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Wyświetlanie 16-30 z 126
Tytuł:
Analysis of coal structure in the aspect of gas content
Autorzy:
Niezgoda, T.
Miedzińska, D.
Małek, E.
Powiązania:
https://bibliotekanauki.pl/articles/298731.pdf
Data publikacji:
2013
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
carbon dioxide
methane
porosity of coal
Opis:
The problem of methane existence in coal beds has been known for many years. It was and still is a danger to coalminers. The aim of the research presented in the paper is to show and assess the porosity structure (especially micro and nanoporosity) in accordance to the dimensions of carbon dioxide particle. The characteristic surface morphology of the sample and the disclosure of carbon porous structure was obtain using the scanning electron microscope (SEM). The presented study of the coal microstructure is a part of the coal demethanation method with the use of liquid CO2, that was proposed by Military University of Technology. Based on the results of laboratory tests may be noted that the analyzed coal has a granular structure. It is also visible that that the structure is stratified, and there is a lot of cracks and free space between grains, which can accumulated methane in coal structure. The nanoporosity of the coal grains was observed during SEM study. The sizes and shapes of pores are miscellaneous. However the dimension of 62-300 nm allow to draw a conclusion, that the nanopores can contain a few particles of CH4 (4 A), which can be released by the CO2 particle (2.54 A). Finally, on the base of presented research it can be concluded that the method of coal demethanation with the use of CO2 can be economically and ecologically effective, and can increase the miners safety.
Źródło:
AGH Drilling, Oil, Gas; 2013, 30, 1; 169-179
2299-4157
2300-7052
Pojawia się w:
AGH Drilling, Oil, Gas
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical and Experimental Comparison of Combined Multilayer Protective Panels
Autorzy:
Barnat, W.
Panowicz, R.
Niezgoda, T.
Powiązania:
https://bibliotekanauki.pl/articles/387055.pdf
Data publikacji:
2012
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
MES (metoda elementów skończonych)
fala uderzeniowa
interakcja struktury płynu
elastomery
panel energochłonny
FEM
blast wave
fluid structure interaction
elastomers
protective panel
Opis:
The paper presents numerical and experimental analysis of combined multilayer protective panels. The developed structures are prospective solutions for enhancing protection of military vehicles and crucial elements of pipelines especially in places like river crossings.
Źródło:
Acta Mechanica et Automatica; 2012, 6, 1; 148-153
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Walidacja pian niemetalicznych w złożonym stanie odkształcenia
The validations of constitutive models for non metallic foam under complex strain state
Autorzy:
Barnat, W.
Dziewulski, P.
Niezgoda, T.
Powiązania:
https://bibliotekanauki.pl/articles/387115.pdf
Data publikacji:
2009
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
walidacja
piana niemetaliczna
validations
non-metallic foam
Opis:
W niniejszym artykule przedstawiono wyniki badań energochłonności piany niemetalicznej obciążonej przemieszczeniem. Głównym celem pracy była walidacja modelu numerycznego spienionego polichlorku winylu wraz z oceną zdolności pochłaniania energii przez podstawowy element konstrukcji energochłonnej obciążonej dynamicznie. Elementy energochłonne przebadano w KMiIS. Badania przeprowadzono na maszynie wytrzymałościowej Instron. Obciążenie realizowano przez wymuszenie kinematyczne.
In the present article, the results of investigations of energy absorption foam structures weighted down were presented. The main objective of this study was the validations of constitutive models for non metallic foam. Investigations were conducted on Dynamic Testing System INSTRON in KMiIS. The load was applied by input function kinematic.
Źródło:
Acta Mechanica et Automatica; 2009, 3, 3; 5-8
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical study of the shape effect in the ceramic based ballistic panels
Autorzy:
Morka, A.
Jackowska, B.
Niezgoda, T.
