Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "Miedzińska, D." wg kryterium: Autor

  Lista filtrów
Wyrównaj
Wyświetlanie 1-15 z 28
Tytuł:
Numerical study on closed cell foam structure damage mechanisms
Autorzy:
Miedzińska, D.
Powiązania:
https://bibliotekanauki.pl/articles/246654.pdf
Data publikacji:
2012
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
closed cell foam
finite element method
X-ray tomography
damage
Opis:
Metallic foams are currently being looked at as a new material for automobiles. The main goal of the use of metallic foams in vehicles is to increase sound dampening, reduce the weight of the automobile, and increase energy absorption in case of crashes, or in military applications, to combat the concussive force of IEDs. The metallic foams that are being looked at currently, are aluminum and its alloys due to their low density (0.4-0.9 g/cm3). In addition these foams have a high stiffness, are fire resistant, do not give off toxic fumes, are fully recyclable, have high energy absorbance, have low thermal conductivity, have low magnetic permeability, and are efficient at sound dampening, especially in comparison to light weight hollow parts. In addition, partial addition of metallic foams in hollow parts of the car will decrease weakness points usually associated with car crashes and noisy vibrations. These foams are cheap to cast by using powder metallurgy (as compared to casting of other hollow parts). The aim of the research was to describe and to assess the main mechanisms that appear in the foam structure during the compression. The development process of the finite element model of the closed cell foam microstructure is presented in the paper. The model geometry was based on the real structure research, which was carried out with the use of computed tomography. The model was built with the use of a unique computer code created to transform the scan point cloud into FE raster model based on solid 8-node elements. The experimental and numerical compression test results were compared and showed good compatibility. The stress distributions were studied to describe the main mechanisms in the structure.
Źródło:
Journal of KONES; 2012, 19, 2; 321-327
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical investigations on vibrating motion with inertial load of vibratory pile hammer stiffly coupled with excavator
Autorzy:
Osiński, J.
Miedzińska, D.
Powiązania:
https://bibliotekanauki.pl/articles/247648.pdf
Data publikacji:
2014
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
elastomer
vibrations
simulation
resonance
numerical analysis
Opis:
A vibratory pile hammer (VPH) is a mechanical device used to drive steel piles as well as tube piles into soil to provide foundation support for buildings or other structures. In order to increase the stability and the efficiency of the VPH work in the over-resonance frequency, a new VPH construction was developed in the Military University of Technology. The new VPH contains a system of counter-rotating eccentric weights, powered by hydraulic motors, and designed in such a way that horizontal vibrations cancel out, while vertical vibrations are transmitted into the pile. This system is suspended in the static parts by the adaptive variable stiffness pillows based on a smart material, magnetorheological elastomer (MRE), which rheological and mechanical properties can be reversibly and rapidly controlled by an external magnetic field. The work presented in the paper is a part of the modified VPH construction design process. It concerns the development of the numerical model of the VPH and soil interaction that will describe resonance conditions, resonance frequencies with consideration of soil susceptibility, coupling phenomenon and elastomer changeable stiffness. On the base of developed theoretical equations, the frequency of VPH piling will be regulated to assure the over-resonance work.
Źródło:
Journal of KONES; 2014, 21, 1; 189-195
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical analysis of an open cell foam structure with the use of models based on 2D finite elements
Autorzy:
Szymczyk, W.
Miedzińska, D.
Powiązania:
https://bibliotekanauki.pl/articles/242137.pdf
Data publikacji:
2009
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
FEM modelling
open cell foam structure
effective properties
Opis:
The paper deals with the numerical analysis of foam materials. Open cell foam is investigated. Numerical simulations allow calculating modes of destruction and assessing effective properties of the model structures. Metal as well as polyurethane foams show out interesting properties. They are light, have good acoustic and/or magnetic isolation, have ability to absorb energy of vibration and hits. They are used for sandwich panels, hit absorber s (i.e. as elements of buffer constructions in rail vehicles),fillers of construction parts, bodies of vehicles (i.e. floating combat vehicles), dividing walls on vessels and others. Specially prepared open cell foams show out auxetic properties and shape memory effect. Such materials are very good for seats in aircrafts which may protect pilots and passengers during crashes and restrict heavy backbone injuries. Foams are used for filtering purposes. Foams themselves or in combination with different types of fillers (i.e. elastomers) or ceramic reinforcement may be used for hit energy absorbing panels for military purposes (protection against explosion shock wave and splinters). Presented work is a part of a series of numerical experiments which aim is to investigate the influence of geometry parameters onto effective properties of the foam. Different types of geometries are used for numerical experiments. All the models of single foam cell are based on Kelvin grain geometry. Numerical compression tests performed with the use of models based on 2D finite elements provide studying the process of the structure failure. Effective characteristics of investigated foams show out that such materials would be useful for energy absorbing purposes.
