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Wyświetlanie 1-12 z 12
Tytuł:
Investigations of composite energy absorbing elements
Autorzy:
Niezgoda, T.
Barnat, W.
Kiczko, A.
Powiązania:
https://bibliotekanauki.pl/articles/243633.pdf
Data publikacji:
2008
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
impact test
FEM simulation
passive safety
composite structure
energy absorbing materials
Opis:
In this work the problem connected with an improvement of the road safety through implementation of additional elements absorbing the hitting energy is taken into consideration. The experimental results of a basic absorbing element of the glass epoxy composite are presented. The results of these tests will serve for the construction of a reliable numerical model of a panel of protective elements. The coincidence between the experimental and numerical results is also proved, showing that introduced approach to the modelling of the process of the progressive destruction and the energy absorption by composite elements is not only properly assumed but is very promising for the future. Efforts, which lead to increase the amount of absorbed energy need actions, directed to improving absorbing energy properties of used elements. Therefore, the received results will serve as guidelines for elaboration the methodology of the research structures of that type and also could be used in further research works within the scope of increasing the road security. In the article it is also proved that there is the necessity to conduct the series of comparative experiments and also tests verifying numerical studies at loading speeds, which can be compared with ones in reality, e.g. crash test or shock wave of an explosion. The validated, in such way, method of numerical simulations enables the limitation of costly and long-lasting research of real objects.
Źródło:
Journal of KONES; 2008, 15, 3; 405-409
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental support for numerical simulations of energy absorbing structures
Autorzy:
Ochelski, S.
Gotowicki, P.
Powiązania:
https://bibliotekanauki.pl/articles/243303.pdf
Data publikacji:
2008
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
polymer composites
energy absorbing structures
sandwich structures
specific energy absorption
experimental methods
Opis:
This paper presents experimental investigations of mechanical properties of materials used in the absorbing energy structures. Numerous experimental investigations are essential to develop a reliable numerical model of composite structures absorbing the impact energy. This model should correctly describe the dissipation of kinetic impact energy in the progressive crush process. Mechanical properties of composite materials like elastic modulus, strength, failure strains with influence of anisotropic properties are obtained experimentally. Different strength hypotheses are used for fibrous composites. The investigations on the complex stress state allow determining which of these theories describes the composite best. It was proved that both the matrix type and the structure of the composite have a very large influence on the SEA (Specific Energy Absorption), in particular on their crack propagation resistance. The dependence between the energy absorbed by a single energy absorbing element and a fragment of the structure absorbing the impact energy was discussed. Friction forces play the important role in the progressive crush of composites and they should be taken into account in developing a valid numerical model. Some authors state that the friction forces absorb 40% of the impact energy. The influence of failure strain rates on the absorbing energy capability, which is not clearly defined in the literature about composite structures, was also discussed.
Źródło:
Journal of KONES; 2008, 15, 1; 183-217
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical analysis of progressive failure of composite energy absorbing structures
Autorzy:
Niezgoda, T.
Barnat, W.
Powiązania:
https://bibliotekanauki.pl/articles/243301.pdf
Data publikacji:
2008
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
transport safety
road barriers
numerical analysis
energy-absorbing element
FEM
Opis:
The aim of the paper was to compare the influence of the applied fill on the energy absorbed by the energy ubsorbing structural elements made of composite, steel and from composite with fill foam. The experimental tests were carried out on an INSTRON universal testing machine at the speed rate of the machine's traverse equal 10 mm/min md the numerical analysis has been performed using MSC. Dytran software based on the Finite Element Method. The elements were subjected to axial kinematic loads. The higher specific absorbed energy occurs in the case of energy absorbing elements made of composites and from composite with fill foam. These elements can be applied in structures designed for the protection of people or limitation of the whole structure failure, e.g. in the case of a helicopter or car crash etc. The failure progressing in a relatively uniform manner results in the fact that the work md for failure of an energy absorbing element causes a substantial reduction of the impact load results. Application of energy absorbing elements may be a system dissipating the energy of a car impact into a crash barrier. The results of numerical simulation of stiffness plate hitting to the road barrier are presented. Experimental tests and numerical simulations were also presented for a composite sleeve subjected to progressive failure, which allowed carrying out simulation and analysis of a crash into a road barrier protected by a system of two such sleeves.
Źródło:
Journal of KONES; 2008, 15, 1; 169-181
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of influence of the shape of protective structures on their energy-absorbing capabilities
Analiza wpływu kształtu struktur ochronnych na ich energochłonność
Autorzy:
Barnat, W.
Niezgoda, T.
