Research of throwing areols of underground pipeline in permafrost

Author(s):  
T. S. Sultanmagomedov ◽  
◽  
R. N. Bakhtizin ◽  
S. M. Sultanmagomedov ◽  
T. M. Halikov ◽  
...  

Study is due to the possibility of loss of stability of the pipeline in the process of pumping a product with a positive operating temperature and the formation of thawing halos. The article presents the ways of solving the thermomechanical problem of pipeline displacement due to thawing. The rate of formation of a thawing halo is investigated depending on the initial temperatures of the soil and the pumped product. The developed monitoring system makes it possible to study the rate of occurrence of thawing halos in the process of pumping the product. An experimental study on the formation of thawing halos around the pipeline was carried out on an experimental model. A thermophysical comparative calculation of temperatures around the pipeline on a model by the finite element method has been carried out. Keywords: underground pipeline; permafrost; thawing halo; monitoring; operating conditions; stress–strain state.

Author(s):  
V.V. LEONTYEV ◽  
E.V. KONDRATOVA ◽  
V.P. KOLOMIYCHENKO

Traditional methods for calculating welded joints are based on approximate methods for determining the forces that occur in the joint. This leads to inaccuracies in the definition of stress. In addition, this approach does not allow obtaining a complete picture of the stress-strain state of the joint. All this leads to the need to increase the coefficient of safety margin and, as a result, to increase the cost of construction. The proposed method of calculating the connection using the finite element method allows us to determine the stresses in all the elements of the connection very accurately. This makes it possible to obtain a reliable picture of the stress-strain state of all elements of the connection. As a result, it is possible to reduce the complexity of creating a compound and its mass. The finite element method should be used for calculating critical connections with complex operating conditions. An example of calculating such a connection is considered. A comparative analysis of the results of calculating the t-joint using the arm Joint module Of the WinMachine arm system and the Abaqus finite element package is performed.


Author(s):  
V. Leont'ev ◽  
E. Kondratova ◽  
V. Kolomiychenko

traditional methods of calculation of rivet joints are based on very approximate methods of determining the forces arising in the connection. This leads to serious inaccuracies in the determination of stresses. In addition, this approach makes it impossible to calculate equivalent stresses and obtain a complete picture of the stress-strain state of the joint. All this leads to the need to increase the factor of safety and, as a consequence, increase the number or diameter of rivets, which leads to an increase in the weight of the structure and its rise in price. The proposed method of calculating the connection by the finite element method allows to determine the stresses in all elements of the connection very accurately. This makes it possible to obtain a reliable picture of the stress-strain state of all elements of the compound. As a result, it is possible to reduce the complexity of the compound and its mass by reducing the number of rivets. The finite element method should be used to calculate critical compounds with complex operating conditions. The example of calculation of such connection is considered.


2018 ◽  
Vol 8 (8) ◽  
pp. 1338 ◽  
Author(s):  
José Rojas-Sola ◽  
Eduardo De la Morena-De la Fuente

This article analyzes the first self-propelled floating dredging machine designed and executed by Agustín de Betancourt in 1810 to dredge the port of Kronstadt (Russia). With this objective, a study of computer-aided engineering (CAE) has been carried out using the parametric software Autodesk Inventor Professional, consisting of a static analysis using the finite element method, of the 3D model which is reliable under operating conditions. The results have shown that the system of inertia drums proposed by Betancourt manages to dissipate the tensions between the different elements, locating the highest stresses in the links of the bucket rosary, specifically at the point of contact between links. Similarly, the maximum displacements and the greatest deformations (always associated with these points of greater stress), are far from reaching the limits of breakage of the material used in its construction, as well as the safety coefficient of the invention, confirming that the mechanism was oversized, as was generally the case at the time. This analysis highlights the talent of the Spanish engineer and his mastery of mechanics, in an invention, the first of its kind worldwide, which served the Russian Empire for many years.


