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Tytuł:
Controlling the State of Residual Stresses in Railway Rails by Modifying Pass Design of Straightening Rollers
Autorzy:
Żak, Sylwester
Woźniak, Dariusz
Powiązania:
https://bibliotekanauki.pl/articles/2203704.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
railway rail
residual stresses
straightening process
straightening rollers
strain gauge method
Opis:
The paper presents a summary of research on the possibility of influencing the state of residual stresses in railway rails by changing the pass design of vertical and horizontal straightener rollers and optimising their distribution on the rail perimeter. The presented results are devoted to the influence of profiled rollers on the level of residual stresses. A wide range of theoretical considerations were carried out based on the use of the finite element method using the commercial Forge software package. In order to verify the results of the theoretical considerations most reliably, a series of “in situ” experiments were conducted in industrial conditions on an existing production line. The tests were carried out on 120 meters long 60E1 railway rails. A significant reduction in the level of residual stresses compared to the standard requirements was achieved.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 1; 57--70
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Influence of Changes in Roll Pass Design on the State of Residual Stresses in Railway Rails - Summary
Autorzy:
Żak, Sylwester
Woźniak, Dariusz
Powiązania:
https://bibliotekanauki.pl/articles/27313872.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
railway rail
residual stresses
pass design of roll grooves
pass design of straightening rollers
strain gauge method
Opis:
The article presents the results of the last stage of work on the impact of changes in the roll pass design on the state of residual stresses in railway rails. The discussed stage includes the summary of industrial experiments of rolling 60E1 rails with a length of 120 meters using a modified pass design of roll grooves. The rolling technology has been deeply modified, ranging from the finishing stand, through the pre-finishing stand, to the semi-finishing stand. The rails in this experiment were cooled using standard cooling technology and then straightened using innovative vertical straightener shaped rollers. Residual stresses were tested using the strain gauge method and the hole-drilling strain gauge method by drilling a hole in the rail axis and at a distance of 14 millimetres from its axis. The resulting tensile stresses in the rail foot were reduced to an average level of less than 43% in relation to the requirements of the EN13674-1 standard.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 2; 439--446
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The significance of the absorption of EU funds in the socio-economic development of the subregions of Poland, the Czech Republic, and Slovakia
Znaczenie absorpcji funduszy Unii Europejskiej w rozwoju społeczno-gospodarczym podregionów Polski, Czech i Słowacji
Autorzy:
Spychała, Marcin
Powiązania:
https://bibliotekanauki.pl/articles/36412654.pdf
Data publikacji:
2023
Wydawca:
Uniwersytet Rzeszowski. Wydawnictwo Uniwersytetu Rzeszowskiego
Tematy:
fundusze unijne
rozwój społeczno-gospodarczy
miernik syntetyczny
EU funds
socio-economic development
synthetic gauge
Opis:
Within the EU cohesion policy, higher and lower developed regions, taking into account only GDP per capita, are subcategorised. Based on that, areas qualifying for obtaining support from aid programs of the general EU budget are established. The aim of the article is to attempt to specify the co-dependency between the absorption of EU funds and the changes in the level of socio-ceonomic development in the regional dimension. The research was conducted at the level of 95 NUTS-3 units in Poland, the Czech Republic, and Slovakia in three stages. In the first stage, the level of the development of the subregions in Poland, the Czech Republic, and Slovakia is exhibited, subcategorising three factors of that growth based on 31 indicators: “the society”, “the economy”, or “the natural environment”. In the second stage, the variation in the absorption of EU funds in the researched units is demonstrated. In the third stage, the co-dependencies between the extent of the absorption and the changes in the development within the arrangement of the factors of that development are specified. In the article, a hypothesis is verified according to which the absorption of the EU funds impacted, above all, the development of “the economy” component. As a result of the examination conducted, it has been concluded that the absorption of EU funds impacted the changes in the level of the development of the “economy” sector to the largest extent. It confirms the proper direction of the EU fund intervention, which was made accessible above all to the benefit of the development of that factor.