Powiązania:
https://bibliotekanauki.pl/articles/245901.pdf
Data publikacji:
2009
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
computational mechanics
impact problem
armour perforation
ballistic resistance
ceramic armour
Opis:
The numerical investigations have been performed to determine the front surface shape effect in the cer based armour systems. Different shapes of ceramic elements were analyzed, including hemispheres and pyramids with respect to standard flat tiles. The influence of the impact point location was also under considerations. The Computer simulations were performed with the Element Free Galerkin Method (EFG) implemented in LS-D code. An impact of the 14.5xll8mm B32 armour piercing projectile on the A12O3 different shape elements backe 7017 aluminium alloy plate was analyzed. Full 3D models of the projectile and targets were developed with strain, rate and temperature dependent material constitutive relations. The models of the projectile, ceramic and aluminium alloy targets were validated with utilization of the experimental data found in literature. The obtained results confirm, the preliminary presumptions, that the shape of the front surface can significant role in the overall ballistic resistance of the panel. Particularly projectile-target initial contact area st to be important factor as showed by impact point location analysis. The conclusions presented in this paper can be applied to develop modern impact protection panels where the appropriate balance between the mass and protection level must be accomplished.
Źródło:
Journal of KONES; 2009, 16, 4; 539-548
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of human body exposed to blast wave derived from improvised explosive devices
Autorzy:
Sławiński, G.
Dziewulski, P.
Niezgoda, T.
Powiązania:
https://bibliotekanauki.pl/articles/246647.pdf
Data publikacji:
2015
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
vehicle safety
mine resistance
improvised explosive device
occupant safety
FEM analysis
Opis:
The analysis of contemporary military conflicts shows, that the most dangerous threat for soldiers are Improvised Explosive Devices (IEDs). Blast resistance of military vehicles and structures is broadly discussed in many articles. However, information about human body response to impact loading is hard to find and very general. Both experi-mental trials with dummies and numerical analyses are needed. To design and develop better protection system it is necessary to identify and measure the effects of blast wave impact on crew of military vehicle. This paper presents numerical simulation results of special armoured vehicle subjected to mine threat of 8 and 10 kg of TNT. Possible effects of mine explosion on human body are described. Review of modern-mine and IED countermeasure solutions is presented. The analysis is conducted using LS-DYNA explicit code. Only vehicle’s hull is considered with suspension and turret is modelled using mass. Gravity is taken into account. Numerical model of Hybrid-III dummy is used. Accelerations and forces in tibia, neck and spine were calculated. HIC-36 criterion was also evaluated Different types of possible seat configuration are examined. Results show convergence between explosive size and injury risk.
Źródło:
Journal of KONES; 2015, 22, 4; 287-294
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New method of carbon dioxide underground storage coupled with shale gas recovery
Autorzy:
Niezgoda, T.
Miedzińska, D.
Kędzierski, P.
Powiązania:
https://bibliotekanauki.pl/articles/246774.pdf
Data publikacji:
2012
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
shale gas
carbon dioxide
storage system
Opis:
Shale gas is natural gas produced from shale, a type of sedimentary rock. Shale gas has become an increasingly important source of natural gas in the United States over the past decade, and interest has spread to potential gas shales in Canada, Europe, Asia, and Australia. One analyst expects shale gas to supply as much as half the natural gas production in North America by 2020. As of 2010, Poland imports two-thirds of its natural gas from Russia. ConocoPhillips has announced plans to explore for shale gas in Poland, along with Lane energy. The recently made available US Department of Energy report revealed that the largest reserves of shale gas in Europe are in Poland. The authors of the report calculate that Poland has reserves of about 22.45 trillion cubic meters of shale gas, of which 5.30 trillion cubic meters is immediately available for extracting. The most common method of shale gas recovery is hydraulic fracturing - the propagation of fractures in a rock layer caused by the presence of a pressurized fluid. Hydraulic fractures form naturally, as in the case of veins or dikes, and is one means by which gas and petroleum from source rocks may migrate to reservoir rocks. This process is used to release petroleum, natural gas (including shale gas, tight gas and coal seam gas), or other substances for extraction, via a technique called induced hydraulic fracturing. The method is critically assessed by ecologists. The paper deals with new method of gas shale fracturing and gas recovery coupled with carbon dioxide storage. It allows to effectively mine the shale gas and to store carbon dioxide in shale rock. It must be noticed that CO2 pollution is a very important problem in Poland, because of European Union CO2 limits. Also the numerical calculation of carbon dioxide thermodynamical process of decompression process, which simulates the injection of the cold liquid gas into the shale formation (high temperature and pressure conditions) and its influence on shale rock fracturing will be presented.
