scholarly journals DESIGN AND CONSTRUCTION OF LINEAR MAIN PIPELINE ON WATER-LOGGED GROUNDS

2020 ◽  
Vol 22 (6) ◽  
pp. 167-176
Author(s):  
V. I. Khizhnyakov ◽  
A. V. Negodin ◽  
V. A. Shelkov ◽  
A. N. Toz
Keyword(s):  
Temperature Difference ◽  
Strain State ◽  
Design Stage ◽  
Main Pipeline ◽  
Axial Loads ◽  
Stress Strain ◽  
Stress Strain State ◽  
Main Pipelines ◽  
Buckling Stability ◽  
Design And Construction

The paper shows that the linear segments of the main pipelines laid on water-logged grounds are characterized by the floating parts 150–300 m long, with arch blowouts with a deflection of 1.0–1.5 m. This occurs due to the vertical axial loads and the temperature difference. The buckling stability of the floating part is calculated for the pipeline laid in a bog. It is shown that the loss of the buckling stability in the form of the floating parts and arch blowout can be explained by the fact that the project on the water-logged ground construction has no the analysis of the buckling stability under axial loads with regard to the topography of the trench bottom that describes the stress-strain state of the pipeline. At a design stage, it is necessary to conduct more detailed surveys on the pipeline laying with regard to the trench profile in calculating the pipeline buckling stability on water-logged grounds.

MODELING OF THE STRESS-STRAIN STATE OF A TRANSPORT TUNNEL UNDER LOAD AS A MEASURE TO REDUCE OPERATIONAL RISKS TO TRANSPORTATION FACILITIES

2020 ◽  
Vol 3 (8) ◽  
pp. 28-34
Author(s):  
N. V. IVANITSKAYA ◽  
◽  
A. K. BAYBULOV ◽  
M. V. SAFRONCHUK ◽  
◽  
...  
Keyword(s):  
Strain State ◽  
Moving Load ◽  
Element Model ◽  
Transport Infrastructure ◽  
Design Stage ◽  
Surface Load ◽  
Stress Strain ◽  
Stress Strain State ◽  
Operational Risks ◽  
Von Mises

In many countries economic policy has been paying increasing attention to the modernization and development of transport infrastructure as a measure of macroeconomic stimulation. Tunnels as an important component of transport infrastructure save a lot of logistical costs. It stimulates increasing freight and passenger traffic as well as the risks of the consequences of unforeseen overloads. The objective of the paper is to suggest the way to reduce operational risks of unforeseen moving load by modeling of the stress-strain state of a transport tunnel under growing load for different conditions and geophysical parameters. The article presents the results of a study of the stress-strain state (SSS) of a transport tunnel exposed to a mobile surface load. Numerical experiments carried out in the ANSYS software package made it possible to obtain diagrams showing the distribution of equivalent stresses (von Mises – stresses) according to the finite element model of the tunnel. The research results give grounds to assert that from external factors the stress state of the tunnel is mainly influenced by the distance to the moving load. The results obtained make it possible to predict in advance the parameters of the stress-strain state in the near-contour area of the tunnel and use the results in the subsequent design of underground facilities, as well as to increase their reliability and operational safety. This investigation gives an opportunity not only to reduce operational risks at the design stage, but to choose an optimal balance between investigation costs and benefits of safety usage period prolongation.

scholarly journals SIMULATION OF A FLOATING BOLLARD OF A SHIP LOCK BY THE FINITE ELEMENT METHOD

2021 ◽  
Vol 1 (63) ◽  
pp. 5-12
Author(s):  
Yong Zhang ◽  
◽  
I. Sydorenko ◽  
I. Prokopovych ◽  
Yunxuan Zhang ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Strain State ◽  
Elastic Beam ◽  
Design Stage ◽  
The Finite Element Method ◽  
Stress Strain ◽  
Stress Strain State ◽  
Ship Lock ◽  
Element Method

One of the main elements of the lock’s mooring equipment is the floating bollard. Failure of this element of the mooring equipment always leads to great difficulties in organizing ship passes in the lock, in terms of the arrangement of vessels in the lock chamber and the forced withdrawal of locks from work to bring the floating bollards into working condition. Therefore, the analysis of the performance of this element, both at the design stage and during operation, taking into account various options for its loading under the action of changing external conditions, is an urgent task. The article presents the results of a study of one of the structures of a floating bollard of a ship’s lock, which is in real operation. The studies were carried out using the finite element method, in which 3D modeling of the device under consideration was carried out and its stress-strain state was analyzed under various loading options, taking into account the dynamics of mooring operations and weather conditions. A comparative analysis of the created finite element model of the device under consideration with its simplified model in the form of an elastic beam system with a uniform cross section is carried out. A graphic interpretation of the results of the analysis of the stress-strain state of the device under consideration is given, in which the most loaded structural elements are distinguished. The identified location of the places of the largest stress-strain state is proposed to be used as a theoretical basis for the deployment of sensors of the system for alerting the state of the loading of the floating bollard of the ship lock.

