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    Wyświetlanie 1-11 z 11
    Tytuł:
    Functional behavior of pseudoelastic niti alloy under variable amplitude loading
    Autorzy:
    Iasnii, Volodymyr
    Yasniy, Petro
    Lapusta, Yuri
    Yasniy, Oleg
    Dyvdyk, Oleksandr
    Powiązania:
    https://bibliotekanauki.pl/articles/1837926.pdf
    Data publikacji:
    2020
    Wydawca:
    Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
    Tematy:
    pseudoelastic alloy
    NiTi alloy
    functional fatigue
    variable amplitude loading
    strain range
    residual strain
    dissipation energy
    Opis:
    Cyclic loading of superelastic NiTi shape memory alloy (SMA) causes forward and reverse austenite–martensіte transfor-mations, and also increases the volume of stabilized martensite. This appears in the change of stress-strain curve form, the decrease of dissipation energy, and increase of residual strain, that is, named transformation ratcheting. In real structures, the SMA components in most cases are under the action of variable amplitude loading. Therefore, it is obvious that the loading history will influence the functional fatigue. In the present work, the effect of stress ratio on the functional properties of superelastic NiTi shape memory alloy under variable amplitude loading sequence with two blocks was investigated. The studies were carried out under the uniaxial tension of cy-lindrical specimens under load-full unload and load-part unload. The change of residual strain, strain range, dissipation, and cumulative dissipation energy density of NiTi alloy related to load sequences are discussed. Under both stress ratios, the residual strain in NiTi alloy is increased depending on the number of loading cycles on the high loading block that is similar to the tests at constant stress or strain amplitude. An unusual effect of NiTi alloy residual strain reduction with the number cycles is found at a lower block loading. There was revealed the effect of residual strain reduction of NiTi alloy on the number of loading cycles on the lower amplitude block. The amount of decrement of the residual strain during a low loading block is approximately equal to the reversible part of the residual strain due to the stabilized martensite. The decrease of the residual strain during the low loading block is approximately equal to the reversible part of residual strain due to the stabilized martensite. A good correlation of the effective Young’s modulus for both load blocks with residual strain, which is a measure of the volume of irreversible martensite, is observed.
    Źródło:
    Acta Mechanica et Automatica; 2020, 14, 3; 154-160
    1898-4088
    2300-5319
    Pojawia się w:
    Acta Mechanica et Automatica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Deformation properties of sedimentary rocks in the process of underground coal gasification
    Autorzy:
    Bukowska, M.
    Sygała, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/92007.pdf
    Data publikacji:
    2015
    Wydawca:
    Główny Instytut Górnictwa
    Tematy:
    high temperature
    underground coal gasification
    residual strain
    Poisson's ratio
    wysoka temperatura
    podziemna gazyfikacja węgla
    odkształcenie trwałe
    współczynnik Poissona
    Opis:
    The article presents results of research into changes in deformation properties of rocks, under influence of temperature, during the process of underground coal gasification. Samples of carboniferous sedimentary rocks (claystones and sandstones), collected in different areas of Upper Silesian Coal Basin (GZW), were heated at the temperature of between 100 and 1000-1200°C, and then subjected to uniaxial compression tests to obtain a full stress-strain curves of the samples and determine values of residual strain and Poisson's ratio. To compare the obtained values of deformation parameters of rocks, tested in dry-air state and after heating in a given range of temperature, normalised values of residual strain and Poisson's ratio were determined. Based on them, coefficient of influence of temperature on tested deformation parameters was determined. The obtained values of the coefficient can be applied in mining practice to forecast deformability of gangue during underground coal gasification, when in the direct surrounding of a georeactor there are claystones or sandstones. The obtained results were analysed based on classification of uniaxial compression strength of GZW gangue, which formed the basis for dividing claystones and sandstones into very low, low, medium and high uniaxial compression strength rocks. Based on the conducted tests it was concluded that the influence of uniaxial compression strength on the value of residual strain, unlike the influence of grain size of sandstones, is unambiguous within the range of changes in the parameter. Among claystones changes in the value of Poisson's ratio depending on their initial strength were observed. Sandstones of different grain size either increased or decreased the value of Poisson's ratio in comparison with the value determined at room temperature in dry-air conditions.