Powiązania:
https://bibliotekanauki.pl/articles/241729.pdf
Data publikacji:
2007
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
wpływ kształtu na energochłonność
impuls ciśnienia
energochłonność
influence of shape on energy-absorbing capability
pressure impulse
energy-absorbing capabilities
Opis:
The paper presents results of numerical investigation of the influence of the shape of a protective element on its energy-absorbing capabilities from the point of view of its resistance to the impact of a shock wave. The works carried out so far confirm that-- as far as the energy-absorbing capabilities are concerned - the shape of the protective element is an important factor. In the paper, results of numerical analysis of basic protective structures in the shape of pyramids, cones and hemispheres were presented. In the numerical models under consideration, dimensions of the base and height of the element were settled. The shape of the base determines the lateral surface of a cone. For the settled dimensions, a cone has the smallest area of the lateral surface and a sphere - the largest. For the models of basic structures, computations were performed with the use of the Dytran programme. As a result of the analysis, deformation of the structures, energy of deformation, velocities and accelerations were obtained. In the paper, a criterion for the assessment of energy absorption capabilities was proposed. It consisted in comparing the results for plates with a protection structure with those for a basic smooth plate in order to assess the level of energy absorbed by the protected plate with respect to the basic one (without protection).The comparison of results for the basic plate and the one with a spherical element shows that the application of the structure would cause the relative displacement of the plate protected a spherical element 50 percent lower than the relative displacement of the plate without protection.
W niniejszym artykule przedstawiono wyniki z przeprowadzonych badań numerycznych nad wpływem kształtu elementu ochronnego na energochłonność pod kątem odporności na działanie fali uderzeniowej. Dotychczasowe prace nad elementami energochłonnymi potwierdzają, iż dość ważnym z punktu widzenia energochłonności jest kształt elementu energochłonnego. W artykule przedstawiono wyniki z analizy numerycznej podstawowych struktur energochłonnych w postaci ostrosłupów stożków i półsfery. W modelach numerycznych ustalono wielkość podstawy oraz wysokość elementu struktury. Kształt podstawy determinuje pole powierzchni elementu. Najmniejsze pole powierzchni bocznej ma stożek. Największe pole powierzchni charakteryzuje sferę. Dla modeli struktur podstawowych wykonano obliczenia programem Dytran. W wyniku analizy numerycznej otrzymano postacie deformacji struktur, energię odkształcenia prędkości oraz przyspieszenia. W pracy przyjęto kryterium oceny energochłonności, polegające na porównaniu wyników płyt ze strukturą ochronną z płytą bazową gładką, w celu oceny zmiany poziomu energii pochłoniętej przez płytę zabezpieczoną w stosunku do płyty bazowej (bez zabezpieczenia). Porównanie wyników dla blachy bazowej i blachy z elementem sferycznym pokazuje, że zastosowane struktury powodowały względne przemieszczenie węzła płyty chronionej elementem sferycznym mniejsze o 50% od względnego przemieszczenia płyty.
Źródło:
Journal of KONES; 2007, 14, 1; 15-26
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of energy-absorbing capabilities of flexible elements in the aspect of applied materials
Badania energochłonności elementów podatnych w aspekcie zastosowanych materiałów
Autorzy:
Barnat, W.
Niezgoda, T.
Powiązania:
https://bibliotekanauki.pl/articles/241727.pdf
Data publikacji:
2007
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
bezpieczeństwo transportu
elementy energochłonne
wpływ materiału na energochłonność
transport security
energy-absorbing element
influence of material on energy-absorbing capabilities
Opis:
The paper deals with the problem of improvement of transport security through application of additional elements absorbing the crash energy. Experimental tests and numerical simulations of basic energy-absorbing elements in a shape of a sleeve made of steel, duralumin, bronze and glass-epoxy composite were presented. The results of the investigation will be used to develop a reliable numerical model of a panel of protective elements. The numerical analysis was carried out by the Finite Element Method using the DYTRAN code. The calculations were verified experimentally on a universal testing machine INSTRON in the Department of General Mechanics of the Military University of Technology. On the basis of results of numerical and experimental investigations it was found that the composite sleeves have the specific absorbed energy twice higher than the steel ones. An interesting supplement of the energy dissipating system would be an additional element in the form of foams. It follows from the numerical calculation results that a higher specific absorbed energy was obtained for the composite energy absorbing element with filler. The proposed method, based on numerical investigation, will allow for eliminating expensive and long-lasting testing of real objects. The obtained results will serve as guidelines to develop methods of testing for such structures and can be used in further research on increasing the security level in road transport.