Źródło:
Journal of KONES; 2012, 19, 3; 327-333
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of a light caterpillar vehicle loaded with blast wave from detonated IED
Autorzy:
Barnat, W.
Niezgoda, T.
Panowicz, R.
Powiązania:
https://bibliotekanauki.pl/articles/247638.pdf
Data publikacji:
2010
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
IED
vehicle shell
FE analysis
ground
Opis:
More and more impudent attacks on the military convoys in Afghanistan proved a huge danger of the improvised explosive devices - IED. Huger and more clever charges are a serious problem for vehicles protection. Additionally, hitherto defence standards and STANAG didn't predict such huge charges. Majority investigations were based on a 3 kg anti-tank mine. The article presents the results of numerical calculations for the elements of the combat vehicle supporting structure loaded with an impact generated by explosion of a huge explosive charge under the bottom of the vehicle with consideration of the wave reflected from the ground. Such an approach allows obtaining a good approximation of numerical simulations to real conditions of terroristic attacks. Additionally, the analysis of IED side influence on the vehicle shell was conducted. The explosive charge — IED — was simulated with the use of concentrated energy of properly selected (on the base of literature investigations) density and initial energy. During analyses of side explosive on the vehicle structure, the obstacle in the form of a building increasing the pressure impulse was taken into account. The paper presents the results of a numerical analysis in which Euler and Lagrange domains(describing a vehicle) were coupled. A perfect gas model was used to describe air parameters.. Additionally, the ground was described with a gas model. Every kind of material data were selected on the base of experimental investigations. A bilinear material model with a Cowper and Symonds strain rate model was used to describe a vehicle. Such an approach fully describes the phenomena occurring in the system.
Źródło:
Journal of KONES; 2010, 17, 4; 27-34
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pianki poliuretanowe - właściwości, zastosowania, recykling
Poliurethane foams - properties, applications, recycling
Autorzy:
Barnat, W.
Miedzińska, D.
Niezgoda, T.
Powiązania:
https://bibliotekanauki.pl/articles/357306.pdf
Data publikacji:
2011
Wydawca:
Politechnika Śląska
Tematy:
pianka poliuretanowa
tworzywa sztuczne
recykling
pouliurethane foam
polymers
recycling
Opis:
Pianka poliuretanowa jest tworzywem sztucznym składającym się z komórek litego poliuretanu, który otacza pęcherzyki gazu. Materiał ten może być sztywny lub podatny na odkształcenia, ale zawsze charakteryzuje się niską gęstością. Pianki najczęściej są produkowane w formie dużych bloków, które ucina się do pożądanych kształtów. Po zakończeniu okresu użytkowania poliuretany mogą być odzyskiwane w celu ponownego użycia lub poddawane recyklingowi chemicznemu. W artykule przedstawione zostały wybrane problemy związane z badaniem, zastosowaniem i w dalszej kolejności recyklingiem pian polimerowych.
Polyurethane foam refers to a number of different types of foam consisting of polymers made of molecular chains bound together by urethane links. It can be flexible or rigid, but has a low density. Flexible polyurethane is made in blocks and then cut to its desired shape. At the end of their service life, polyurethanes can be sent for reuse (for example, rebonding) or chemical recycling, or can be incinerated for energy recovery. The chosen problems connected with research, implementations and recycling of polyurethane foams were presented.
Źródło:
Archiwum Gospodarki Odpadami i Ochrony Środowiska; 2011, 13, 4; 13-17
1733-4381
Pojawia się w:
Archiwum Gospodarki Odpadami i Ochrony Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical model of bullet - barrel system
Model numeryczny układu lufa - pocisk
Autorzy:
Łazowski, J.
Małachowski, J.
Niezgoda, T.