    Źródło:
    Journal of Sustainable Mining; 2015, 14, 3; 144-156
    2300-1364
    2300-3960
    Pojawia się w:
    Journal of Sustainable Mining
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Local Phenomena During Riveting Process
    Autorzy:
    Kaniowski, J.
    Wronicz, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/97899.pdf
    Data publikacji:
    2013
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
    Tematy:
    riveting
    fatigue
    strain gauge
    FE model
    residual stress
    airframes
    Opis:
    The paper presents experimental and numerical study of the local phenomena during the riveting process. It is commonly accepted that technological factors of the riveting process has a strong influence on the fatigue life of riveted joints. The authors analysed the papers concerned the experimental researches of the riveting force influence on fatigue life. The magnitude of the life increase caused by the riveting force increase suggests the authors that this is not only the result of beneficial stress system but the change of the joint formation mechanism has taken place. This was an inspiration to undertake more detailed researches of the riveting process. The strain progress during the riveting process has been experimentally investigated for four types of aluminium rivets used in airframes. Measurements confirm very high strains near the driven head. For some types of rivets the reversal strain signal has been recorded. Several FE model has been use to investigate the riveting process. The axisymmetric and solid models were used. The agreement of experimental and numerical results in some cases were good, in other cases the numerical models demand further development. In any calculations, the reversal strain effect has not been obtained, This suggest that it is result of the phenomenon which has not been taken into account in numerical modelling. The working hypothesis has been assumed that during the riveting process adhesive joints (called cold welding) were formed and destroyed during the process, what was the reason of the observed reversal strain signal. The authors are going to continue this investigation.
    Źródło:
    Fatigue of Aircraft Structures; 2013, 5; 66-78
    2081-7738
    2300-7591
    Pojawia się w:
    Fatigue of Aircraft Structures
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The theoretical and experimental analyses of the influence of single draft on properties of rope wires
    Analiza teoretyczo-doświadczalna wpływu wielkości gniotu pojedyńczego na własności drutów liniarskich
    Autorzy:
    Suliga, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/355832.pdf
    Data publikacji:
    2012
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    rope wire
    single draft
    mechanical properties
    fatigue strength
    residual stresses
    roughness
    redundant strain
    effective strain
    temperature
    Opis:
    In the paper the influence of the value of a single draft on the properties of rope wires has been assessed. The drawing process of φ 5.5 mm wire rod to the final wire of φ 2.18 mm was conducted in 6, 11 and 17 drafts, by means of a block drawing machine with the drawing speed of 1.6 m/s. For the wires drawn with the medium single draft: 10.4%, 15.5% and 26.5% the investigation of mechanical-technological properties has been done, in which yield strength, tensile strength, elongation, contraction, number of twists and number of bands were determined. In order to explain the effect of value of a single draft on properties of rope wires, the fatigue strength, roughness and residual stresses of drawn wires have been also determined. In addition, the numerical analysis of the drawing process on the base of Drawing 2D in which distribution of redundant strain, effective strain, longitudinal residual stresses and temperature of drawn wires has been shown. The theoretical-experimental analysis of drawing of rope wires have enabled the evaluation of optimal value of single drafts by which relatively the most advantageous and useful properties of wires can be used. The investigation has shown, that in manufacturing of rope wires small single draft in 10% range should be applied. It allowed to obtain products of good plasticity properties, low deformation inhomogeneity and residual stresses, high bending and fatigue strength. The obtained data investigation can be applied while designing the production process of high carbon steel wires.