Źródło:
Journal of KONES; 2009, 16, 2; 441-448
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Blast loading on aluminum foam microstructure
Autorzy:
Miedzińska, D.
Panowicz, R.
Powiązania:
https://bibliotekanauki.pl/articles/244041.pdf
Data publikacji:
2010
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
microstructure
aluminium foam
strain rate effect
Opis:
One of the possible options as a material for protective layers is aluminum foams which become also very popular due to their lightweight and excellent plastic energy absorbing properties. Such characteristics have been appreciated by the automotive industry with continued research to further understand foam properties. Compressed foaming materials exhibit extensive plastic response, while the initial elastic region is limited in tension by a tensile brittle-failure stress. Aluminum foams have become also an attractive material as blast protective layers due to their desirable compressive properties. With different material engineering techniques (as, for example double-layer foam cladding) they can be customized to achieve the most desirable properties. Energy absorption capacity of foams microstructures under blast load was analytically confirmed based on a rigid-perfectly plastic-locking foam model Initial research indicates that energy absorbed by the cladding is much larger than that under quasi-static conditions due to strain rate effect. In this paper a numerical model of a closed cell aluminum foam idealistic microstructure was presented. The quasi static compression tests were carried out with the use of LS Dyna computer code. Then the sample was numerically loaded with the blast wavefrom detonation of explosives and its behavior was analyzed. The results ofboth analyses were compared.
Źródło:
Journal of KONES; 2010, 17, 3; 287-292
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Methods of CO2 acquisition and costs reduction in shale rocks fracturing technology
Autorzy:
Miedzińska, D.
Niezgoda, T.
Powiązania:
https://bibliotekanauki.pl/articles/299042.pdf
Data publikacji:
2016
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
fracturing
shale gas
carbon dioxide
economics
Opis:
The innovative method of shale gas recovery with the use of subcritical CO2 is currently developed within the project titled “Development of guidelines for design of innovative technology of shale gas recovery with the use of liquid CO2 on the base of numerical and experimental research – DIOX4SHELL ”, supported by the National Centre for Research and Development (NCBR). The project is carried out by Polish company PGNiG and by academics from WAT, AGH and PW (Military University of Technology, AGH University of Science and Technology, and Warsaw University of Technology). Finding the best business model, in which costs of CO2 production or acquisition are negligible is one of the most important factors influencing the economical effectiveness of the technology. The main part of known CO2 acquisition methods is based on fuel purchase and its combustion, what is very expensive process. It results with the high CO2 price, when purchasing from producer, about 300 zl/ton. This price is quite high, considering current low prices of natural gas. In the paper basic aspects of CO2 acquisition from CO2 producers, exhaust gases treatment plants or plasma gasification methods will be presented.
Źródło:
AGH Drilling, Oil, Gas; 2016, 33, 1; 11-22
2299-4157
2300-7052
Pojawia się w:
AGH Drilling, Oil, Gas
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical analysis of an open cell foam structure with the use of models based on solid finite elements
Autorzy:
Szymczyk, W.
Miedzińska, D.
Powiązania:
https://bibliotekanauki.pl/articles/245581.pdf
Data publikacji:
2009
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
FEM modelling
open cell foam structure
effective properties
Opis:
The paper deals with the numerical analysis of foam materials. Open cell foam is investigated. Numerical simulations allow calculating modes of destruction and assessing effective properties of the model structures. Metal as well as polyurethane foams show out interesting properties. They are light, have good acoustic and/or magnetic isolation, have ability to absorb energy of vibration and hits. They are used for sandwich panels, hit absorber s (i.e. as elements of buffer constructions in rail vehicles), fillers of construction parts, bodies of vehicles (i. e. floating combat vehicles), dividing walls on vessels and others. Specially prepared open cell foams show out auxetic properties and shape memory effect. Such materials are very good for seats in aircrafts which may protect pilots and passengers during crashes and restrict heavy backbone injuries. Foams are used for filtering purposes. Foams themselves or in combination with different types of fillers (i.e. elastomers) or ceramic reinforcement may be used for hit energy absorbing panels for military purposes (protection against explosion shock wave and splinters). Presented work is apart of a series of numerical experiments which aim is to investigate the influence of geometry parameters onto effective properties of the foam. Different types of geometries are used for numerical experiments. All the models of single foam cell are based on Kelvin grain geometry. Numerical compression tests performed with the use of models based on solid finite elements provide studying the process of the structure failure. Effective characteristics of investigated foams show out that such materials would be useful for energy absorbing purposes.
