scholarly journals The impact of deformation in the zone of welded joints on the force action of the rolling stock on the track

2020 ◽  
Vol 79 (1) ◽  
pp. 9-16
Author(s):  
V. S. Kossov ◽  
O. G. Krasnov ◽  
M. G. Akashev
Keyword(s):  
Welded Joints ◽  
Welded Joint ◽  
Experimental Studies ◽  
Longitudinal Direction ◽  
Local Heat ◽  
Rolling Stock ◽  
Rolling Surface ◽  
Kolmogorov Smirnov ◽  
The Impact

The causes of deformation in the zone of welded joints are considered. Authors experimentally studied changes in hardness on the rolling surface of the rail in the longitudinal and transverse profiles within the thermally affected zone of the welded joint. It is established that the hardness of the rolling surface of the rail in the longitudinal direction in the thermally affected zone of the joint is uneven and is determined by the structures arising from the effects of the thermal cycles of welding and the quality of the local heat treatment. In this case, two "low spots" are clearly traced with a decrease in hardness to 290...300 HB and with a higher hardness up to 350 HB right in the welded joint. Experimentally investigated the change in the depth of the welded joint from the implemented tonnage. At the same time with strain gauge method, using the force method developed by N. N. Kudryavtsev, continuous changes in vertical forces when the wheels move along the welded joint zone were recorded. Average values of vertical forces from loaded cars were established. Experimental distributions of vertical forces were approximated by theoretical laws according to the Kolmogorov — Smirnov matching criterion. Recommendations are given on minimizing the harmful impact of rolling stock on the track in areas of lowering welded joints.The following conclusions were made.1.            Geometry of the joint irregularity is in the form of a W-shaped deformation with an influx of metal on the receiving rail and lowering on the directing rail. The width of the upper part of the deformation varies between 160...200 mm along the axis of the rail.2.            Deformation zone of the welded joint is a source of increased dynamic impact from the wheels of the rolling stock on the elements of the upper track structure. According to the results of experimental studies it was found that the greatest increase in dynamic effects was observed from locomotive wheels up to 45..               . 70 kN, maximum values reached 180...210 kN, from the wheels of loaded freight cars the values of vertical forces increased by 35..     .45 kN, maximum values reached 145...170 kN, from the wheels of empty cars increase dynamic impacts amounted to 14...16 kN, maximum values reached 32...36 kN.

Расчетные методы оценки ударной вязкости сварных элементов с трещинами

2020 ◽  
Vol 44 (3) ◽  
pp. 22-36
Author(s):  
Keyword(s):  
Stress Intensity ◽  
Impact Strength ◽  
Welded Joints ◽  
Development Process ◽  
Welded Joint ◽  
Operating Temperature ◽  
Crack Development ◽  
Heterogeneous Structure ◽  
Critical Crack Length ◽  
The Impact

Практика показывает, что для сварных конструкций, эксплуатируемых в условиях Крайнего Севера необходимо уделять внимание работоспособности сварных соединений при низких температурах. Металл сварных соединений в процессе воздействия обработки изменяет свои свойства, снижается ударная вязкость, образуется гетерогенная структура с большой степенью разнозернистости. Чтобы оценивать и иметь возможность правильно контролировать термическое воздействие и последствия сварочного процесса, требуется решить задачу аналитического определения ударной вязкости для всех зон сварного соединения. В настоящей статье представлен инженерный метод оценки ударной вязкости, применимый для любой зоны сварного соединения, в которой имеется острый или особый концентратор напряжений – трещина. Разработанный аналитический метод расчета ударной вязкости отражает качественную и количественную картину взаимосвязи структурно-механических характеристик и работы развития трещины в диапазоне температур 77…300 К. Предложенная схематизация зависимости критического коэффициента интенсивности напряжений от температуры позволила найти коэффициенты, характеризующие свойства материала, и выполнить расчеты изменения предела текучести и предела прочности от температуры эксплуатации. Построены графики зависимости работы развития трещины от температуры эксплуатации для сталей 15ГС и 17ГС, сравнение которых с экспериментальными данными показывает удовлетворительное согласование. Найдено, что при напряжениях предела выносливости отношение работы развития трещины к критической длине трещины постоянно, не зависит от температуры и для сталей 15ГС и 17ГС равно около 10. Ключевые слова: ударная вязкость, работа разрушения, коэффициент интенсивности напряжений, трещина, феррито-перлитная сталь, зона термического влияния. For welded structures under operation in the Far North, attention must be paid to the performance of welded joints at low temperatures. The properties of metal of welded joints are changed in the process of treatment, its toughness decreases, and a heterogeneous structure with a large range of different grain sizes is formed. In order to evaluate and be able to correctly control the thermal effect and the consequences of the welding process, it is necessary to solve the problem of analytical determination of impact strength for all zones of the welded joint. The paper presents an engineering method for evaluation of the impact strength applicable to any area of the welded joint in which there is a sharp or super sharp stress concentrator – a crack. The developed analytical method for calculating the impact strength reflects a qualitative and quantitative codependency of structural and mechanical characteristics and the process of crack development in the temperature range of 77–300 K. The proposed schematization of dependence of the critical coefficient of stress intensity on the temperature made it possible to find coefficients characterizing the properties of the material and to perform calculations of changes in yield strength and tensile strength on operating temperature. Graphs of the crack development process dependency on the operating temperature for 15ГС and 17ГС steels were constructed, and their comparison with experimental data displays satisfactory agreement. It was found that at endurance limit stresses, the ratio of the crack development process to the critical crack length is constant, non-dependent on temperature, and is equal to 10 for 15ГС and 17ГС steels. Keywords: impact strength, fracture work, stress intensity factor, crack, ferrite-pearlite steel, heat affected zone, steel tempering.