W ramach polityki spójności UE wyodrębnia się regiony lepiej i gorzej rozwinięte biorąc pod uwagę jedynie wartość PKB per capita. Na tej podstawie ustala się m.in. obszary kwalifikujące się do uzyskania wsparcia z programów pomocowych budżetu ogólnego UE. Celem artykułu jest próba określenia zależności pomiędzy absorpcją funduszy unijnych a zmianami poziomu rozwoju społeczno-gospodarczego w ujęciu regionalnym. Badania przeprowadzono na poziomie 95 jednostek NUTS-3 w Polsce, Czechach i Słowacji w trzech etapach. W pierwszym etapie określono poziom rozwoju podregionów w Polsce, Czechach i Słowacji, wyodrębniając na podstawie 31 wskaźników trzy czynniki tego rozwoju: „społeczeństwo”, „gospodarkę” oraz „środowisko naturalne”. W drugim etapie przedstawiono zróżnicowanie absorpcji funduszy unijnych w badanych jednostkach. W trzecim etapie określono zależności pomiędzy wielkością absorpcji a zmianami poziomu rozwoju w układzie czynników tego rozwoju. W artykule postanowiono zweryfikować hipotezę, według której absorpcja funduszy unijnych wpłynęła przede wszystkim na rozwój składowej „gospodarka”. W rezultacie przeprowadzonego badania stwierdzono, że absorpcja funduszy unijnych w największym stopniu wpłynęła na zmiany poziomu rozwoju „gospodarki”. Potwierdza to właściwy kierunek interwencji środków UE, które były udostępniane przede wszystkim na rozwój tego czynnika rozwoju.
Źródło:
Nierówności Społeczne a Wzrost Gospodarczy; 2023, 75; 29-46
1898-5084
2658-0780
Pojawia się w:
Nierówności Społeczne a Wzrost Gospodarczy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Contact interactions between soil and a corrugated metal sheet in soil-shell structures under construction
Autorzy:
Machelski, Czesław
Powiązania:
https://bibliotekanauki.pl/articles/2073757.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
soil-steel structure
corrugated metal sheet
construction phase
strain gauge
geodetic measurement
Opis:
During the construction of soil-shell objects, large deformations of the shell, which is made of corrugated metal sheet, occur. This enables geodetic techniques to be used when monitoring such objects. On this basis, displacements of selected points of the shell are determined, and it is then possible to obtain bending moments, as shown in this paper. Based on measurements using strain gauges in the circumferential band of the shell, internal forces in steel are estimated. The algorithm given in the paper enables the impact of soil on the shell in the examined objects to be analysed. The proposed method of analysing forces in the contact layer becomes especially useful when the static conditions of the model of a shell, which is considered as a bar submerged unilaterally in the soil medium, are met. The paper indicates the possibility of using both measuring techniques. Calculations include a smaller share of axial forces on the contact impact during the laying phase of the backfill. The paper provides examples of the analysis of built shells and record-breaking objects, with an assessment of the effectiveness of the proposed algorithm. Good mapping of contact forces, which were calculated on the basis of bending moments, was indicated even when there was not a dense grid of measuring points. An important advantage of the algorithm involves reduction of the circumferential band that is separated from the soil-shell system to the bar, which is an element resulting from the division of the structure into subsystems.