Vestnik MGSU ◽  
2020 ◽  
pp. 452-461
Author(s):  
Emil Imran Оglu Alirzaev ◽  
Marina E. Dement'eva

Introduction. One of the serious problems in the construction of underground structures in a dense urban area is the occurrence of excess deformations of the foundations of operating buildings that fall into the zone of influence of underground construction. The subject of the study was the calculated justification of the modern technology of compensatory injection. The relevance of the task is determined by the fact that the choice of the most effective protection technology should be based not only on a comparison of technological precipitation with maximum permissible values, but also on the assessment of the possibility of monitoring and controlling the movements of the foundations of buildings and structures during construction and subsequent operation. The purpose of the study was to compare various methods of protecting the foundations of existing buildings and structures and justify the selection of the most effective of them for further implementation and dissemination in the design and construction of urban underground structures. Materials and methods. On the basis of the survey data of the operated building falling into the impact zone of excavation of the pit for the construction of the installation and shield chamber of the subway, the parameters of the stress-strain state of its foundations are studied by mathematical modeling. The problem was solved by the finite element method based on the software and computer complex Z_Soil v.18.24. Results. Based on the analysis of the results of the examination of the administrative building using the finite element method, a change in the parameters of the stress-strain state of the foundations was modeled with various technologies for strengthening it. In the course of solving the geotechnical problem, it was found that the minimum impact on the foundations of the building during the construction of the pit was obtained in the method of compensatory injection. The system of criteria for making a decision on choosing an effective way to ensure the suitability of buildings in the underground construction zone for operation is substantiated. Conclusions. The results of this work can be used to justify the choice of technology for prevention and control of excess deformations of foundations. The function for calculating the volume of injected material in the Z_Soil software and computer complex can be used to justify the consumption of materials and the economic efficiency of the technological solution.


2019 ◽  
Vol 109 ◽  
pp. 00093 ◽  
Author(s):  
Olena Slashchova ◽  
Ihor Slashchov ◽  
Iryna Sapunova

The article is devoted to development of methods for geofiltration calculations with taking into account peculiarities of changes of the rock physical and mechanical properties at water saturation. Methods: mathematical modeling of geomechanical and filtration processes with the help of finite element method and laboratory and underground studies. A mathematical model was formulated for solving a problem of elasticity theory by the finite element method, which took into account peculiarities of water-saturated rocks. Pattern of stress-strain state changing in the fractured water-saturated rocks under the action of critical loads, which occurred around the preparatory roadways during their operation, were established. In order to solve the filtration problems, a bank of collected initial data on physical and mechanical properties of water-saturated rocks was processed with the help of variation coefficients, which were taken into account by the method, which assumed calculation of the model loading with critical parameters.


2016 ◽  
Vol 61 (2) ◽  
pp. 671-676
Author(s):  
Н. Dyja ◽  
А.А. Тukibay ◽  
S.A. Mashekov

Abstract To create a rational technology of cogging process and to determinate the optimal values of the angles of tilt and single reduction the stress-strain state (SSS) of the blank during cogging in the flat dies was analyzed. By using the finite element method and program MSC.SuperForge quantitative data are obtained and the basic patterns of distribution of SSS, the temperature during the simulation of tilting in flat dies with different angles of tilting and the amount of reduction were established. Sustainable experimental-industrial technology of forging of two-phase titanium alloys was developed and tested.


1982 ◽  
Vol 14 (8) ◽  
pp. 1119-1123 ◽  
Author(s):  
P. P. Gontarovskii ◽  
L. I. Gontarovskaya ◽  
G. A. Marchenko ◽  
Yu. I. Matyukhin

2021 ◽  
Vol 274 ◽  
pp. 03027
Author(s):  
Bakhodir Rakhmonov ◽  
Ismoil Safarov ◽  
Mukhsin Teshaev ◽  
Ravshan Nafasov

There is a large number of underground tunnels of various shapes located in seismic zones that need to be protected from seismic impacts. The paper considers the effect of harmonic surface waves on a cylindrical inclusion of various shapes located in a viscoelastic half-plane. The main purpose of the study is to determine the stress-strain state of the obstacle when exposed to harmonic waves. The problem is solved by the finite element method. It was found that the maximum stress concentration is allowed at long waves, and the stress concentration with increasing depth and wavelength approaches the static value of stress. The reliability of the obtained research results is confirmed by good agreement with theoretical and experimental results obtained by other authors.


Author(s):  
Н.В. Курбатова ◽  
Ю.А. Устинов ◽  
Е.С. Чумакова

На основе метода однородных решений и численным интегрированием методом конечных элементов двумерных краевых задач, с помощью которых описываются решения задач Сен-Венана о чистом изгибе и изгибе поперечной силой естественно закрученного стержня, строится решение и на его основе проводится анализ напряженно-деформированного состояния стержня прямоугольного поперечного сечения для произвольных значений относительного угла закручивания τ0.


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