scholarly journals Impact of eating disorders on paid or unpaid work participation and performance: a systematic review and meta-analysis protocol

2022 ◽  
Vol 10 (1) ◽  
Author(s):  
Fatima Safi ◽  
Anna M. Aniserowicz ◽  
Heather Colquhoun ◽  
Jill Stier ◽  
Behdin Nowrouzi-Kia
Keyword(s):  
Systematic Review ◽  
Eating Disorders ◽  
Meta Analysis ◽  
Experimental Studies ◽  
Work Participation ◽  
Unpaid Work ◽  
Cochrane Library ◽  
And Performance ◽  
The Impact

Abstract Background Eating disorders (ED) can reduce quality of life by limiting participation and performance in social and occupational roles, including paid or unpaid work. The association between ED pathologies and work participation and performance must be well understood to strengthen vocational rehabilitation programmes and prevent occupational disruptions in the ED population. The aims of this study are: (1) to examine the degree of association between ED pathologies and work participation and performance in 15-year-olds and older; (2) to highlight the specific ED symptoms that are most correlated with changes in work performance and participation; (3) to compile the most common metrics and assessments used to measure work participation and performance with ED. Methods Medline, Embase, CINAHL, Web of Science, PsycINFO, and Cochrane Library will be searched for observational and experimental studies that meet the following criteria: (1) a clinical sample of typical or atypical ED; (2) paid or unpaid employment or training; (3) an association between ED pathologies and work participation or performance. Unpublished data will also be examined. Title and abstract, and full-text screening will be conducted in duplicate. Risk of bias and quality of evidence assessments will be completed. A random-effect meta-analysis will be performed. Discussion This synthesis can clarify knowledge and gaps around the impact of ED on work functioning, thereby allowing better evaluation, improvements and development of current workplace assessments, interventions, and policies. Trial registration The registration number for this systematic review on PROSPERO is CRD42021255055.

scholarly journals Energy Saving for the Suburban Rolling Stock

2018 ◽  
Vol 7 (4.3) ◽  
pp. 361 ◽  
Author(s):  
Andriy Sumtsov ◽  
Anatoliy Falendysh ◽  
Nataliya Chyhyryk ◽  
Oleg Vasilenko
Keyword(s):  
Energy Efficiency ◽  
Thermal Imaging ◽  
Energy Savings ◽  
Local Heat ◽  
Heat Losses ◽  
Rolling Stock ◽  
Passenger Compartment ◽  
Sealing Layer ◽  
Railway Rolling Stock

This article is concerned with the problem of energy savings and rise of comfortableness of railway rolling stock. Done analysis has shown the insufficient paying attention to the energy efficiency of suburban rolling stock. In particular, to the problem of heat comfort for passengers. For this purpose, a procedure was carried out for the thermal audit of electric trains, taking into account the prevailing array of required indicators. To determine the sites of local heat losses, there was done the thermal-imaging inspection of the electrical train ER2 series during which it was determined the local sites of heat losses and entry of cold air. Besides the passenger compartment, there were inspected the outer body liner and driver's cabin. As a result of inspection of driver's cabin, it was found the bad quality of a sealing layer for side small windows from one side. On the basis of inspection, the recommendations for elimination of found irregularities were developed.   

scholarly journals Consideration of quality change of railway transport maintenance operations in managing costs of goods transport