Źródło:
Studia Geotechnica et Mechanica; 2022, 44, 1; 1--12
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Displacements of shell in soil-steel bridge subjected to moving load: determination using strain gauge measurements and numerical simulation
Autorzy:
Machelski, Czesław
Sobótka, Maciej
Grosel, Szczepan
Powiązania:
https://bibliotekanauki.pl/articles/2073756.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
soil-steel structure
moving load
strain gauge
Opis:
This paper analyses displacements of a shell in a soil-steel bridge subjected to quasi-static moving loads. The considerations relate to a large span structure located in Ostróda, Poland. In particular, shell displacements during a loading cycle consisting of consecutive passages of a pair of trucks over the bridge are investigated. The results of a full-scale test, that is, the readings from a system of strain gauges arranged along the shell circumferential section, are the basis for determination of shell displacements. The proposed algorithm makes it possible to calculate any component of the displacement using just a simple model of the shell in the form of a linear elastic curvilinear beam. The approach uses real measurements, and thus, it yields results of displacements reflecting the actual mechanical behaviour of the entire composite structure including not only the shell, but also the backfill, the pavement, etc. The calculated state of displacement sets the basis for calibration of the numerical model. Finite element (FE) analyses include staged construction, that is, backfilling the shell by placing successive soil layers, as well as the loading test with the vehicles moving over the bridge. It is demonstrated that the ballasting of the shell during backfilling contributes to the improvement of the simulated behaviour of the object at the stage of operation, that is, when subjected to moving truck load. Thus, the calibration of the FE model is successfully carried out using the results of strain gauge measurements.
Źródło:
Studia Geotechnica et Mechanica; 2022, 44, 1; 26--37
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electrofusion tensometry applied to the research of engineering structures
Autorzy:
Zamiar, Zenon
Surowiecki, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/2056539.pdf
Data publikacji:
2022-06-07
Wydawca:
Międzynarodowa Wyższa Szkoła Logistyki i Transportu
Tematy:
reinforced soil
retaining structure
splinter wedge
electrofusion strain gauge
Opis:
The subject of the article concerns the problem of estimating the location of a slip line in a massif with a vertical retaining wall made of reinforced soil, in which the limit state of active pressure was induced. The task is solved experimentally, on the basis of measured unit strains in the reinforcement inserts, with the use of electrofusion strain gauges. The inserts are located in horizontal layers. The slip curve is formed by the points where the maximum normal stresses occur in the reinforcement inserts. This curve cuts off the fragment wedge that is being sought from the plane of the retaining wall. The slip line divides the area of the massif into two zones: active (splinter wedge) and passive, in which the reinforcement inserts are anchored. The test stand is presented, the technique of measuring the deformation of the reinforcement and the method of estimating the location of the slip surface are discussed.
Źródło:
Logistics and Transport; 2022, 53-54, 1-2; 119-132
1734-2015
Pojawia się w:
Logistics and Transport
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Powstanie i funkcjonowanie Bogatyńskiej Kolei Dojazdowej w konsekwencji zmiany granic po II wojnie światowej. 133 Dawid Keller, Polskie kolejowe porozumienia graniczne w okresie PRL na wybranych przykładach
Autorzy:
Jakuboszczak, Paweł
Powiązania:
https://bibliotekanauki.pl/articles/2184997.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Wrocławski. Wydział Nauk Historycznych i Pedagogicznych. Instytut Historyczny
Tematy:
narrow-gauge railway
local railway
Bogatynia
Turoszów
Opis:
The article presents the functioning of Bogatynia Local Railway, which came into being through the division of Saxon Narrow-Gauge Railway (Sächsische Schmalspurbahn Zittau – Hermsdorf) as a result of border changes following World War II. The new territorial division caused creation of three separate railway lines within the borders of Czechoslovakia, German Democratic Republic (until 1949 – Soviet Occupation Zone of Germany) and Poland. The cross-border rail traffic between Germany and Czechoslovakia did not use these lines anymore. Moreover, the section of the line within the Polish territory was deprived of stations having a connection to a normal-gauge railway. In new geopolitical circumstances, the Bogatynia Local Railway was not launched until 1951, after a connection with the narrow-gauge railway line for coal transport to Turoszów had been established – a normal-gauge link to Turoszów had also been built. However, the functioning of the Bogatynia Local Railway was marred with various problems, which led to its closure in 1961. The Bogatynia–Turoszów section was then replaced with a standard-gauge link.