    W pracy określono wpływ wielkości gniotów pojedynczych na własności drutów liniarskich. Proces ciągnienia walcówki o średnicy 5.5 mm na średnice 2.18 mm zrealizowano w 6, 11 i 17 ciągach na ciągnące jednobębnowej z prędkością ciągnienia 1.6 m/s Dla drutów ciągnionych ze średnim gniotem pojedynczym: 10.4%, 16.5% i 26.5% przeprowadzono badania własności mechaniczno-technologicznych, w których określono umowna granice plastyczności, wytrzymałość na rozciąganie, wydłużenie równomierne i całkowite, przewężenie, liczba skręceń i liczbę zgięć. Dla pełniejszej oceny wpływu wielkości gniotu pojedynczego na własności drutów liniarskich przeprowadzono także badania wytrzymałości zmęczeniowej, chropowatości powierzchni i naprężeń własnych. Dodatkowo w pracy w oparciu o program Drawing 2d przeprowadzono analizę numeryczna procesu ciągnienia, w której określono odkształcenia postaciowe, intensywność odkształcenia, naprężenia własne i temperaturę ciągnionych drutów. Przeprowadzona analiza teoretyczno-doświadczalna procesu ciągnienia drutów ze stali wysokowęglowej umożliwiła określenie optymalnych wartości gniotów pojedynczych przy których uzyskuje się względnie najlepsze własności użytkowe drutów. Stwierdzono, ze przy wytwarzaniu drutów linairskich należy stosować małe wielkości gniotów pojedynczych, rzędu 10%. Pozwala to uzyskać wyroby o dobrych własnościach plastycznych, małej niejednorodności odkształcenia, małych naprężeniach własnych, wysokiej wytrzymałości na zginanie oraz dużej wytrzymałości zmęczeniowej. Uzyskane wyniki badan mogą być wykorzystane przy projektowaniu procesu wytwarzania drutów ze stali wysokowęglowych.
    Źródło:
    Archives of Metallurgy and Materials; 2012, 57, 4; 1021-1030
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Behaviour of cement concrete at high temperature
    Autorzy:
    Hager, I.
    Powiązania:
    https://bibliotekanauki.pl/articles/201988.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    concrete
    high temperature
    fire damage
    thermal strain
    transient thermal strain
    hot tested mechanical properties
    residual properties
    Opis:
    The paper presents the impact of high temperature on cement concrete. The presented data have been selected both from the author’s most recent research and the published literature in order to provide a brief outline of the subject. The effect of a high temperature on concrete covers changes taking place in cement paste, aggregates, as well as the interaction of these two constituents, that result in changes of mechanical and physical characteristics of concrete. This paper presents the effects of a high temperature on selected physical properties of concrete, including colour change, thermal strain, thermal strains under load, and transient thermal strains. In addition, changes to mechanical properties are discussed: stress-strain relationship, compressive strength, and modulus of elasticity. Moreover, the phenomenon of explosive spalling and the main factors that affect its extent are analysed in light of the most recent research.
    Źródło:
    Bulletin of the Polish Academy of Sciences. Technical Sciences; 2013, 61, 1; 145-154
    0239-7528
    Pojawia się w:
    Bulletin of the Polish Academy of Sciences. Technical Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    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:
    Diagnostics and optimisation of crane track durability in metallurgical plant
    Autorzy:
    Kuľka, J.
    Faltinová, E.
    Kopas, M.
    Mantič, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/329642.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
    Tematy:
    diagnostics
    bridge crane
    crane track
    strain gauge measurement
    residual durability
    diagnostyka
    czujnik tensometryczny
    pomiar
    suwnica pomostowa
    trwałość resztkowa
    Opis:
    This paper deals with questions concerning technical diagnostics and optimisation of fatigue durability for the crane track beams installed in a metallurgical plant. The fatigue durability is determined using a strain gauge measurement in order to calculate the relevant residual durability of the crane track beams. Consequently, there are proposed suitable measures that are necessary with regard to the next operation of the given crane track, which is supporting a bridge crane.