Powiązania:
https://bibliotekanauki.pl/articles/241651.pdf
Data publikacji:
2007
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
lufa
pocisk
modelowanie numeryczne
barrel
bullet
numerical modelling
Opis:
Aktualnie, projektowanie uzbrojenia w dużej mierze opiera się na metodach analitycznych, które nie pozwalają na znaczną poprawę parametrów broni w zakresie odporności udarowej. Szczególnie istotna jest analiza dynamiki dla ruchu pocisku w lufie na stożku przejściowym i ustalenie optymalnych parametrów procesu. Na styku lufy i pocisku zachodzą bardzo złożone procesy termomechaniczne. Oddziaływanie to powoduje powstawanie na powierzchni styku ciał ciepła a w konsekwencji zmian właściwości mechanicznych. Dodatkowo charakter współpracy obu ciał obarczony jest często brakiem symetrii wynikającym między innymi z niedokładności wykonania elementów, nieodpowiednim osadzeniem pocisku w lufie oraz niejednorodnością materiałów. W skutek takiej złożoności zjawisk, której konsekwencją są np. zmienność współczynnika tarcia czy również drgania pocisku i lufy, ogólne analityczne wyznaczanie stanów naprężeń i stanów krytycznych w sposób ścisły jest niemożliwe. Jedyną skuteczną metodą może być w tym przypadku modelowanie numeryczne. W pracy przedstawiono próbę analizy stanu wytężenia powstającego podczas szybkozmiennych procesów w trakcie współpracy pocisku z lufą. Przedstawiono model numeryczny obiektów i zaprezentowano wyniki analizy w formie planów warstwicowych. Narzędziem zastosowanym do analizy był pakiet obliczeniowy LS-DYNA umożliwiający symulacje w zakresie nieliniowym z jawnym krokiem całkowania.
Currently the design process for armament equipment mostly employs very known and traditional analytical methods. But in many cases this kind of approach is not sufficient and effective, especially for gun parameters related with impact resistance. Very crucial for proper dynamic bullet movement in the barrel are geometric dimensions. In the contact areas between a bullet and a barrel appear some thermo-mechanical phenomena. Additionally, the cooperation process between these two components is encumbered because of the asymmetry caused by the inaccuracy of production process and the inhomogeneity of used materials. Finally, the mentioned reasons produce some unwanted effects like: bullet and barrel vibrations, problems with friction phenomena, etc. In such situations, the typical engineering approach in design process is unable to take into considerations all such local and very complex effects. Therefore, this paper presents is a trial of numerical methods application, which allow perform full analysis process of interaction between bullet and barrel. The models of these two bodies were developed using FE method. The numerical calculations were performed using LS-DYNA code. The main goal of the research was focused on contact problem. In the paper authors enclosed the initial results of the dynamic simulations.
Źródło:
Journal of KONES; 2007, 14, 1; 261-266
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preliminary concept of numerical modelling of combustion process for gunpowder using LS-DYNA code
Wstępna koncepcja numerycznego modelowania procesu spalania ładunku miotającego w systemie LS-DYNA
Autorzy:
Łazowski, J.
Małachowski, J.
Niezgoda, T.
Powiązania:
https://bibliotekanauki.pl/articles/241653.pdf
Data publikacji:
2007
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
lufa
pocisk
modelowanie numeryczne
balistyka wewnętrzna
spalanie
barrel
bullet
numerical modelling
internal ballistic
gunpowder burning
Opis:
In this paper the preliminary concept of numerical modelling of combustion process for gunpowder is presented. Such new computational methods like finite element analysis gave us opportunity to simulate such energetic and high-frequency process like pressure wave generation caused by chemical reaction. The main product of this process is a blast wave, which interacts at the first stage with surrounding (bullet and shell) and finally impel a bullet movement. In the considered case, the detonation product from gunpowder burning couple "produced" gas in Eulerian domain with the barrel-bullet system described in Lagrangian domain. In the performed analysis, the authors noticed some unwanted effects like asymmetry, which is probably related with the finite element mesh and computational errors. In the next conducting investigations some optimisation procedures related with a bullet movement in a barrel will be employed. The successful solution of such complicated problem like a proper simulation of the internal ballistic phenomena with taking into account all dynamic effects can significantly improve the problem of shooting accuracy. The initial calculations were performed using LS-Dyna code. At this stage the presented results have a qualitative character.