Źródło:
Journal of KONES; 2009, 16, 3; 409-414
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Aluminium foam testing for impact energy absorption aims
Autorzy:
Niezgoda, T.
Miedzińska, D.
Powiązania:
https://bibliotekanauki.pl/articles/245628.pdf
Data publikacji:
2009
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
aluminium foam
microstructure modelling
open cell foam
closed cell foam
Opis:
Aluminium foams are a new group of materials used for impact energy absorbing elements. They are light (typically 10-25% of the density of the metal they are made of) and stiff, and are frequently proposed as a light weight structural material. That is why they often are applied in automotive and transport industry solutions, for example as parts of bumpers. The methods of numerical modelling for open and closed cell aluminium foams are presented in the paper as well as closed and open cellfoam microstructure model. The numerical models of foam ideal microstructures created with shell finite elements are shown. The models were developed on the basis of Kefain tetrakaidecahedrons - structures consisting of six squares and eight hexagons. In the case of closed cell foams, the polyhedron with full walls was adopted. In the case of open cell foams the circle wholes were removed from polyhedron surfaces. Then the numerical analysis of a created models compressive test was carried out with the usage of LS Dyna computer code. The nonlinear procedures were applied. The results were analyzed in the scope of energy absorbing properties of aluminium foams.
Źródło:
Journal of KONES; 2009, 16, 3; 283-289
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical modelling of the foamed materials structures with the usage of the 2D and beam elements
Autorzy:
Miedzińska, D.
Szymczyk, W.
Powiązania:
https://bibliotekanauki.pl/articles/245977.pdf
Data publikacji:
2010
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
foamed aluminium
microstructure
FE modelling
Kelvin structure
Opis:
The possible options as materials for protective layers are aluminium foams which become also very popular due to their lightweight and excellent plastic energy absorbing properties. Such characteristics have been appreciated by the automotive industry with continued research to further understandfoam properties. Compressed foaming materials exhibit extensive plastic response, while the initial elastic region is limited in tension by a tensile brittle-failure stress. Aluminium foams have become an attractive material as blast protective layers due to their desirable compressive properties. With different material engineering techniques (as, for example double-layer foam cladding) they can be customized to achieve the most desirable properties. Energy absorption capacity of foams under blast load was analytically confirmed based on a rigid-perfectly plastic-locking foam model. Initial research indicates that energy absorbed by the cladding is much larger than that under quasi-static conditions due to shock wave effect. The methods of numerical modellingfor open and closed cell aluminium foams arepresented in the paper. The numerical models of foam ideal microstructures created with shell and together shell and beam finite elements are shown. The models were developed on the basis of Kelvin tetrakaidecahedrons - structures consisting of six sąuares and eight hexagons. In the case of open cell foams the circle wholes were removed from polyhedron surfaces. Then the numerical analysis o f a created models compressive test was carried out with the usage of MSC.Marc computer code. The nonlinear procedur es were applied. The results were analyzed in the scope of the assessing the behaviour of the open cell aluminium foam unit cell under the compressive load.
Źródło:
Journal of KONES; 2010, 17, 1; 267-272
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative study of hybrid foam microstructure models
Autorzy:
Szymczyk, W.
Miedzińska, D.
