scholarly journals TESTS OF LOADING STRUCTURES OF A SPECIAL ROLLING STOCK AFTER LONG OPERATION

2021 ◽  
Vol 1 (37) ◽  
pp. 5-11
Author(s):  
O. Fomin ◽  
Keyword(s):  
Service Life ◽  
Traffic Safety ◽  
Rolling Stock ◽  
Technical Diagnostics ◽  
Technical Solution ◽  
Essential Requirement ◽  
Term Operation ◽  
Strength Tests ◽  
Long Operation

Traffic safety is an essential requirement for railways. In order to ensure uninterrupted transportation of passengers and goods by rail by the enterprise of JSC "Ukrainian Railways", the task of ensuring the operation of rolling stock outside the assigned line of service remains urgent. Proceeding from this, it follows that it is necessary to carry out tests aimed at creating conditions for the operation of rolling stock while maintaining dynamic and strength characteristics. This article presents the order, scope and results of strength tests of rolling stock after long-term operation on the example of an AS1a-type railroad car. The results of the maximum stress levels, standard deviation, fatigue safety factors, the dependence of the stress level on the speed of movement are obtained. Based on the research results, a technical solution has been developed that allows using technical diagnostics methods to extend the service life of the AS1a type railroad cars after the end of the assigned service life.

STUDY OF RESIDUAL RESOURCE AND ESTABLISHMENT OF THE LIMIT LIFE OF NON-PURCHASER PASSENGER CARS OF CONSTRUCTION OF KVZ

2020 ◽  
pp. 54-62
Author(s):  
N. Radkevich ◽  
S. Sapronova ◽  
V. Tkachenko
Keyword(s):  
Service Life ◽  
Residual Life ◽  
Rolling Stock ◽  
Technical Diagnostics ◽  
Passenger Cars ◽  
Load Bearing ◽  
Metal Structures ◽  
Passenger Traffic ◽  
Long Operation ◽  
Theoretical Results

In order to ensure the uninterrupted performance of passenger traffic, the task of ensuring the operation of rolling stock outside the extended service life, including passenger cars for the carriage of passengers, remains relevant. Based on this, there is a need for comprehensive research aimed at substantiating the possibility of ensuring operation while maintaining dynamic and strength characteristics. The article examines the residual life of load-bearing metal structures of passenger cars based on the results of technical diagnostics and standard tests. It is concluded that the condition of the load-bearing metal structures of passenger cars built by the Kryukiv Carriage Plant (KСP) after long operation does not approach the limit. The obtained practical and theoretical results make it possible to extend the service life of passenger cars for the construction of KCP beyond the factory set by 41 years.

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 Road Overbridges of Car Lift Type for Crossing Railway Tracks in Densely Built-Up Areas of Modern Cities

2021 ◽  
Vol 18 (5) ◽  
pp. 90-108
Author(s):  
D. V. Efanov ◽  
V. N. Myachin ◽  
G. V. Osadchy
Keyword(s):  
Los Angeles ◽  
Traffic Safety ◽  
Road Traffic ◽  
Rolling Stock ◽  
Technical Diagnostics ◽  
Technical Solution ◽  
Road Transportation ◽  
Moving Platforms ◽  
Monitoring Zone ◽  
Alternative Sources

The theoretical prerequisites for construction of road overbridges of car lift type for crossing railways by automotive vehicles are suggested. A technical solution has been proposed that makes it possible to ensure the crossing by cars of «problem» railway crossings during periods of their long-term closure for road traffic. The same solution can be used to organise a road overbridge in other locations where there is no railway crossing. The technical solution itself is based on the use of overhead road overpasses and is a «simplified» version of the solution implemented by Elon Musk and his company in Los Angeles based on a tunnel, moving platforms and freight elevators. For development of car lift type road overbridges, computational methods of theoretical mechanics, technical diagnostics and monitoring, as well as the theory of queuing should be used to estimate the number of cars passed through it when crossings are closed. It is proposed that the structures of the overbridge should be «built-in» into the landscape, equipped with alternative sources of energy supply and technical means of control, diagnostics and monitoring of rolling stock and of location of direct intersection of automobile and railway roads (an intelligent monitoring zone). The proposed promising technical solution in the form of a road overbridge makes it possible to increase comfort of road transportation and improve traffic safety at level crossings.