W pracy omówiono koncepcję symulacji komputerowej spalania materiału wybuchowego miotającego w układzie lufa- nabój. Takie nowoczesne sposoby obliczeniowe, oparte na metodzie elementów skończonych mogą dostarczyć możliwości symulacji szybkozmiennych procesów energetycznych wynikających ze zamiany energii chemicznej prochu na ciśnienie gazów prochowych i w konsekwencji w energię kinetyczną pocisku. Okazuje się, że zamodelowanie wytwarzania produktów spalania materiału miotającego jest zadaniem trudnym. W takich ekstremalnych warunkach charakter współpracy obu ciał może być obarczony np. brakiem symetrii wynikającym między innymi z asymetrycznego rozkładu ciśnienia produktów spalania materiałów miotających. W przypadku modelu dyskretnego koncepcja ta może zostać wykorzystana do rozwiązania problemu głównego balistyki wewnętrznej i optymalizacji konstrukcji układu lufa - nabój oraz symulacji właściwości dynamicznych rozpatrywanych obiektów w różnych fazach współpracy. Poniżej przedstawiono klasyczne sformowanie modelu dla broni lufowej oparte równań matematycznych i sposób zaimplementowania w modelu dyskretnym. Rozważania zilustrowano przykładowymi wynikami. Pracę realizowano przy wykorzystaniu licencjonowanego pakietu obliczeniowego LS-Dyna. Przedstawione wstępne wyniki mają charakter jakościowy.
Źródło:
Journal of KONES; 2007, 14, 1; 255-260
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical modeling of auxetics in structure strength
Autorzy:
Stanisławek, S.
Morka, A.
Niezgoda, T.
Powiązania:
https://bibliotekanauki.pl/articles/241667.pdf
Data publikacji:
2010
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
computational mechanics
auxetics
negative Poisson's ratio
material engineering
Opis:
The paper deals with computer simulations of mechanical behaviour of a no-void ideal auxetic isotropic material. Current literature offers wide range of models which resemble the manufactured or natural structures. However, it does not answer the question how a change into auxetic no-void state would affect the continuum effective mechanical properties. Auxetic with the Poisson ratio -0.3 has been compared through typical tests to a classic steel elastic material. Most of the engineering software cannot precede Poisson ratio helow zero. Therefore a unique technique was applied using equation of state to overcome this obstacle. All simulations have been done in elastic regime. For the tensile compression tests a 10 mm edge cube was modelled, the bending test used a 5x5x250 mm bar. The loading for initial tests was realized as a kinematic displacement of particular nodes. For bar bending a force was applied in the middle of the beam. The finite element method has been used with explicit time integration algorithm implemented in commercial software with one integration point brick elements. Specific properties have been observed for each test, for tensile test auxetic showed higher strength while for compression material was weaker. Logically the bending test showed no clear influence of negative Poisson to material strength. Further simulations as a shear or impact tests are planned.
Źródło:
Journal of KONES; 2010, 17, 4; 459-462
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental investigation of selected explosion parameters for numerical model
Autorzy:
Barnat, W.
Gieleta, R.
Niezgoda, T.
Powiązania:
https://bibliotekanauki.pl/articles/241757.pdf
Data publikacji:
2012
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
IED
improvised explosive device
numerical model
validation
Opis:
The aim of presented work is examination of blast wave, especially incident and reflected wave pressure. Due to many difficulties and complexity of phenomenon a complete study for different charges should be done. In presented paper two cylindrical TNT charges were used, weighting respectively 100 g and 200 g. Pressure wave was examined using original test stand designed and developed on Department of Mechanics and Applied Computer Science. A test steel test plate with 5 mm thickness was equipped with pressure gauge to measure reflected wave. Additionally, the plate was placed on four special electroresistance strain gauges...To measure force Vishay EA-06-120-060LZ strain gauges were used. For amplification of the dynamometers with strain gauges, MS1001 INFEL bridge was used. The system was used to validate the results from reflected wave pressure gauge. Shock wave pressures was measured using a special sensor model 137A21 amd M350B21 made by PCB Piezotronics At specific distance there was also incident wave pressure gauge. In order to fully examine the dynamic response of the plate an accelerometer was used. As a result, pressure versus time and acceleration versus time plots were obtained. The results will be used to validate numerical model of blast wave impact on a plate.
Źródło:
Journal of KONES; 2012, 19, 4; 9-13
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulations of motion of prototype railway wagon with rotatable loading floor carried out in MSC Adams software
Autorzy:
Niezgoda, T.
Krasoń, W.
Stankiewicz, M.