Powiązania:
https://bibliotekanauki.pl/articles/246261.pdf
Data publikacji:
2010
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
FEM modelling
foam structure
elastomer filament
geometry orientation
Opis:
Cellular solids are materials made out of solid strut or thin plate like structures bridged together. They occur in nature in the form of honeycombs, wood, bone, cork etc. These materials possess a unique combination of properties such as low thermal conductivitv, low density and high energy-absorption. Foams are a class of cellular solids, generally made by dispersing gas into a liquid material and then cooling it to solidify. They are categorized as open-cell and closed-cell foams. Depending on the solid materials that are made into foams, they are also categorized as polymeric foams, metallic foams, and ceramic foams. Due to developments in material science and manufacturing lechniques, advanced foams have found potential for use in automobile, aircraft, and space vehicle structures. In the paper the comparative study of the hybrid foam microstructures is presented. Hybrid foam is a new, still developed material that is built of the aluminum open cell foam matrix filled with other material (here: elastomer). The numerical models based on cubic geometry in different configurations are developed. The FE analysis of the compression test is curried out. The results are presented and analyzed due to the microstructure geometry influence on the material behaviour.
Źródło:
Journal of KONES; 2010, 17, 4; 505-511
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical calculations of RVE dimensions for two-phase material
Autorzy:
Miedzińska, D.
Niezgoda, T.
Powiązania:
https://bibliotekanauki.pl/articles/242298.pdf
Data publikacji:
2011
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
microstructure
two-phase material
metal-ceramic composite
RVE
Opis:
A representative volume element (RVE) is a statistical representation of typical material properties. It should contain enough information on the microstructure thereby be sufficiently smaller than the macroscopic structural dimensions. The paper deals with the numerical calculations of the dimensions of the RVE for a two-phase material microstructure. Two and three dimensional models are taken into consideration. The structure of the samples are developed on the base of randomization of elements belonging to one of the phases. The phases volume share is 50/50%. The following series of the models are analyzed: from 10 x 10 to 100 x 100 elements for 2D samples and from 10 x 10 x 10 to 100 x 100 x 100 elements for 3D samples. The element characteristic dimension is 10 jm. The elastic behavior of the base materials (magnesium and alumina) is taken into account. The quasi-static compression tests of the developed structures are carried out with the use of LS-DYNA computer code. The results are presented as the equivalent Young modulus values and compared to the calculations based on the rule of mixtures. The stabilization of the achieved results allows to assess the dimensions of the RVE for two-phase material with random distribution.
Źródło:
Journal of KONES; 2011, 18, 2; 303-310
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Failure analysis of chosen 3D numerical models of an open cell foam
Autorzy:
Szymczyk, W.
Miedzińska, D.
Powiązania:
https://bibliotekanauki.pl/articles/243845.pdf
Data publikacji:
2010
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
FEM modelling
open cell foam structure
Opis:
Metal and polyurethane foams exhibit interesting properties. They are light, have good acoustic and/or magnetic isolation as well as ability to absorb the vibration and impact energy. They are used for sandwich panels, impact absorbers (i.e. as elements of the buffer constructions in rail vehicles), fillers ofconstruction parts, bodies of vehicles (i.e. floating combat vehicles) and for dividing walls of vessels and others. Speciflcally made open cell foams demonstrate auxetic properties and the shape memory effect. Such materials are very good for seats in aircrafts which may protect pilots and passengers during crashes and limit heavy backbone injuries. Foams are used for filtering purposes. Foams or their in combination with different types of fillers (i.e. elastomers) or the ceramic reinforcement may be used in impact energy absorbing panels for military aim (protection against an explosion shock wave and splinters). In the paper aluminium open-cell foam structures were investigated for their energy absorption ability. For this purpose a series of numerical 3D models were applied. Geometry of the models was based on Kehin's polyhedrons. Tests of uniaxial compression were simulated with the use of LS-Dyna computer code. Complex contact phenomena were considered. Preliminary test were performed with the use of single foam cell models. Further simulations were conducted using 3x3x3 cell models. The results were analyzed as force/time characteristics.
Źródło:
Journal of KONES; 2010, 17, 1; 449-454
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
CO2 - CH4 sorption induced swelling of gas shales: An experimental study on the Silurian shales from the Baltic Basin, Poland
Autorzy:
Miedzińska, D.
Lutyński, M.
