point Source ◽  
Focal Spot ◽  
Fluorescence Analysis ◽  
X Rays ◽  
Focal Distance ◽  
Spot Diameter ◽  
X Ray ◽  
Focal Spot Diameter

A monolithic, polycapillary, x-ray optic was adapted to a laboratory-based x-ray microprobe to evaluate the potential of the optic for x-ray micro fluorescence analysis. The polycapillary was capable of collecting x-rays over a 6 degree angle from a point source and focusing them to a spot approximately 40 µm diameter. The high intensities expected from this capillary should be useful for determining and mapping minor to trace elements in materials. Fig. 1 shows a sketch of the capillary with important dimensions.The microprobe had previously been used with straight and with tapered monocapillaries. Alignment of the monocapillaries with the focal spot was accomplished by electromagnetically scanning the focal spot over the beveled anode. With the polycapillary it was also necessary to manually adjust the distance between the focal spot and the polycapillary.The focal distance and focal spot diameter of the polycapillary were determined from a series of edge scans.

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