Powiązania:
https://bibliotekanauki.pl/articles/242161.pdf
Data publikacji:
2012
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
intermodal transport
railway wagon
simulation of motion
MSC ADAMS
Opis:
The railway wagon with a low flat rotatable loading floor was analysed in the paper. Such a structure can be used for transporting various types of vehicles such as tractors, trucks, trailers, semitrailers, cargo containers. The railway wagon allows quick and fast loading and unloading without any platform infrastructure or terminals. Only a hardened flat surface is required. Each railway wagon can be loaded-unloaded individually (no cranes needed). This construction has a wide range of application and is easy to operate. The model of a railway wagon consisted of standard carriages, undercarriages, and a rotatable loading floor was developed. The model was built of rigid solids. Between individual elements of the model, the appropriate joints and contact connections were created. The model was analysed using MSC Adams code, which allows performance of the 3D kinematic - dynamic analyses of the entire model. The analyses were carried out with use of the model of the loaded semitrailer. Passage of the railway wagon with a trailer on horizontal rails, which are the smallest standard arc with a radius 250m, was simulated at different speed. Reactions occurring in couplings of the rotatable loading floor, which are the main element of connection between the rotatable loading floor and motionless undercarriages part of the frame of the wagon, were tested. The maximum velocity at which the railway wagon can move was analysed as well. There was also examined the speed at which the wheels separate from the rails, what results in derailment of the whole wagon.
Źródło:
Journal of KONES; 2012, 19, 4; 495-502
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical analysis of a multi - component ballistic panel
Autorzy:
Stanisławek, S.
Morka, A.
Niezgoda, T.
Powiązania:
https://bibliotekanauki.pl/articles/243005.pdf
Data publikacji:
2012
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
computational mechanics
ballistic protection
composite armour
ceramics
Opis:
The paper presents a numerical study of a two layer composite panel impacted by an AP (Armour Piercing) 14.5x118mm B32 projectile. The panel consists of a number of pyramid ceramic components supported by an aluminium plate. The studied model is compared with a reference structure in which ceramic layer is in a form of a plate. The problem has been solved with the usage of modelling and simulation methods as well as a finite elements method implemented in LS-DYNA software. Space discretization for each option was built with three dimension elements guaranteeing satisfying accuracy of the calculations. For material behaviour simulation, specific models including the influence of the strain rate and temperature changes were considered. A steel projectile and aluminium plate material were described by Johnson-Cook model and a ceramic target by Johnson-Holmquist model. In the studied panels, the area surrounding back edges was supported by a rigid wall. The obtained results show interesting properties of the examined structures considering their ballistic resistance. All tests have given clear results about ballistic protection panel response under AP projectile impact. Panels consisting of sets of pyramids are slightly easier to penetrate. Despite this fact, a ceramic layer is much less susceptible to overall destruction what makes it more applicable for the armour usage. Furthermore, a little influence of the projectile impact point and consequently a part of the pyramid, which is first destroyed, is proved.
Źródło:
Journal of KONES; 2012, 19, 4; 585-588
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of armoured vehicles bottom shape on the pressure impulse
Autorzy:
Barnat, W.
Panowicz, R.
Niezgoda, T.
Powiązania:
https://bibliotekanauki.pl/articles/243701.pdf
Data publikacji:
2011
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
IED
improvised explosive device
mine resistance
armour
deflector
hull design
light armoured vehicle
Opis:
This paper presents the results of a numerical analysis of military vehicles hulls mine resistance. The research concerns armours loaded with blast wave from large IED charges in three cases. First is an explosion in Euler domain without any boundary conditions. Second consists of Euler domain with flat bottom and the ground. Third is simulated Euler domain with ground and deflector. Boundary conditions used both in second and third case resulted in growth of the pressure impulse due to the reflection from a rigid obstacle. In the article different hull bottom shapes are compared. The gap between the bottom and the ground is fixed in all cases. Explosion in Euler domain without limitations is added as a reference. The blast wave caused by the detonation (simulated as a point detonation) propagated in cubic mesh with appropriate boundary conditions. Theoretical solution of spherical non-linearity is given in a form of Taylor equations. It was used to verify the numerical model. The research showed that the ground proximity affects the results of the simulation. The pressure impulse is amplified due to the wave reflection from both the bottom of the vehicle and the ground. As well as that, the study confirmed that the usage of the deflector considerably reduces the impact load to the structure.
Źródło:
Journal of KONES; 2011, 18, 1; 39-46
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 16-30 z 126

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