Powiązania:
https://bibliotekanauki.pl/articles/109897.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
shale rock
swelling
methane
carbon dioxide
sorption
Opis:
The main aim of the research presented in the paper was to study the phenomena of shale swelling induced by CH4 and CO2 sorption. In the study, a Silurian gas shale sample from the Baltic Basin in Poland was used. Samples represented typical characteristic features of polish shale gas formations with relatively low total organic carbon (0.8%) and high clay mineral content. The first part of the study was devoted to competitive adsorption of CO2 and CH4. The second part was devoted to observation of the sorption induced swelling phenomena, where sample linear strains were monitored with the use of strain gauges. Swelling tests were conducted up to the pressure of approximately 8 MPa with CO2, CH4 and helium as the baseline. Experimental results were compared with the Seidle and Huitt model where Langmuir constants where determined with volumetric sorption tests. Results of the study showed that matrix swelling in case of CO2 adsorption was greater than in the case of CH4 adsorption. The swelling value was directly proportional to adsorption and was about 5 to 10 times smaller than in the case of coal. Sorption of methane and carbon dioxide in the gas-bearing shale was about 10-times lower than in hard coals. The Seidle and Huitt model developed for coals was equally suitable to describe the processes of shale swelling.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 2; 415-427
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Laboratory hydraulic fracturing tests of rock samples with water, carbon dioxide, and slickwater
Szczelinowanie hydrauliczne próbek skalnych za pomocą wody, ditlenku węgla oraz „slickwater”
Autorzy:
Stanisławek, S.
Kędzierski, P.
Miedzińska, D.
Powiązania:
https://bibliotekanauki.pl/articles/230264.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
szczelinowanie hydrauliczne
stanowisko do szczelinowania
wytrzymałość na rozciąganie
skała
woda
ditlenek węgla
slickwater
hydraulic fracturing
fracturing test stand
tensile strength
rock
water
carbon dioxide
Opis:
Hydraulic fracturing of rocks boosts the production rate by increasing the fracture-face surface area through the use of a pressurized liquid. Complex stress distribution and magnitude are the main factors that hinder the use of information gathered from in situ hydraulic fracturing in other locations. Laboratory tests are a good method for precisely determining the characteristics of these processes. One of the most important parameters is breakdown pressure, defined as the wellbore pressure necessary to induce a hydraulic fracture. Therefore, the main purpose of this investigation is to verify fracture resistance of rock samples fractured with the assistance of the most popular industry fluids. The experiments were carried out using a stand designed specifically for laboratory hydraulic fracturing. Repeatable results with a relative error within the range of 6-11% prove that the experimental methodology was correct. Moreover, the obtained results show that fracturing pressure depends significantly on fluid type. In the case of a water test, the fracturing pressure was 7.1±0.4MPa. A similar result was achieved for slickwater, 7.5±0.7MPa; however, a much lower value (4.7±0.5MPa) was registered in the case of carbon dioxide.
Szczelinowanie hydrauliczne polega na niszczeniu skały za pomocą płynu pod wysokim ciśnieniem w celu zwiększenia powierzchni spękań, co poprawia wydajność produkcyjna. Rozkład naprężenia w górotworach i jego wielkoś jest zwykle relatywnie skomplikowana, a to utrudnia wykorzystanie informacji zgromadzonych w trakcie procesu szczelinowania w innej lokalizacji. Przy tym zwykle prace prowadzone są na dużym obszarze, a znaczna część instalacji znajduje się pod ziemią. W efekcie wiedza na temat warunków, w których przeprowadzono proces jest zwykle ograniczona. Dlatego próby laboratoryjne stanowią dobrą metodę weryfikacji parametrów procesu. Jedną z najistotniejszych wielkości jest ciśnienie szczelinowania niezbędne do wytworzenia spękań. Decyduje ono zarówno o parametrach instalacji szczelinującej jak i ma wpływ na aktywność sejsmiczną obszaru. W literaturze istnieją wzory pozwalające szacować wielkość ciśnienia szczelinującego, jednak nie uwzględniają one roli płynu szczelinującego. Najpopularniejszym medium szczelinującym stosowanym w przemyśle jest woda, często domieszkowana specjalnymi dodatkami redukującymi tarcie. W górotworach o szczególnie zwartej budowie stosuje się zwykle ditlenek węgla lub azot. Dotychczasowe badania nad wpływem płynu szczelinującego na wielkość ciśnienia miały ograniczony charakter. Ze względu na ten fakt praca podejmuje to zagadnienie.
Źródło:
Archives of Civil Engineering; 2017, 63, 3; 139-148
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
FEM analysis of proppant sticking in rock cracks
Analiza MES wciskania proppantu w pęknięcie skalne
Autorzy:
Kwietniewski, M.
Miedzińska, D.
Niezgoda, T.
