Factors Causing Reduction in the Bearing Capacity of Hydraulic Turbine Structural Elements in the Course of Long-Term Operation

Vestnik MEI ◽  
2017 ◽  
pp. 12-19
Author(s):  
Evgeniya V. Georgievskaya ◽  
Keyword(s):  
Bearing Capacity ◽  
Hydraulic Turbine ◽  
Structural Elements ◽  
Term Operation

scholarly journals КОЭФФИЦИЕНТЫ ДЕГРАДАЦИИ ПРОЧНОСТИ СИЛОВЫХ ЭЛЕМЕНТОВ КУПОЛА ПАРАШЮТА ПОСЛЕ ДЛИТЕЛЬНОЙ ЭКСПЛУАТАЦИИ ИЛИ ХРАНЕНИЯ

2019 ◽  
pp. 62-71
Author(s):  
Петр Александрович Фомичев ◽  
Игорь Михайлович Сила
Keyword(s):  
Service Life ◽  
Breaking Load ◽  
Strength Characteristics ◽  
Test Results ◽  
Structural Elements ◽  
Term Operation ◽  
Lower Confidence ◽  
Strength Tests ◽  
Normal Law

The technique of processing the test results to the destruction of samples cut from slings and dome fabric after prolonged use or storage of the parachute is described. The normal law of load distribution before failure is adopted.It is proposed to find the minimum breaking load as the lower confidence limit depending on the number of tested samples and a confidence probability of 0.99.The results of strength tests of samples from the parachutes of the landing D-5 series 2 of 1983, the spare Z-5 of 1984, and the rescue S-5K series 2 of 1989 are presented.A total of 301 samples were tested, including 54 samples from slings D-5, 48 samples from slings Z-5 and S-5K, samples from fabrics of domes on the base and weft. Samples from slings were cut out at the edge of the dome, in the middle, at the arc buckles.Fabric samples were cut radially from the top to the edge of the dome. The dependence of the strength characteristics on the location of the samples along the length of the slings or the dome panel has not been established.There are no gross errors in the tests according to the Grubbs criterion.The strength degradation coefficients of the slings and fabrics of the domes are determined as the ratio of the breaking load after long-term operation or storage to the initial values adopted during the design.The proximity of the degradation coefficients of slings and dome fabrics was noted. Based on the set of test results in order to obtain the minimum values of the degradation coefficients, a linear dependence on the life of the parachute is established.This period should be counted from the year the parachute was made.The dependence of the minimum degradation coefficients (maximum degradation) on the service life makes it possible to assess the drop in the strength characteristics of the structural elements with increasing service life. This dependence allows you to predict the maximum allowable landing speed when deciding on the extension of the life of the parachute.

scholarly journals Restoring bearing capacity of fiberglass overwrap of aviation cylinders for storing liquids, gases and fire – extinguishing compounds

2021 ◽  
Vol 5 (1) ◽  
pp. 70-78
Author(s):  
Roman Kachmar ◽  
Gheorghij Kryvov ◽  
Dmytro Jermolin ◽  
Valerij Matvijenko ◽  
Boris Karpinos ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Stressed Condition ◽  
Technological Equipment ◽  
Technological Parameters ◽  
Term Operation ◽  
Fire Extinguishing ◽  
Fiberglass Fabric ◽  
Numerical Research

The article proposes a methodology for numerical research of stressed condition (SC) of aviation cylinders for storing liquids, gases and fire-extinguishing compounds in order to determine structural and technological parameters (STP) for repairing of defects in their fiberglass overwraps (FO) due to long-term operation and mechanical damages. Structural and technological parameters for repair of FO using fiberglass bandages and fiberglass fabric patches аre determined on the examples of numerical research of SC of cylindrical and spherical cylinders. According to developed methodology, STP for repairing of FO of cylinders make possible to select modern materials and technological equipment.

scholarly journals Prevention of uncontrolled progressive collapse of a high-rise brick building