2018 ◽  
Vol 239 ◽  
pp. 03005
Author(s):  
Lidia Shkurina ◽  
Eugenia Maskaeva ◽  
Stanislav Maskaev
Keyword(s):  
Cost Management ◽  
Rolling Stock ◽  
Market Demand ◽  
Railway Transport ◽  
Quality Change ◽  
The Cost ◽  
The Impact ◽  
Financial Result ◽  
Freight Market

the authors reviewed the quality of operational work of railway transport in the cost management system, presented methods for assessing the impact of the quality of rolling stock on the current costs of transportation activities, considered the issues of the impact of the quality of operational work on the formation of freight market demand and of financial result of the transport company - the owner of infrastructure and traction rolling stock, represented methods of assessing financial and economic efficiency of improving the quality of operational work for the company - a participant of the freight market.

scholarly journals Selected Properties of the Surface Layer of C45 Steel Parts Subjected to Laser Cutting and Ball Burnishing

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3429 ◽  
Author(s):  
Agnieszka Skoczylas ◽  
Kazimierz Zaleski
Keyword(s):  
Surface Layer ◽  
Residual Stresses ◽  
Laser Cutting ◽  
Experimental Studies ◽  
Hardened Layer ◽  
Ball Burnishing ◽  
Absolute Value ◽  
The Impact ◽  
Compressive Residual Stresses

In this article, we report the results of experimental studies on the impact of ball burnishing parameters on the roughness, microstructure and microhardness of the surface layer of laser-cut C45 steel parts. We also analysed the distribution of residual stresses generated in the surface layer of these parts. Laser-cut parts often require finishing to improve the quality of their surface. The tests performed in this study were aimed at assessing whether ball burnishing could be used as a finishing operation for parts of this type. Ball burnishing tests were performed on an FV-580a vertical machining centre using a mechanically controlled burnishing tool. The following parameters were varied during the ball burnishing tests: burnishing force Fn, path interval fw and the diameter of the burnishing ball dn. Ball burnishing of laser-cut C45 steel parts reduced the surface roughness parameters Sa and Sz by up to 60% in relation to the values obtained after laser cutting. Finish machining also led to the reorganization of the geometric structure of the surface, resulting in an increase in the absolute value of skewness Ssk. This was accompanied by an increment in microhardness (maximum microhardness increment was ΔHV = 95 HV0.05, and the thickness of the hardened layer was gh = 40 µm) and formation of compressive residual stresses in the surface layer.

scholarly journals Influence of welding method on microstructural creation of welded joints  

2011 ◽  
Vol 57 (Special Issue) ◽  
pp. S50-S56 ◽  
Author(s):  
P. Čičo ◽  
D. Kalincová ◽  
M. Kotus
Keyword(s):  
Welded Joints ◽  
Arc Welding ◽  
Welded Joint ◽  
Gas Metal Arc Welding ◽  
Structural Phase ◽  
Welding Parameters ◽  
Welding Method ◽  
Welding Technology ◽  
Metal Arc Welding

This paper is focused on the analysis of the welding technology influence on the microstructure production and quality of the welded joint. Steel of class STN 41 1375 was selected for the experiment, the samples were welded by arc welding including two methods: a manual one by coated electrode and gas metal arc welding method. Macro and microstructural analyses of the experimental welded joints confirmed that the welding parameters affected the welded joint structure in terms of the grain size and character of the structural phase.

Features of the Heating Process in Ultrasonic Welding of Polycarbonate Products under Independent Pressure

2020 ◽  
pp. 54-62
Author(s):  
S.S. Volkov ◽  
A.L. Remizov ◽  
A.S. Pankratov
Keyword(s):  
Welded Joints ◽  
Welded Joint ◽  
Welding Process ◽  
Ultrasonic Welding ◽  
Heating Process ◽  
Mechanism Of Formation ◽  
High Quality ◽  
Acoustic Contact ◽  
Welding Pressure

This paper presents a mechanism of formation of a hard-to-weld polycarbonate joint by ultrasonic welding. The method utilizes internal and external friction occurring in the welded joint area on abutting surfaces due to shear vibrations of the end of the upper part relative to the lower part. A layer of the heated welded material is formed, localized by thickness, in which predominant absorption of the ultrasonic vibrations occurs, which allows one to obtain high-quality and durable welded joints without significant deformation due to the concentration of thermal energy in the welding zone. The effect of independent welding pressure on the strength of the welded joint of polycarbonate is considered. A new method of ultrasonic welding under the conditions of independent pressure is proposed. The method consists of dividing the static welding pressure into two components: the pressure of the acoustic contact in the zone of contact of the waveguide with the product, and the welding pressure that compresses the welded products, with the latter component being lower than the former. In order to obtain high-quality welded joints made of polycarbonate and to prevent displacement of the welded edges during the welding process relative to each other, a special preparation of the welded edges is developed, which allows one part to be moved vertically relative to the other during the welding process. It is established that the quality of welding depends on the speed of movement and the angle of cutting the edges.