    Źródło:
    Diagnostyka; 2016, 17, 3; 41-46
    1641-6414
    2449-5220
    Pojawia się w:
    Diagnostyka
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The influence of thermomechanical coupling on the behaviour of athick-walled metallic tube subjected to internal pressure
    Autorzy:
    Śloderbach, Z.
    Powiązania:
    https://bibliotekanauki.pl/articles/264368.pdf
    Data publikacji:
    2018
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    grubościenna rura
    naprężenia rzeczywiste
    naprężenia szczątkowe
    odkształcenia
    ciśnienie
    thick-walled tube
    thermomechanical coupling
    actual and residual stresses
    strain
    pressure
    Opis:
    In this study, the influence of thermomechanical coupling effect - the effect of thermal expansion due to dissipation of the energy of plastic deformation, with and without taking into account the stored energy of plastic deformation (SEPD) for the distribution of stresses, strains, temperature, the applied pressure and the residual stresses is examined. The residual stresses remain in a thick-walled tube (a cylindrical thick-walled tank) after removing the internal pressure in the process of purely elastic unloading. The analysis is made on the example of an analitycal solution for a thick-walled tube subjected to a quasistatically increasing internal pressure for the case of adiabatic processes (without heat flow). Since the loading with internal pressure is quasi-static (monotonic), then neglecting the process of heat flow can lead to some different results in calculated stresses, deformations, temperature, internal pressure and residual stresses. The calculations for isothermal type of processes of deformations (without heat or ideal cooling) are also performed for the estimation of these differences. The results calculated for the process with heat flow should be intermediate between the values obtained for isothermal and adiabatic processes.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2018, 23, 3; 751-766
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The influence of the multipass drawing process in clasical and hydrodynamic dies on residual stresses of high carbon steel wires
    Wpływ wielostopniowego procesu ciągnienia w ciągadłach klasycznych i hydrodynamicznych na naprężenia własne w drutach ze stali wysokowęglowej
    Autorzy:
    Suliga, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/352653.pdf
    Data publikacji:
    2011
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    naprężenie
    stal wysokowęglowa
    ciągadła klasyczne
    ciągadła hydrodynamiczne
    temperatura
    residual stresses
    high carbon steel
    multipass wire drawing
    classical and hydrodynamic dies
    temperature
    redundant strain
    Opis:
    n the paper the influence of the multipass drawing process on residual stresses of high carbon steel wires has been assessed. The drawing process of φ5.5 mm wires to the final wire of φ1.6 mm was conducted in 11 passes, in industrial conditions, by means of a modern Koch multi-die drawing machine. The drawing speed in the last passes was 10 m/s. The experimental measure of residual stresses in wires drawn in classical and hydrodynamic dies by Sachs-Linicus method has been done. On the basis of numerical analyses of the wire drawing process, the distributions of longitudinal residual stresses on the cross section of wires, temperatures and redundant strain have been determined. The investigations have shown the essential influence of the multipass drawing process in hydrodynamic dies on residual stresses of high carbon steel wires. In the case of the wires drawn with hydrodynamic dies, in comparison to the wires drawn in classical dies, the 30% decrease of longitudinal residual stresses have been noted. It has been shown that the decrease of residual stresses in wires drawn in hydrodynamic dies is connected with a lower redundant strain by 14.7%. In addition, the application of hydrodynamic dies in the multipass drawing process leads to significant decreasing of temperature of the wire surface (in the last pass above 500 °C). Undoubtedly, the large increase of temperature in the sub-layer of wires drawn in classical die caused the rise of internal stresses related to the thermal expansion of steel. In consequence, it caused the increase of residual stresses.
    W pracy określono wpływ wielostopniowego procesu ciągnienia na naprężenia własne w drutach ze stali wysokowęglowej. Proces ciągnienia drutów o średnicy 5,5 mm na średnicę końcową 1,60 mm zrealizowano w 11 ciągach, w warunkach przemysłowych, na nowoczesnej ciągarce wielostopniowej Kocha. Prędkość ciągnienia na ostatnim ciągu wynosiła 10 m/s. Naprężenia własne w drutach po procesie ciągnienia w ciągadłach klasycznych i hydrodynamicznych wyznaczono w oparciu o badania doświadczalne wykorzystując metodę Sachsa-Linicusa. Natomiast w oparciu o analizę teoretyczną procesu ciągnienia określono rozkłady wzdłużnych naprężeń własnych na przekroju drutów, temperaturę, odkształcenia postaciowe i intensywność odkształcenia. Wykazano, że stosowanie w procesie wielostopniowego ciągnienia drutów wysokowęglowych ciągadeł hydrodynamicznych przyczynią się do znaczącego spadku wzdłużnych naprężeń własnych. Dla drutów ciągnionych w ciągadłach hydrodynamicznych, w stosunku do drutów ciągnionych w ciągadłach klasycznych, odnotowano spadek o około 30% wzdłużnych naprężeń własnych I rodzaju. Spadek naprężeń własnych w drutach ciągnionych w ciągadłach hydrodynamicznych należy wiązać z występowaniem dla tego wariantu mniejszych o 14,7% odkształceń postaciowych. Ponadto zastosowanie ciągadeł hydrodynamicznych w procesie wielostopniowego ciągnienia prowadzi do zasadniczego spadku temperatury drutu na jego powierzchni (w ostatnim ciągu o ponad 500 C). Znaczący wzrost temperatury w warstwie przypowierzchniowej drutów ciągnionych klasycznie przyczynił się do powstania naprężeń wewnętrznych związanych z rozszerzalnoącią cieplna\ą stali, co w konsekwencji spowodowało wzrost naprężeń własnych.
    Źródło:
    Archives of Metallurgy and Materials; 2011, 56, 4; 939-944
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Finite element analysis of thermal stress in Cu2O coating synthesized on Cu substrate
    Autorzy:
    Shorinov, O.
    Powiązania:
    https://bibliotekanauki.pl/articles/24200560.pdf
    Data publikacji:
    2022
    Wydawca:
    Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
    Tematy:
    stress-strain state
    residual stress
    oxide layers
    thermo-mechanical modelling
    coefficient of thermal expansion
    stan naprężenie-odkształcenie
    naprężenie szczątkowe
    warstwy tlenkowe
    modelowanie termomechaniczne
    współczynnik rozszerzalności cieplnej
    Opis:
    Purpose: The paper aims to find the magnitude and nature of thermal residual stresses that occur during cooling of a copper sample with a thermally synthesized oxide layer of Cu2O. Design/methodology/approach: Thermo-mechanical analysis was performed by the finite element method using Ansys Software. The results of thermal analysis were used to study the resulting stress-strain state of the thin film/coating system after cooling. Findings: Based on the modeling results, the paper determined the most stress-strain areas of the sample with a coating, which are the free edges of the interfaces between the copper substrate and the Cu2O oxide layer. Research limitations/implications: The main limitations of the study are the use of certain simplifications in the condition setup, for instance, uniform cooling of the thin film/coating system, homogeneity and isotropy of substrate and thin film materials, invariance of their properties with temperature changes, etc. Practical implications: The results obtained can be used to control the stress-strain state of the thin film/coating system and prevent deformations and destruction of thin-film structures during their production and operation of products with them. Originality/value: The study of new promising methods for the formation of oxide nanostructures, for instance in a plasma environment, requires a sufficient theoretical basis in addressing the origin and development of stresses.
    Źródło:
    Archives of Materials Science and Engineering; 2022, 115, 2; 58--65
    1897-2764
    Pojawia się w:
    Archives of Materials Science and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
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