Fatigue Strength and Metal Condition in the Context of Gas Turbine Buckets Life Extension

2012 ◽  
Author(s):  
Sergey A. Ivanov ◽  
Alexander I. Rybnikov
Keyword(s):  
Fatigue Strength ◽  
Service Life ◽  
Gas Turbine ◽  
Fatigue Resistance ◽  
Gas Turbines ◽  
Life Extension ◽  
Term Operation ◽  
Life Estimation ◽  
Metal Properties

Criteria for remaining life estimation and methods for enhancing fatigue resistance of heavy-duty gas turbine bucket metal are based on the analysis of changes in the structure and properties of metal after long-term operation. High-cycle fatigue (HCF) resistance is shown to be a decisive characteristic in the residual life estimation of turbine buckets after operation over 100,000 hours. The tests of the buckets from cast and wrought nickel-based alloys after long-term operation demonstrated decreasing of fatigue strength by up to 25%. The metal structure in operation undergoes notable deterioration mainly in phase redistribution. The size and configuration of metal phases are changing also. It caused the changes in metal properties. The decrease of the bucket fatigue strength correlates with the decrease of metal ductility. The reconditioning heat treatment resulted in restoring mechanical properties of metal. The fatigue resistance also increased nearly to the initial level. The influence of operational factors on bucket fatigue strength deterioration has been established. The mechanical damages on bucket airfoil may decrease the fatigue resistance. We found the correlation of endurance limit and damages depth. The procedures for metal properties recovering and buckets service life substantial extension have been developed. It has resulted in the extension of the buckets service life by up to 50% over the assigned life in gas turbines operated by Gazprom.

scholarly journals DEGRADATION DAMAGE OF REINFORCED CONCRETE FRAME IN LONG-TERM EXPLOITATION

2021 ◽  
Vol 9 (4) ◽  
pp. 11-15
Author(s):  
Mikhail Berlinov ◽  
Marina Belinova ◽  
Roman Korol ◽  
Aleksandr Tvorogov
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
Phenomenological Theory ◽  
Reinforced Concrete Frame ◽  
Term Operation ◽  
Concrete Frame ◽  
Aggressive Environment ◽  
Real Work ◽  
Combined Action

A method for calculating a reinforced concrete frame under rheological deformation conditions is proposed, taking into account degradation damage as a result of corrosion during long-term operation, reflecting their real work under the combined action of a load and an aggressive environment based on the modern phenomenological theory of deformation of an elastic-creeping body. The possibility of considering the processes of long-term deformation of reinforced concrete in conditions of long-term exploitation is shown. Analytical dependencies and a calculated example are given for the considered service life.

scholarly journals THE CONCEPT OF EXTENDING THE TERMS OF LOCOMOTIVE OPERATION

2021 ◽  
pp. 24-33
Author(s):  
Alexander Semenovich Krasheninin ◽  
Dmytro Oleksandrovych Matsegora ◽  
Y.O. Sachenko ◽  
J. S. Blokhin
Keyword(s):  
Service Life ◽  
Rail Transport ◽  
Rolling Stock ◽  
Railway Transport ◽  
Term Operation ◽  
The World ◽  
Design Loads ◽  
Standard Set ◽  
Modern Knowledge ◽  
Standard Service

Due to the reliability standard set during the design and even when it reaches orexceeds the standard service life of more than 90 % of locomotives, railway transport continues toperform its functions. Many years of experience in the operation of locomotives confirm thecorrectness of the norms laid down in the standards for their design to the design loads andindicators of dynamics and strength of load-bearing structures: the standard stock ratio (2) ensurestheir operation during the service life.(25 ... 30 years) In many countries, as part of the extension of the service life of TRS at onetime had to solve complex scientific and applied problems. For example, most recently in Europeancountries, rolling stock depreciation was up to 65% of service life. In the interaction of TRSproducers and users, the concept of repair and modernization of TRS at the facilities ofmanufacturers was adopted, and the amount of modernization depended on customer requirements.After the modernization of the extension of the service life of TRS, it could be used on certainsections of the railway or in other types of work: economic, export, shunting. In our country, thelong-term operation of the TRS of a small number of series led to the fact that the rolling stock wasalmost not renewed and the problem of extending the service life was not solved. Now difficultpolitical and environmental factors have led to the fact that after some time it will be dangerous touse rail transport. As the world and domestic experience of TRS operation shows, urgent changes inall links of the industry and operation are necessary. The resource of TRS put in production allowsto keep and maneuver in a choice of strategy of management of the maintenance of TRS. Inconnection with the aging of rolling stock and the development of the assigned service life arerelevant to the study of the original and residual resources of the structure. To do this, thestandards must be clarified and supplemented on the basis of accumulated operating experienceand taking into account modern knowledge to assess and ensure the necessary durability and safetyof operation of vehicles. Based on this, the topic of changing the system of extending the service lifeis relevant. The article considers the concept of general approaches to extending the service life oflocomotives.