Źródło:
Śląski Kwartalnik Historyczny Sobótka; 2022, 77, 3; 133-159
0037-7511
2658-2082
Pojawia się w:
Śląski Kwartalnik Historyczny Sobótka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of methods of monitoring structure deformations based on tests of a column-plate slab
Porównanie metod monitorowania odkształceń konstrukcji na podstawie badań stropu słupowo-płytowego
Autorzy:
Nykiel, Damian
Powiązania:
https://bibliotekanauki.pl/articles/1955928.pdf
Data publikacji:
2021
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
mesurement
deformations
column-plate slab
electrofusion strain gauge
fiber optic gauge
pomiary
odkształcenia
strop słupowo-płytowy
tensometr elektrooporowy
tensometr światłowodowy
Opis:
This work includes a comparison of the methods of monitoring the deformations of a structure on the example of a flat plate slab test. Classic ESG (electrofusion strain gauges) and modern DFOS (distributed fiber optic sensors) were compared. During the research, both types of sensors were used on some of the reinforcing bars. The study aims to indicate the differences between the compared monitoring methods, both in terms of the obtained results and their utility values.
Źródło:
Budownictwo i Architektura; 2021, 20, 4; 5-16
1899-0665
Pojawia się w:
Budownictwo i Architektura
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dydaktyczny system pomiarowy do współpracy z czujnikami tensometrycznymi
Didactic measuremt system for cooperation with strain gauge sensors
Autorzy:
Furmankiewicz, Leszek
Sawicki, Marcin
Powiązania:
https://bibliotekanauki.pl/articles/2031396.pdf
Data publikacji:
2021
Wydawca:
Politechnika Gdańska. Wydział Elektrotechniki i Automatyki
Tematy:
wzmacniacz tensometryczny
pomiary mostkowe
pomiary tensometryczne
strain gauges amplifier
bridge measurement system
strain gauge measurement
Opis:
W artykule przedstawiono projekt i budowę systemu pomiarowego przystosowanego do współpracy ze stanowiskiem dydaktycznym, znajdującym się na wyposażeniu Laboratorium Przetworników i Systemów Pomiarowych Instytutu Metrologii, Elektroniki i Informatyki Uniwersytetu Zielonogórskiego. Zaproponowany system pozwala na badania tensometrów i układów mostkowych. Składa się on ze stanowiska dydaktycznego, rozbudowanego wzmacniacza tensometrycznego oraz aplikacji na komputer PC, która pozwala na sterowanie tym wzmacniaczem poprzez interfejs szeregowy. Artykuł zawiera: koncepcję systemu pomiarowego, strukturę blokową wzmacniacza, rozwiązania techniczne wybranych bloków funkcjonalnych, wyniki badań torów pomiarowych oraz właściwości aplikacji przeznaczonej do współpracy z urządzeniem.
The paper presents an extended structure and construction of a measurement system for cooperation with the training stand located in the laboratory of the Institute of Electrical Metrology, Electronics and Computer Science, of the University of Zielona Góra. The measurement system allows testing of strain gauges and bridge systems. The system consists of three independent components: the training stand, an advanced strain gauges amplifier and a server. The training stand allows to determine the sensors characteristics as a function of a metal bar deflection and allows to study the influence of the temperature on the work of the strain gauges. The advanced strain gauges amplifier is a multifunctional device, capable of measuring differential voltage, resistance, current and temperature. The precision operational amplifiers and reference voltage sources used during the construction of the instrumentation amplifier allowed to obtain the accuracy of the measurement at a level close to the average class of measuring equipment. The modular structure of the system enables the construction of various measurement systems, where it is necessary to measure voltage, current, resistance or temperature.