2018 ◽  
Vol 143 ◽  
pp. 01006
Author(s):  
Oleg Pakhmurin
Keyword(s):  
Climatic Factors ◽  
Progressive Collapse ◽  
Operational Reliability ◽  
Structural Elements ◽  
Load Bearing ◽  
Term Operation ◽  
High Rise ◽  
Failure Diagram ◽  
Stone Walls

In recent years, there is a trend towards increasing the failure rate of buildings and structures as a result of unforeseen situations. This study is aimed at assessing the operational reliability of the structure to prevent emergencies and progressive collapse. The behavior of structures affected by various factors was analyzed. The operational condition of a building with stone walls and a rigid structural frame constructed in the middle of the 20th century was considered. By means of a detailed instrumental examination, effects of long-term operation, climatic factors and violations during construction on the serviceability of the building were analyzed. Geotechnical conditions of the site were investigated. Necessary re-calculations for load-bearing structural elements and foundations were carried out. An expected failure diagram for vertical load-bearing structures of the building is presented. Proposals for preventing progressive collapse were developed on the basis of the author's technique.

Novel polymer materials for protecting crew and structural elements of orbital station against microorganisms attack throughout long-term operation

2009 ◽  
Vol 64 (1) ◽  
pp. 36-40 ◽  
Author(s):  
Yu. Savelyev ◽  
A. Rudenko ◽  
L. Robota ◽  
E. Koval ◽  
O. Savelyeva ◽  
...  
Keyword(s):  
Polymer Materials ◽  
Structural Elements ◽  
Orbital Station ◽  
Term Operation

scholarly journals LOADING OF STRUCTURAL ELEMENTS OF LARGE-SIZED ROTATING AGGREGATES DURING LONG-TERM OPERATION

2018 ◽  
Vol 1 (50) ◽  
pp. 25-35
Author(s):  
A. O. Kychma ◽  
R. Ya. Predko
Keyword(s):  
Structural Elements ◽  
Skew Angle ◽  
Kinematic Parameters ◽  
Turn Angle ◽  
Drive Mechanism ◽  
Term Operation ◽  
Electromechanical Drive ◽  
Long Time ◽  
Practical Recommendations

Methods for determining the teeth total skew angle crown engagement considering errors from manufacturing and from mutual arragement of pinion and coronal wheel of an open gearing are implemented. On the basis of experimental data, the possible range of the total skew angle has been determined for different conditions under which large-sized rotating aggregates are operated. Algorithm and techniques of calculation operated for a long time rotating aggregates during transitive and steady-state regimes of electromechanical drive mechanism operation, non-uniformity of the turn angle of the coronal wheel were considered. Practical recommendations for design improvement of an open gearing and for a system of kinematic parameters adjustment of large-sized rotating aggregates drive mechanism are suggested.

scholarly journals The use of nanomodified concrete in construction of high-rise buildings

2018 ◽  
Vol 33 ◽  
pp. 02065
Author(s):  
Sergei Prokhorov
Keyword(s):  
Electrical Conductivity ◽  
Structural Strength ◽  
Concrete Structures ◽  
Real Life ◽  
Design Stage ◽  
Structural Elements ◽  
Term Operation ◽  
High Rise

Construction is one of the leading economy sectors. Currently, concrete is the basis of most of the structural elements, without which it is impossible to imagine the construction of a single building or facility. Their strength, reinforcement and the period of concrete lifetime are determined at the design stage, taking into account long-term operation. However, in real life, the number of impacts that affects the structural strength is pretty high. In some cases, they are random and do not have standardized values. This is especially true in the construction and exploitation of high-rise buildings and structures. Unlike the multi-storey buildings, they experience significant loads already at the stage of erection, as they support load-lifting mechanisms, formwork systems, workers, etc. The purpose of the presented article is to develop a methodology for estimating the internal fatigue of concrete structures based on changes in their electrical conductivity.

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