Influence of bending radius on longitudinal stresses in long operation pipelines

2020 ◽  
Vol 10 (3) ◽  
pp. 234-242
Author(s):  
Robert М. Askarov ◽  
◽  
Aydar К. Gumerov ◽  
Rinat M. Karimov ◽  
Khiramagomed Sh. Shamilov ◽  
...  
Keyword(s):  
Technical Condition ◽  
Regulatory Requirements ◽  
Bend Radius ◽  
Term Operation ◽  
Mandatory Requirement ◽  
Bending Radius ◽  
New Construction ◽  
The Impact ◽  
Long Operation

Calculations of stress-strain state of pipelines are performed in accordance with the unified regulatory requirements, which do not take into account facilities operation. Thus, the limitation of minimal allowable bend radius with the value of 1000 pipe diameters (1000D) can be considered justified in relation to a new construction project, but the problem is that it is applied to all pipelines independently of its service life. At the same time the modern smart pigging technologies allow for obtaining precise data on bend radius of operated pipelines, and the diagnostics results indicate, that mandatory requirement for minimal value of 1000D frequently contradicts the actual technical condition of researched objects. The authors performed the analysis of standard formula for calculation of longitudinal stresses, considered the impact on the calculated value of its separate constituents: values of pressure, temperature difference and bend radius. The conclusion is made about the necessity for reassessment of the current regulations for scientific justification of acceptable values of pipeline longitudinal stresses. It is established, that the primary factor, which is responsible for forming the value of longitudinal stresses of the pipelines during long-term operation is the bend radius.

scholarly journals INVESTIGATION OF RESIDUAL RESOURCE OF SPECIAL RAILWAY VAGON

2021 ◽  
Vol 1 (37) ◽  
pp. 50-58
Author(s):  
N. Radkevich
Keyword(s):  
Service Life ◽  
Residual Life ◽  
Technical Diagnostics ◽  
Residual Service Life ◽  
Passenger Cars ◽  
Scientific Publications ◽  
Load Bearing ◽  
Metal Structures ◽  
Long Operation ◽  
Standard Tests

The article examines the residual life of load-bearing metal structures (NMC) of special cars for the transportation of special contingent on the basis of the results of technical diagnostics and standard tests. Most scientific publications investigate the increase in the service life of different types of passenger cars by improving their design properties. The following methods are used in the study: resetting from wedges, resource tests for impact strength, impact tests, static strength tests. On the basis of carrying out technical diagnostics and standard tests the possibility of establishment of new appointed service life of cars is defined. The residual resource was set at one of the minimum calculated values obtained by mathematical dependence to calculate the residual service life. When determining the residual resource during the standard tests, the evaluation of the fatigue resistance margin was performed taking into account the stress of the load-bearing structures of the car during the tests. It is concluded that the condition of load-bearing metal structures of special wagons for transportation of special contingent after long operation does not approach the limit. The obtained practical and theoretical results make it possible to extend the service life of special wagons for the transportation of special contingent beyond the established by the manufacturer.

scholarly journals УСТАНОВЛЕНИЕ ОГРАНИЧЕНИЙ ПО МАКСИМАЛЬНЫМ СКОРОСТЯМ ДЕСАНТИРОВАНИЯ С УЧЕТОМ ДЕГРАДАЦИИ ПРОЧНОСТНЫХ ХАРАКТЕРИСТИК МАТЕРИАЛОВ КУПОЛА ПАРАШЮТА. СООБЩЕНИЕ 2. ЗАВИСИМОСТЬ МАКСИМАЛЬНЫХ СКОРОСТЕЙ ДЕСАНТИРОВАНИЯ ОТ ДЕГРАДАЦИИ ПРОЧНОСТИ

2019 ◽  
pp. 61-68
Author(s):  
Петр Александрович Фомичев
Keyword(s):  
Initial Conditions ◽  
Maximum Load ◽  
Strength Characteristics ◽  
Fall Rate ◽  
Motion Equations ◽  
Term Operation ◽  
Strength Tests ◽  
Parachute System ◽  
The Moment

Part 2 is a continuation of Part 1 [1], which proposed the dependence of the maximum permissible loads on the parachute on the degradation coefficients of the power structure elements strength characteristics. The condition of equality of safety factors for elements after the long-term operation and during design was adopted. The results of calculating the speeds and loads on the parachute were compared with published experimental data. In particular, for the rescue parachute, calculations were made of the fall rate at the moment of the beginning of filling the dome and the maximum load, depending on the aircraft speed. The fall rate is calculated numerically using the motion equations of the dummy-parachute system with given initial conditions. This speed almost coincides with that measured experimentally. Quite satisfactory coordination takes place and for the maximum load. In accordance with the methodology, N. A. Lobanov maximum load depends on the speed at the time of the parachute full opening. This speed is largely determined by the value of the empirical generalized coefficient K. The numerical value of K should be found for a particular parachute from the condition of matching the calculated and experimentally measured loads. The analysis of maximum landing speeds flight limitations from the degradation coefficients of the structural materials strength characteristics was carried out for two cases. The first corresponds to the constancy of the time of separation from the aircraft until the introduction of the parachute dome into operation. The second corresponds to the accounting for the dependence of this time on the aircraft speed. Calculations of the dependence of the maximum allowable aircraft speed on the degradation coefficients were performed in the widest possible range of the generalized coefficients K variation for the dome and lines fabric. The spare Z-5 and landing D-5 series 2 parachutes are considered. The dependences of the maximum permissible landing speeds on the strength degradation coefficients of the framework elements of these parachutes have been established. The actual value of these coefficients must be established by means of destructive strength tests

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