Źródło:
Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej; 2021, 73; 17-22
1425-5766
2353-1290
Pojawia się w:
Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental determination of forces through measurements of strains in the side frame of the bogie
Autorzy:
Boronenko, Yuriy
Rahimov, Rustam
Powiązania:
https://bibliotekanauki.pl/articles/2098166.pdf
Data publikacji:
2021
Wydawca:
Politechnika Śląska. Wydawnictwo Politechniki Śląskiej
Tematy:
running dynamic tests
dynamic addition coefficient
frame force
side frame
load
strain gauge
connection scheme
prowadzenie badań dynamicznych
współczynnik dodatku dynamicznego
siła ramy
rama boczna
obciążenie
tensometr
schemat połączeń
Opis:
This paper investigates the influence of longitudinal and lateral forces on the accuracy of measurements of vertical forces for three-piece bogies. Theoretical studies of the loading of the bogie side frame have been carried out using the finite element method under the action of forces from a wheelset. The places of installation of strain gauges and the method of processing the received signals are determined. A method has been developed for measuring the vertical and lateral forces, which makes it possible to increase the accuracy of measurements of the vertical force, with the help of which the safety of movement is assessed during running dynamic tests and to ensure the simultaneous measurement of vertical and lateral (frame) forces transmitted to the boogie side frame, which will allow to reduce the number of strain gauges for measuring the considered forces during tests.
Źródło:
Transport Problems; 2021, 16, 3; 199--211
1896-0596
2300-861X
Pojawia się w:
Transport Problems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Insight Into Vibration Sources in Turbines
Autorzy:
Moneta, Grzegorz
Jachimowicz, Jerzy
Pietrzakowski, Marek
Doligalski, Adam
Szwedowicz, Jarosław
Powiązania:
https://bibliotekanauki.pl/articles/2105187.pdf
Data publikacji:
2021
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
vibrations
blade
gas turbine
turbine engine
strain gauge
tip timing
Additive Manufacturing
Opis:
Despite of nearly 100 years of turbine engine development and design, blade vibrations remain a great engineering challenge. The rotating turbine blades’ vibrations lead to cyclic oscillations, which result in alternating stress and strain in harsh environments of high temperature and pressure. In modern aeroengines, high hot flow velocities might generate erosion and corrosion pitting on the metal surfaces, that leverage remarkably mean stresses. The combination of both mean and alternating stresses can lead to unexpected engine failures, especially under resonance conditions. Then, alternating stress amplitudes can exceed the safety endurance limit, what accelerates the high cyclic fatigue leading quickly to catastrophic failure of the blade. Concerning the existing state-of-the-art and new market demands, this paper revises forced vibrations with respect to excitation mechanisms related to three design levels: (i) a component like the blade design, (ii) turbine stage design consisting of vanes and blades and (iii) a system design of a combustor and turbine. This work reviews the best practices for preventing the crotating turbine and compressor blades from High Cyclic Fatigue in the design process. Finally, an engine commissioning is briefly weighed up all the pros and cons to the experimental validations and needed measuring equipment.
Źródło:
Fatigue of Aircraft Structures; 2021, 13; 40--53
2081-7738
2300-7591
Pojawia się w:
Fatigue of Aircraft Structures
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reconstruction of small components using photogrammetry: a quantitative analysis of the depth of field influence using a miniature step gauge
Autorzy:
Guerra, Maria Grazia
Galantucci, Luigi Maria
Lavecchia, Fulvio
De Chiffre, Leonardo
Powiązania:
https://bibliotekanauki.pl/articles/1849141.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
metrology of small parts
uncertainty
photogrammetry
depth of field
miniature step gauge
flatness
dimensional accuracy
Opis:
In this work, authors investigated the effect of the Depth of Field (DoF) reduction, arising when the acquisition of small objects is carried out with a photogrammetry-based system using a Digital Single Lens Reflex (DSLR) camera and the structure from motion (SfM) algorithm. This kind of measuring instrument is very promising for industrial metrology according to the paradigms of the fourth industrial revolution. However, when increasing the magnification level, necessary for the reconstruction of sub-millimetric features, there is a corresponding decrease of the DoF, leading to possible effects on the reconstruction accuracy. Thus, the effect of the DoF reduction was analysed through the reconstruction of a well-known artefact: the step gauge. The analysis was conducted considering the theory behind the DoF concept, the analysis of the 2D images, input of photogrammetric reconstruction and, finally, the results in terms of dimensional verification of the reconstructed step gauge.
