Analysis of the volumetric stress state around a mine working of finite length

The aim of the work. The effect of the curvature of the rounding of torus surfaces during the formation of a cylindrical product (glass) is investigated, taking into account the plastic thinning of the deformable material at the end edges of the matrix and pressing punch. Methods. The existing scheme for determining the power parameters of sheet drawing is analyzed, based on the assumption of the implementation of some abstract stress state in the material; mainly conditional tensile strength. At the same time, the possibility of forming the product without destruction determines the obvious overestimation of the stress level. A mathematical model of the volumetric stress state of the metal is being developed, which makes it possible to assess the deformation and stress state during the formation of a cold-drawn product, i. e. the folding of the sheet blank along the end radius of the rounding of the pressing punch and the steady-state process of drawing the blank into the deformation zone with successive bending/straightening of the material along the edge of the matrix are considered. The level of radial stresses during folding and stretching of sheet material is estimated, taking into account its strain hardening and thinning, which determine the forming force. The obtained results will make it possible to simulate the stress-strain state of the metal during the development of sheet drawing technology: to establish the amount of thinning, to estimate the level of radial stresses in the formation of rounding of torus surfaces along the end edges of the matrix and the pressing punch, as well as to determine the power parameters of the formation, which will prevent the destruction of the pulled part, guaranteeing obtaining high-quality products and more accurately choosing the deforming equipment.

The stress state of rocks at the actual boundary of a mine working

Soil Mechanics and Foundation Engineering ◽

10.1007/bf01704953 ◽

1973 ◽

Vol 10 (4) ◽

pp. 284-289

Author(s):

V. I. Sheinin

Keyword(s):

Stress State ◽

Mine Working

Stress state of saturated porous mass near a horizontal mine working

Soviet Applied Mechanics ◽

10.1007/bf00884354 ◽

1979 ◽

Vol 15 (3) ◽

pp. 185-191

Author(s):

L. P. Khoroshun ◽

R. M. Israfilov

Keyword(s):

Stress State ◽

Mine Working ◽

Porous Mass ◽

Horizontal Mine Working

Generalized calculating diagram of steel, operating under conditions of volumetric stress state

Architecture Construction Education ◽

10.18503/2309-7434-2017-2(10)-12-18 ◽

2017 ◽

pp. 12-18

Author(s):

A.L. KRISHAN ◽

◽

E.A. TROSHKINA ◽

E.P. CHERNYSHOVA ◽

M.A. ASTAFEVA ◽

...

Keyword(s):

Stress State ◽

Volumetric Stress

Теоретичні та експериментальні методи визначення характеристик міцності лопаток турбін при термомеханічному навантаженні

Aerospace technic and technology ◽

10.32620/aktt.2021.4sup1.13 ◽

2021 ◽

pp. 93-101

Author(s):

Євген Олександрович Неманежин ◽

Валерій Миколайович Івко ◽

Юрій Іванович Торба

Keyword(s):

Stress State ◽

Turbine Blades ◽

Complex Loading ◽

Effect Of Temperature ◽

Internal Cooling ◽

Centrifugal Forces ◽

Thermomechanical Loading ◽

Engine Operation ◽

Thermomechanical Testing ◽

Volumetric Stress

The subject of this article is the methods of research and evaluation of the properties of turbine blades of a cooled structure under thermomechanical loading. The purpose of the article is to review the world achievements of leading enterprises and research institutions in the issue of fatigue tests of turbine blades under complex loading (cyclic temperature exposure, dynamic and static loading), as well as an overview of the state of this topic at SE "Ivchenko-Progress" and suggestions for its further studying. As a result of the analysis of publications and scientific articles, it can be concluded that specialized research institutes and leading aircraft engine-building enterprises from the end of the twentieth century are studying the properties of turbine blades in the conditions of their operation as part of an engine. In world practice, there are calculated and experimental methods for thermomechanical testing of turbine blades. These tests are aimed at determining the most damaging loads, establishing the flight cycle modes at which these loads are recorded. As a result, it was found that the greatest threat to the strength of the turbine blades is carried by transient modes of engine operation, which are short in time (measured in seconds), but at which there is a change in the parameters of the temperature field, loads from axial and centrifugal forces. And it is the cycling of these parameters that leads to a decrease in the cyclic durability of the turbine blades, especially of the cooled structure (the presence of perforations, internal cooling channels, and other structural elements leads to a complication of the volumetric stress state of the blades). The article analyzes various crystallographic structures of blades and their relationship with the volumetric stress state; examples of studies that were carried out at SE "Ivchenko-Progress" and their results are given, which emphasize the need for further experiments in the field of assessing strength characteristics under complex cyclic loading. An example of an installation for testing blade joints and samples of gears is considered, which can be adapted for testing blades with three-component loading (temperature, dynamic loads, and imitation of the effect of centrifugal forces). It is concluded that when using exclusively computational methods, it is impossible to reliably estimate the level of stresses and their distribution since the calculations are limited by the boundary conditions, which are set according to the capabilities of a particular computational model. Summing up, it can be noted that it is advisable to start assessing the strength of blades under thermomechanical loading with several series of tests of samples of blade material to study the effect of temperature and power cycles of loads, the effect of the orientation of the load vector concerning the crystallographic orientation of the blade. It is noted that tests of full-scale blades under thermomechanical loading are also important since the features of the volumetric stress state of the material during real operation of the blades as part of an engine are not reproduced during testing of samples. The above entails the development of methods and specialized installations for thermomechanical testing.