scholarly journals Fuzzy C-Means Partition Cluster Analysis and Validation Studies on a Subset of CiteScore Dataset

2019 ◽  
Vol 8 (9S3) ◽  
pp. 105-107
Keyword(s):  
Cluster Analysis ◽  
Laser Welding ◽  
Validation Studies ◽  
Welded Joint ◽  
Experimental Studies ◽  
Pulsed Laser ◽  
Welding Process ◽  
Pulsed Laser Welding ◽  
Fuzzy C Means

The article deals with promising areas of application of pulsed laser welding for products made of silver-based alloys. The results of experimental studies to improve the quality of the welded joint and the efficiency of the welding process with the use of activated absorption additives are presented

scholarly journals IMPROVEMENT OF THE STRUCTURAL LAYOUT OF POTATO PLANTERS’ COULTER GROUP

2021 ◽  
pp. 81-90
Author(s):  
Alexey Semenovich Dorokhov ◽  
Andrey Grigoryevich Ponomarev ◽  
Vitaly Nikolaevich Zernov ◽  
Sergey Nikolaevich Petukhov ◽  
Alexander Gennadievich Aksenov ◽  
...  
Keyword(s):  
Experimental Studies ◽  
Acute Angle ◽  
Sharp Angle ◽  
Maximum Extent ◽  
Automatic Maintenance ◽  
Potato Planter ◽  
Growing Conditions ◽  
The Stability ◽  
The Impact

Structural layouts of coulters and their groups in potato planters are justified in the article based on the morphological features of the potato plant, its requirements for growing conditions and ensuring the quality of the planting process. The purpose of coulter groups is to form a bed for placing tubers with a loose layer of soil in 5-8 cm and sealing them with loosened soil to a certain depth. To substantiate the type of potato planter coulters that meet the requirements for potato growing conditions to the maximum extent possible, optimize the parameters of coulter groups that automatically ensure the stability of the coulter travel depth when imitating irregularities of the field microrelief. A comparative analysis of the impact on the soil of the most common anchor coulters with a blunt angle of soil entry and a sharp angle with an individual floating suspension is given, and indicators of the quality of their operation are described. It was found that coulters with an individual floating suspension and an acute angle of soil entry meet the requirements for potato growing conditions to the maximum extent possible. In order to ensure travel stabilization of such a coulter at a given depth when imitating field irregularities, a version of the coulter group has been developed that provides automatic correction of the coulter's angle of attack when changing its travel depth. Experimental studies have optimized the parameters of the coulter suspension that ensure automatic imitation of field microrelief irregularities up to 20 cm deep within the initial requirements for potato planting machines. Coulters with an individual floating suspension and a sharp angle of soil entry most fully meet the requirements for potato growing conditions to the maximum extent possible. A coulter group with a suspension aspect ratio of 150:200:400:400 cm and an acute angle of coulter entry into the soil provides automatic maintenance of the set coulter travel depth within the initial requirements (±2 cm) for irregularities in the field microrelief of up to 200 mm. In this case, the bottom and walls of the furrow are not compacted.

scholarly journals Analysis of Selected Properties of Welded Joints of the HSLA Steels

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1301 ◽  
Author(s):  
Ivan Miletić ◽  
Andreja Ilić ◽  
Ružica R. Nikolić ◽  
Robert Ulewicz ◽  
Lozica Ivanović ◽  
...  
Keyword(s):  
Impact Toughness ◽  
Welded Joints ◽  
Welded Joint ◽  
High Strength ◽  
Hardness Distribution ◽  
Micro Hardness ◽  
Hsla Steels ◽  
Applied Technology ◽  
Welding Procedure ◽  
The Impact

This paper presents research of the impact toughness and hardness distribution in specific zones of a ‘single V’butt multiple-pass welded joints of the high-strength low-alloyed steels. Obtained values of the impact toughness are analyzed in correlation with a microstructure in specific zones of the welded joint, together with the micro hardness distribution found in the related zones. Based on the carried out analysis and results obtained in experiments, the applied technology of welding was evaluated. The original conclusions on influence of the selected welding procedure manual metal arc (MMA) for the root passes and metal active gas (MAG) for the filling and covering passes) on impact toughness of the high-strength low-alloyed steels are drawn. The paper also presents discussion on the valid standards and recommendations related to welding of those steels, from the aspect of applications in design of steel welded constructions.

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