Źródło:
Metrology and Measurement Systems; 2021, 28, 2; 323-342
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studying the Sensitivity of Satellite Altimetry, Tide Gauge and GNSS Observations to Changes in Vertical Displacements
Autorzy:
Pająk, Katarzyna
Kowalczyk, Kamil
Kaminskis, Jānis
Idzikowska, Magdalena
Powiązania:
https://bibliotekanauki.pl/articles/1838004.pdf
Data publikacji:
2021
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
GNSS
satellite altimetry
sea level
tide gauge
vertical crustal movements
Opis:
Tide gauge observations provide sea level relative to the Earth’s crust, while satellite altimetry measures sea level variations relative to the centre of the Earth’s mass. Local vertical land motion can be a significant contribution to the measured sea level change. Satellite altimetry was traditionally used to study the open ocean, but this technology is now being used over inland seas too. The difference of both observations can be used to estimate vertical crustal movement velocities along the sea coast. In this paper, vertical crustal movement velocities were investigated at tide gauge sites along the Adriatic Sea coast by analyzing differences between Tide Gauge (TG) and Satellite Altimetry (SA) observations. Furthermore, the estimated vertical motion rates were compared with those from nearby GNSS measurements. The study determines the practical relationships between these vertical crustal movements and those determined from unrelated data acquired from the neighbouring GNSS stations. The results show general consistence with the present geodynamics in the Adriatic Sea coastal zone.
Źródło:
Geomatics and Environmental Engineering; 2021, 15, 4; 45-58
1898-1135
Pojawia się w:
Geomatics and Environmental Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Historyczne uwarunkowania tworzenia systemów kolejowych na świecie (6). Różnice techniczne w kształtowaniu sieci
Historical legacy in the form and performance of railway networks (6). Technical differences in shaping the Network
Autorzy:
Wesołowski, Jacek
Powiązania:
https://bibliotekanauki.pl/articles/252462.pdf
Data publikacji:
2020
Wydawca:
Instytut Naukowo-Wydawniczy TTS
Tematy:
interoperacyjność
rozstaw szyn
skrajnia
systemy elektryfikacyjne
interoperability
track gauge
loading gauge
electrification systems
Opis:
Fakt, że na wielkich obszarach Europy przyjęto „stephensonowski” rozstaw szyn jest zapewne pochodną wpływu inżynierii brytyjskiej. Nie przeszkodziła ona przyjęciu innych szerokości toru w niektórych krajach, co może wskazywać na decydującą rolę polityki rządów na wczesnym etapie budowy kolei. Z drugiej strony, ujednolicenie szerokości torów w Ameryce Północnej było najczęściej długotrwałym procesem, choć wyjątkowo stało się też epizodem jednego przedsięwzięcia, stanowiącym majstersztyk organizacyjny. Swoboda doboru rozstawu szyn na terytoriach zależnych od Brytanii, wraz z praktyką budowy wąskotorowych “kolei ekonomicznych”, złożyły się poza Europą na liczne przypadki nieciągłości sieci kolejowych, które wciąż czekają na rozstrzygnięcie. Ujednolicenie skrajni, chociaż nie tak niezbędne, jak w przypadku torów, jest również procesem podyktowanym chęcią bardziej ekonomicznego wykorzystania potencjału przewozowego na całości sieci kontynentalnej. W zakresie systemów elektryfikacji, „interoperacyjność” uzyskuje się przede wszystkim za pomocą taboru wielosystemowego. Historia jednak zna również przypadki przebudowy infrastruktury – największy z nich miał zapewne miejsce we Włoszech.