Powiązania:
https://bibliotekanauki.pl/articles/231026.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
analiza MES
proppant
skała łupkowa
pęknięcie
szczelinowanie
kontakt
Newmark
FEM analysis
shale rock
crack
fracturing
contact
Opis:
The problem of effective gas extraction from Polish shale rocks is an interesting research subject for scientists. A properly selected proppant, which protects cracks from closing during the fracturing process, inestimably contributes to an increase of extraction. Grains of proppant are transported along with a fracturing medium to reach the deepest regions of the crack. The proper support of the crack provides an easy flow of gas, therefore it is important in terms of extraction efficiency. This paper shows the interactions of a proppant grain with the crack surface in shale rock. FEM analysis was conducted to observe the stress region, which is generated as a result of pressing the grain into the crack surface. A model of a sphere which was pressed into the rock model with constant velocity was applied. The received results of stress depend on material properties and a range of proppant grain pressing.
Terytorium Polski od kilku lat jest obiektem wzmożonych badań mających na celu opracowanie opłacalnej technologii wydobycia gazu z łupków. Polskie skały łupkowe różnią się pod względem fizycznym i chemicznym od tych występujących w Ameryce Północnej, są rozlokowane również na innej głębokości. Inna budowa skały stawia zatem nowe wyzwania dla wiertnictwa otworowego. Procesy szczelinowania zachodzą w nieco inny sposób, zatem konieczne jest opracowanie nowej technologii wydobycia. Jednym z ważniejszych aspektów tych badań jest dokładna analiza zachowania się skały obciążonej ciśnieniem szczelinowania. Do rozważenia jest tu mechanizm powstawania i propagacji pęknięcia oraz optymalny sposób podparcia szczeliny po zabiegu szczelinowania. Tę funkcję mają pełnić proppanty, które dostają się do złoża wraz z czynnikiem szczelinującym. Ziarenka, najczęściej ceramiczne o dużej twardości mają za zadanie zaklinować się w skale, aby utworzyć maksymalne rozwarcie szczeliny. Oczywiście, przy ogromnych naprężeniach wewnętrznych górotworu nastepuje wgniatanie ziaren w powierzchnię skały, co powoduje zmniejszenie przekroju poprzecznego szczeliny, a w skrajnych przypadkach może prowadzić do całkowitego zamknięcia szczeliny. Do analizy MES opracowano model geometryczny. Przyjęto, że model skały to czwarta część walca ze szczeliną w środkowej częćci o promieniu 1 mm. Wygenerowano model skały łupkowej o promieniu 8 mm oraz długości 10 mm. Analogicznie do modelu skały, przyjęto ziarenko proppantu jako 1/4 kuli. Dyskretyzację modelu przeprowadzono w oprogramowaniu LS – PrePost za pomocą elementów ośmiowęzłowych. Utworzony model składa się z 29554 elementów oraz 60696 węzłów.
Źródło:
Archives of Civil Engineering; 2018, 64, 2; 55-65
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical simulation of the beam made of magnetorheological elastomer bending in the magnetic field
Autorzy:
Miedzińska, D.
Sławiński, G.
Boczkowska, A.
Powiązania:
https://bibliotekanauki.pl/articles/245981.pdf
Data publikacji:
2010
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
magnetorheological elastomer
smart materials
numerical modelling
magnetic field influence
Opis:
Magnetorheological elastomers (MREs) belong to the group of so-called smart materials, which respond to an external stimulus by changing their viscoelastic properties. Magnetorheological (MR) material can be fluid, gel or solid like material, such as elastomer. The mechanical properties of the MR materials change when subjected to an external magnetic field. The MREs are interesting candidates for the active stiffness and vibration control of structural systems. In the paper the verification process of the applied FE modelling method is presented. The verification is based on the three point bending experiment. The results of that experiment were used to evaluation of the correction on numerical model and analysis. The model was based on the assumption that MRE behaves like an orthotropic material with the material properties o f MRE on the direction along the iron chains - and of a pure elastomer - on the other directions. Such an assumption can be made for the small deformations of a sample, what took place in the considered experiment. The FE modelling method was considered to be correct. On the base of the verified method a FE element model of the MRE beam bending was developed. Such MRE beams are used as "smart" switches that react under the changeable magnetic field.
Źródło:
Journal of KONES; 2010, 17, 1; 261-265
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 28

Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies