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    Wyświetlanie 1-4 z 4
    Tytuł:
    Mathematical modeling of the stress-strain state of the annular preventer seal using the theory of reinforced shells
    Autorzy:
    Grydzhuk, Jaroslav
    Chudyk, Ihor
    Slabyi, Orest
    Mosora, Yurii
    Kovbaniuk, Mariana
    Krynke, Marek
    Powiązania:
    https://bibliotekanauki.pl/articles/26073542.pdf
    Data publikacji:
    2022
    Wydawca:
    Stowarzyszenie Menedżerów Jakości i Produkcji
    Tematy:
    pierścieniowy zawór odcinający
    wzmocniona powłoka
    kombinowana uszczelka gumowo-metalowa
    stan naprężenia-odkształcenia
    annular preventer
    reinforced shell
    combined rubber-metal seal
    stress-strain conditions
    Opis:
    Management of wells in the process of their construction is one of the important factors in ensuring the safety of the technological process. Blowout equipment, which includes annular preventers, is used to control the wells. This applies to the construction of oil and gas wells, or wells that provide degassing of coal seams to reduce their gas-dynamic activity. For the purpose of safe and long-term operation of annular preventers on the basis of the theory of thick-walled combined reinforced shells and the carried-out analytical research, the mathematical model for research of a stress-strain condition of a seal of an annular preventer has been offered. Taking into consideration the real design, the seal of the annular preventer is modeled by a rubber shell, reinforced in the circular direction by rubber frames, and in the longitudinal direction by metal stringers. The mathematical model provides for determining the stiffness, internal force factors and stresses in the longitudinal and transverse sections of the combined rubber-metal seal, considering the peculiarities of its operation. At the same time, the model includes the conditions of interaction of the rubber base of the seal with a pipe, as well as the action of sealing pressure under operating conditions. The use of the proposed mathematical model reduces the costs of experimental research and will contribute to ensuring the reliability of simulation modeling results. The advantage of the method is the determination of calculated loads at different points of the combined seal under the existing state of dangerous zones and the influence of operating conditions. In the meantime, prerequisites have been created for expanding the possibilities of simulation modeling and designing structural elements of annular preventers with increased operational characteristics. The practical value of the obtained results is determined by the possibility of using them to ensure the performance of the rubber-metal seal both at the stage of its design and during the operation.
    Źródło:
    Production Engineering Archives; 2022, 28, 4; 375--380
    2353-5156
    2353-7779
    Pojawia się w:
    Production Engineering Archives
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Sub-level stoping in an underground limestone quarry: an analysis of the state of stress in an evolutionary scenario
    Wybieranie podpoziomowe wapienia w podziemnych kamieniołomach: analiza stanów naprężeń w scenariuszu rozwojowym
    Autorzy:
    Cardu, M.
    Dipietromaria, S.
    Oreste, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/220245.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    eksploatacja podziemna
    wybieranie podpoziomowe
    stan naprężeń i odkształceń
    współczynnik bezpieczeństwa
    modelowanie numeryczne
    metoda wybierania
    underground exploitation
    sub-level stoping
    stress-strain conditions
    safety factor
    numerical modelling
    mining method
    Opis:
    The aim of this study was to evaluate the state of stress of a „voids-pillar“ structure excavated by means of the sub-level stoping method in an underground limestone quarry near Bergamo (Italy). Both the current structure of the quarry (i.e. the rooms exploited till now) and a possible future scenario were analysed using the (FDM) FLAC 2D code. The quarry has been in operation since 1927; at present, exploitation is carried out underground via the sub-level stoping method. Exploitation involves two levels, with 5 rooms on the upper level and 9 rooms on the lower level. After analysing data obtained from laboratory and in situ tests carried out on rock samples and natural discontinuities, the geomechanical properties of the medium, knowledge of which is essential in order to establish the parameters that must be included in the numerical model, were evaluated. The implementation of three numerical models made it possible to study both the present conditions of quarry exploitation and the evolution of the exploited rooms, as well as a possible expansion involving a third level of rooms. Using the results obtained regarding the stress-strain present in the pillars, a potential change in room geometry was proposed aimed at reducing the stress state inside the pillars, decreasing plasticity and increasing overall quarry safety.
    Celem pracy było zbadanie stanów naprężeń w strukturach składających się z filarów i pustek po wybieraniu wapienia w podziemnym kamieniołomie w pobliżu Bergamo (Włochy), metodą wybierania podpoziomowego. Zarówno obecna struktury kamieniołomu (komory powstałe po dotychczasowym wydobyciu) oraz możliwe scenariusze na przyszłość przeanalizowano przy użyciu kodu (FDM) FLAC 2D. Eksploatacja kamieniołomu trwa od 1972, w chwili obecnej wydobycie odbywa się pod ziemią, metodą wybierania podpoziomowego, na dwóch poziomach wybierania: 5 komór na poziomie wyższym i 9 komór – na niższym. Po analizie danych uzyskanych drogą testów laboratoryjnych oraz badania w terenie próbek skalnych i stref nieciągłości, określono właściwości geomechaniczne ośrodka niezbędne do obliczenia parametrów do modelu numerycznego. Implementacja trzech modeli numerycznych umożliwiła analizę zarówno obecnych warunków eksploatacji kamieniołomu, procesów zachodzących w wyeksploatowanych komorach, jak i projektowanie ewentualnego rozszerzenia wydobycia, w tym powstanie trzeciego poziomu. Wykorzystując otrzymane zależności naprężeń i odkształceń, zaproponowano zmiany w geometrii komór mające na celu obniżenie poziomu naprężeń w filarach, zmniejszenie ich podatności i ogólne podniesienie stanu bezpieczeństwa w kamieniołomie.
    Źródło:
    Archives of Mining Sciences; 2016, 61, 1; 199-216
    0860-7001
    Pojawia się w:
    Archives of Mining Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Comparison of solutions for microseismic focal mechanism estimation
    Autorzy:
    Wandycz, P.
    Święch, E.
    Pasternacki, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/184552.pdf
    Data publikacji:
    2016
    Wydawca:
    Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
    Tematy:
    stress condition
    strain conditions
    subsurface
    Opis:
    One of the major advantages of microseismic data, recorded during hydraulic fracturing of prospective shale intervals is ability to use both P and S wave in the analysis, not only to determine epicentral locations of events but also to describe source itself. The information about the mechanisms of located microseismic events allows better understanding of in situ stress and strain conditions and the local subsurface geomechanical properties and forces (Kamei et al. 2015). As Duncan stated in his work, a proper characterization of the observed events mechanisms is the key to understand radiation pattern of the signals in the investigated area (Duncan & Eisner 2010). Moreover, an understanding of the nature of the rock failure supports reservoir simulation models and stimulated reservoir volume estimates (Kratz & Thorton 2016). Proper assessment of event strike, dip and rake provides the geometry of the fracture plane assuming double couple focal mechanism, while full moment tensor inversion provides information about shear and tensile nature of the calculated mechanisms. The common method to obtain reliable focal mechanisms of observed microseismic events is decomposing of the full moment tensor. Seismic moment tensor is powerful tool which provides a general mathematical solution of sources that can be used to distinguish between various types of microseismic events. The method comes to reliably estimation of the six independent components of a full moment tensor by lestsquares inversion (Eaton & Forouhideh 2010). The motivation for this analysis was to determine microseismic focal mechanisms based on P – wave peak amplitude, P and S – waves peak amplitudes and S – wave peak amplitude only to estimate the differences and uncertainties between these three different solutions. Furthermore authors decided to check how the mechanisms changes with different geometries of downhole monitoring array. In this study only synthetic data computed in MiVu GeoTomo software using raytracing method and simple layered velocity model were used. The mentioned velocity model was constructed based on well logs data delivered by PGNiG from measurements done in Northern Poland where active exploration of shale gas takes place. In this analysis authors focused only on double couple (DC) and compensated linear vector dipole (CLVD) mechanisms which are two most common types of microseismic focal mechanisms occur during hydraulic fracturing of shale deposits. Performed analysis proved that the best and most consistent results with the lowest uncertainties reflected in the condition number parameter can be obtained by using both P and S peak amplitudes.
    Źródło:
    Geology, Geophysics and Environment; 2016, 42, 1; 137-138
    2299-8004
    2353-0790
    Pojawia się w:
    Geology, Geophysics and Environment
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Analytical solution of mixed boundary value problems using the displacement potential approach for the case of plane stress and plane strain conditions
    Autorzy:
    Deb Nath, S. K.
    Powiązania:
    https://bibliotekanauki.pl/articles/266247.pdf
    Data publikacji:
    2017
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    rozwiązanie analityczne
    naprężenie płaskie
    odkształcenie
    wartość graniczna
    analytical solution
    displacement potential approach
    plane stress and plane strain conditions
    mixed boundary value problems
    Opis:
    Two elastic plate problems made of duralumin are solved analytically using the displacement potential approach for the case of plane strain and plane stress conditions. Firstly, a one end fixed plate is considered in which the rest of the edges are stiffened and a uniform load is applied to the opposite end of the fixed end. Secondly, a plate is considered in which all of the edges are stiffened and a uniform tension is applied at its both ends. Solutions to both of the problems are presented for the case of plane stress and plane strain conditions. The effects of plane stress and plane strain conditions on the solutions are explained. In the case of stiffening of the edges of the plate, the shape of the plate does not change abruptly, which is clearly observed in both of the cases. For the plane strain condition, the plates become stiffer in the loading direction as compared to the plane stress condition. For the plane strain condition, there is a significant variation of the normal stress component, σzz at different sections of the plate. The graphical results, clearly identify the critical regions of the plate for the case of the plane stress and plane strain condition.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2017, 22, 2; 269-291
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
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