In spite of the key role Great Britain played in the early age of railways as the exporter of technology and products, universal unification of technical parameters of rail networks was not achieved. This article contains a short history of multiplicity of track gauges, loading gauges and electrification systems. It does not deal with many other features, like coupling types or train control and signaling systems. British influence undoubtedly settled the adoption of an awkward Stephenson’s track gauge on vast areas of Europe. It did not prevent, however, the use of other gauges in some countries which proves the governments had a decisive say in railway construction. On the contrary, track gauge unification in North America was a long process with a remarkable episode of one concerted action, itself a masterpiece of logistics and organization. The ‘inventiveness’ in track gauge in British dependencies, combined with an attempt to build narrow-track ‘economic railways’, contributed to the abundance of break-of-gauge spots outside Europe remaining yet to overcome. Unification of loading gauges, though not a necessity as absolute as in case of tracks, is also a process borne by attempt to use railway transport capacity more evenly across continents. While tackling the differences in electrification is mostly a story of running multi-system rolling stock, some major infrastructure rebuilding was also involved (the biggest occurred in Italy).
Źródło:
TTS Technika Transportu Szynowego; 2020, 7-8; 12-16
1232-3829
2543-5728
Pojawia się w:
TTS Technika Transportu Szynowego
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modular Test Stand for Fatigue Testing of Aeronautical Structures - Verification of Assumptions
Autorzy:
Leski, Andrzej
Wronicz, Wojciech
Kowalczyk, Piotr
Szmidt, Michał
Klewicki, Robert
Włodarczyk, Karol
Uliński, Grzegorz
Powiązania:
https://bibliotekanauki.pl/articles/2105142.pdf
Data publikacji:
2020
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
fatigue
test
airframe
veryfication
strain gauge
DIC
Opis:
The Modular Test Stand was developed and manufactured to decrease the cost of fatigue testing and reduce the time of its completion as well as to enable testing specimens under more complex load conditions. The stand consists of three connected sections, similar to a wing box, all being loaded in the same way. Thanks to that, several specimens can be tested simultaneously. This configuration requires that stress and strain distribution should be reasonably uniform, as assumed in the design stage. The structure can be loaded with bending or torsion. A whole section, selected structural node or a specimen mounted in the structure as well as a repair or a sensor can be a test object. Two stands, one for bending and one for torsion were prepared. This paper presents the verification of the assumed strain and stress distributions on the skin panels. The measurements were performed with the use of Digital Image Correlation (DIC) as well as strain gauges. DIC measurements were performed on one skin panel of the central section. Five strain gauge rosettes were installed on both panels of the one section. In addition, one rosette was applied to one skin panel in each of two other sections. Measurements were performed on the stand for torsion as well as on the stand for bending. The results of DIC analysis and strain gauge measurement during torsion show uniform shearing strain distributions on the panels. During bending, on the tensioned side, the strains obtained indicate quite uniform strain distributions. On the compressed side, local buckling of the skin panels results in high strain gradients. Strain levels obtained with the use of a DIC analysis and strain gauge measurements were similar. Moreover, horizontal displacements of markers in the spar axis during bending was determined based on a series of photographic. The deflection line obtained in this way has a shape similar to arc, which is characteristic of the constant bending moment. The stand was tested with torsional and bending loads in order to verify the design assumptions. The results of strain distributions on the skin panels with the use of DIC and strain gauges as well as the deflection line of the spar axis indicate that the Modular Test Stand performs as assumed and can be used for tests.
Źródło:
Fatigue of Aircraft Structures; 2020, 12; 78--91
2081-7738
2300-7591
Pojawia się w:
Fatigue of Aircraft Structures
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 158

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