A Study of the Stress State of Underground Gas Pipelines in Mine Working Zones Using the Method of Internal Response Function

Strength of Materials ◽

10.1007/s11223-019-00071-y ◽

2019 ◽

Vol 51 (2) ◽

pp. 252-262

Author(s):

I. V. Orynyak ◽

Z. S. Yaskovets

Keyword(s):

Stress State ◽

Response Function ◽

Mine Working ◽

Gas Pipelines ◽

Internal Response

CALCULATION AND DESIGN OF CELLULAR CARRYING LAYERS OF AIRFIELD RUNWAY PAVEMENTS

Herald of Dagestan State Technical University Technical Sciences ◽

10.21822/2073-6185-2019-46-4-176-185 ◽

2020 ◽

Vol 46 (4) ◽

pp. 177-185

Author(s):

G. M. Murtazaliev ◽

M. M. Batdalov ◽

A. I. Akayev ◽

A. I. Bulgakov ◽

M. M. Payzulaev

Keyword(s):

Reinforced Concrete ◽

Stress State ◽

Honeycomb Structure ◽

Complex Stress ◽

Complex Stress State ◽

Integral Parameter ◽

Steel Reinforced Concrete ◽

Steel Sheets ◽

Volumetric Stress ◽

The Impact

Objectives. The need to ensure the reliable functioning of expensive airfield structures poses great challenges for surveyors, designers, builders and operators of these structures. These tasks are complicated by the continuous development of aircraft, an increase in the intensity of their movement, an increase in mass, take-off and landing characteristics of aircraft and the degree of operational impact of aircraft on airfield structures. The aim of the study is the technological solution model proposed by the authors for the carrier layer of artificial runway pavement in the form of a honeycomb structure of closed steel sheets filled with concrete along with a method for assessing the strength and determining the rigidity of its aggregate.Method. A method is proposed for assessing the ultimate strength and determining the real stiffness parameters of structural layers of a runway with a constructive solution to the question of concrete work in cramped conditions (“cage effect”) from the impact of manifold repeated operational aircraft loads. This method is based on the fundamental principles of the deformation theory of reinforced concrete, developed by V.M. Bondarenko and elaborated in relation to the volumetric stress state of reinforced concrete structures in the works by G.A. Geniev, K.L. Surov and V.I. Rimshin.Result. An analytical dependency is obtained for establishing a discrete value, a generalised (integral) parameter of the material deformation of the carrier layer, i.e. the equation of the mechanical state of steel-reinforced concrete in a complex stress state, as well as the repeated application of an operational aircraft load at an arbitrary stress point of the artificial runway pavement taking into account the influence of changes in strength, reinforcement, temperature, humidity and rheological factors.Conclusion. The introduction of new technological principles for reinforcing and concrete laying into the design solutions of the bearing layers of artificial runway pavement allows their bearing capacity and rigidity to be significantly increased due to the redistribution of impact energy and the efficient use of the properties of structural materials during loading.

Application of roof bolting to reduce water inflow into mine workings during the crossing of tectonic faults

E3S Web of Conferences ◽

10.1051/e3sconf/202128001006 ◽

2021 ◽

Vol 280 ◽

pp. 01006

Author(s):

Oleksandr Krukovskyi ◽

Viktoriia Krukovska ◽

Yurii Vynohradov ◽

Vladimir Dyomin

Keyword(s):

Stress State ◽

Mine Working ◽

Numerical Study ◽

Water Pressure ◽

Stable State ◽

Calculated Data ◽

Water Inflow ◽

Roof Bolting ◽

Tectonic Disturbance ◽

Hydrogeological Conditions

In this work, the problem of water inflow reduction in Ukrainian coal mines, which are distinguished by difficult hydrogeological conditions, was considered. A numerical study of the change in water inflow into a mine working when it crosses a tectonic fault was carried out. The cases when the permanent working was supported by frame supports and roof bolts were considered. The calculation of stress fields, zones with inelastic deformations and coefficients of permeability, which depend on the stress state and takes into account tectonic and natural permeability of the rocks, was performed. The results of calculating the water pressure and water inflow into the mine working in all considered cases are presented in the article. Analysis of the calculated data showed that a disturbed area, which covered water-bearing ricks, was formed in the roof of the mine working with the frame support. Within this area, water can move towards the contour of the mine working. The filtration permeability of the host rocks increases significantly when the mine face approaches the tectonic disturbance. The flow rate of water reaches critical values. The use of roof bolting restrains the unloading of the boundary rocks from the rock pressure and keeps them in a triaxially compressed stress state. The permeability value decreases by the value of its technological component. In different areas of the intersection of tectonic disturbance, the water inflow into the mine working with roof bolting is 3-8 times less than in the working, supported by frame supports. Therefore, the use of roof bolting allows not only to keep the mine working in a stable state, but also to significantly reduce water inflows at complicated hydrogeological conditions.

Stress state of a beam with supporting elements of finite length under bending

Materials Science ◽

10.1007/bf00558562 ◽

1996 ◽

Vol 31 (3) ◽

pp. 385-385 ◽

Cited By ~ 1

Author(s):

Kaddur Ziyad

Keyword(s):

Stress State ◽

Finite Length