scholarly journals ANALYSIS OF THE STRESS-STRAIN STATE OF AN ASYNCHRONOUS MOTOR WITH A SHORT-CIRCUITED ROTOR UNDER AXIAL LOADS

2021 ◽  
Author(s):  
Maksim Kolesnik ◽  
Sergey Ivanov
Keyword(s):  
Strain State ◽  
Asynchronous Motor ◽  
Direct Analysis ◽  
Linear Displacement ◽  
The Finite Element Method ◽  
Axial Loads ◽  
Stress Strain ◽  
Stress Strain State ◽  
Asynchronous Motors ◽  
Comparative Description

A comparative description of the most popular and professional 3D modeling packages using the finite element method in solving problems is given. The choice of using the SolidWorks Simulation package at this stage of research is justified. Its main advantages are given. A 3D model of a real functioning asynchronous motor has been designed and modified to perform linear displacement operations. A static analysis of the strength of an asynchronous motor with linear displacement of the actuator using the plug-in module SolidWorks Simulation was performed. A direct analysis of the obtained result of the stress-strain state of the engine is carried out. Conclusions are drawn about its suitability to work with axial loads. The main directions of subsequent research of asynchronous motors with a short-circuited rotor under axial loads are determined.

Strain Stress Model of the Rail with Crack in its Head and Estimation of its Operational Lifetime

2019 ◽  
Vol 970 ◽  
pp. 177-186
Author(s):  
Vitaliy V. Muravev ◽  
Kirill A. Tapkov ◽  
Ludmila V. Volkova ◽  
Andrei V. Platunov
Keyword(s):  
Temperature Difference ◽  
State Standard ◽  
Strain State ◽  
Stress Strain ◽  
Stress Strain State ◽  
Rolling Surface ◽  
Operational Lifetime ◽  
Standard Value ◽  
Strain Stress ◽  
Gost State Standard

The most common reason of the fatigue crack appearance is the presence of stresses in the rail. The process of stress strain state simulation for the R65 rail is presented in the paper. Values of residual stresses were modeled and chosen to be maximum allowed by GOST (State Standard): -77 MPa in the rail head, -125 MPa in the web and 106 MPa in rail foot. These stresses match the value-77 MPa measured by the acoustoelastic method from the center of the rolling surface of the rail. The influence of the crack at the highest level of the stress strain state was studied in cases of the maximum train load and its absence. According to results of modeling, stresses in the sharp edge of the crack can exceed the lowest acceptable by GOST (State Standard) value of the yield strength by more than 5 times in case of the presence of the train load. In case of the absence of the train load, the crack does not have a significant influence on the stress strain state. The modelling process was also used to study the influence of the installation temperature difference on the operational lifetime of the rail. The paper presents the description of the influence between the installation temperature difference and the crack initiation. According to modeling results and the rail defect catalogue, rails with the lowest acceptable mechanical characteristics are prohibited to be used after 300∙109 kg and higher tonnage.

scholarly journals ENSURING THE REQUIRED LEVEL OF RELIABILITY DURING THE DESIGN STAGE OF -LATTICED SHELLS WITH A LARGE OPENING

2015 ◽  
Vol 21 (3) ◽  
pp. 282-289 ◽  
Author(s):  
Yevgen Gorokhov ◽  
Volodymyr Mushchanov ◽  
Iurii Pryadko
Keyword(s):  
Strain State ◽  
Design Stage ◽  
Stress Strain ◽  
Static Loads ◽  
Stress Strain State ◽  
Long Span ◽  
Upper Limits ◽  
Fundamental Research ◽  
Large Opening

The article describes the design technique, which is based on determination of numerical parameters pertaining to reliability of long-span latticed roofs with a large opening formed using the system made of rigid threads. The suggested algorithm is based on experimental and fundamental research focused on the stress/strain state of a spatial roof model and the operation of design combination of loads. It suggests a solution to a series of problems: determining rational geometric parameters for a structure; obtaining corresponding rigid characteristics of the principal load-bearing members; determining the trajectory of member failure for a typical shell structure with a resulting estimation of stress/strain state of a structure; determining numerical parameters of reliability of a designed structure (determining the lower and upper limits of reliability). The proposed algorithm is limited by static loads and state requirements on strength limits. The example of a design for a spatial latticed shell formed using the system of flexurally stiff threads has been given according to the above-described algorithm.

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