W pracy rozważono problem związany z poprawą bezpieczeństwa transportu przez zastosowanie dodatkowych elementów absorbujących energię uderzenia. Przedstawiono wyniki badań eksperymentalnych oraz symulacji numerycznych podstawowego elementu energochłonnego w postaci tulejki wykonanej ze stali, duraluminium, mosiądzu i kompozytu szklano epoksydowego. Wyniki tych badań posłużą do zbudowania wiarygodnego modelu numerycznego panelu elementów ochronnych. Analizę numeryczną wykonano metodą elektów skończonych w oprogramowaniu DYTRAN. Przeprowadzone obliczenia zostały zweryfikowane eksperymentalnie na maszynie wytrzymałościowej INSTRON w Zakładzie Mechaniki Ogólnej WAT. W wyniku badań numerycznych i eksperymentalnych stwierdzono, iż tulejki kompozytowe mają dwukrotnie większą względną energię absorpcji niż tulejki stalowe. Interesującym jest uzupełnienie układu rozpraszającego energię o dodatkowy element w postaci pian. W wyniku obliczeń numerycznych stwierdzono, iż względną maksymalną energię odkształcenia uzyskano dla kompozytowego elementu energochłonnego z wypełniaczem. Proponowana metoda oparta na badaniach numerycznych pozwoli na wyeliminowanie kosztownych i długotrwałych badań rzeczywistych obiektów. Otrzymane wyniki posłużą jako wytyczne do opracowania metodyki badania tego typu struktur i będą mogły być wykorzystywane w dalszych pracach badawczych w zakresie zwiększenia poziomu bezpieczeństwa w transporcie drogowym.
Źródło:
Journal of KONES; 2007, 14, 1; 27-38
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical-experimental investigation of failure energy of composite energy absorbing panels
Numeryczno doświadczalne badanie energii zniszczenia podstawowych struktur kompozytowych
Autorzy:
Niezgoda, T.
Barnat, W.
Powiązania:
https://bibliotekanauki.pl/articles/242802.pdf
Data publikacji:
2007
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
transport
elementy energochłonne
kompozyty
modele numeryczne
analiza numeryczna
energy absorbing elements
composites
numeric models
numerical analysis
Opis:
The aim of the paper is an assessment of the influence of the applied fill on the energy absorbing capabilities of a composite element of a thin-walled structure under dynamic load. The experimental tests were carried out on the INSTRON universal testing machine. The analysis concerned energy absorbing elements in a shape of sleeves with additional foam fill. The numeric model charge was made like in previously carried out experiments, using cinematic input function. Analysed models were charged by a rigid plate, described by a material MATRIG type. Foam filler use had for result the energy absorption improvement; this is important in the case of modernisation of existing structures using foam filler. An important advantage of energy absorbing elements made of composite materials is their little mass. In the case of considering of protection elements for aviation industry, this factor is very important. The presented results are preliminary tests of energy absorbing filler choice and will be applied for numeric models validation. The conclusion of preliminary estimation of obtained elements is that the appropriate choice of filler material will permit to obtain more important energy necessary for destruction of energy absorbing structure. The future application of numeric analyse will facilitate the process of filler parameters optimisation.
Źródło:
Journal of KONES; 2007, 14, 4; 307-318
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of austenitic steels in energy absorbing structures
Autorzy:
Moćko, W.
Powiązania:
https://bibliotekanauki.pl/articles/246772.pdf
Data publikacji:
2012
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
aluminium alloys
CO2 emission
electric vehicle
vehicle structure
Opis:
Occupants protection during vehicle crash is one of the major problems considered at vehicle designing stage. The increasing safety as well as comfort requirements results in the total vehicle weight increase. On the other hand, higher mass influence on the fuel economy of vehicle. Thus, it is very important to maintain or even reduce vehicle weight. One of the solutions of this problem is application of a new materials having good strength-to-weight ratio i.e. high strength steels (HSS). They are often used in protective and energy absorbing structures in automotive industry. One of HSS so-called austenitic steels are characterized by excellent mechanical properties such as: high strength, strong strain, and strain rate hardening. Those mechanical effects are consequence of microstructural evolution during strong deformations i.e. twinning and phase transformation. As a consequence those steels are very good material for the purposes of energy absorbing and protective structures. This article presents the results of mechanical properties tests of VP159 austenitic steel. On the basis of experimental data, the JC constitutive model has been calibrated. The obtained results were used for the computer simulations of energy absorbing of square profiles made of analysed material. The results were compared with other types of steel.
Źródło:
Journal of KONES; 2012, 19, 3; 305-310
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Composite-polymer materials for energy-absorbing structures
Autorzy:
Barnat, W.
Niezgoda, T.
Ochelski, S.
Powiązania:
https://bibliotekanauki.pl/articles/246205.pdf
Data publikacji:
2009
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
energy absorption structures
safety
composites
numerical simulation
energy absorption investigations
Opis:
On the basis of the results obtained from our own experimental investigations of energy- absorbing elements, the influence of the given factors on absorbed energy (WEA) was determined. The objects of the research were the samples made of epoxy composites reinforced with glass fibres formed in roving, roving stripes and glass mat as well as with carbon fibres formed in roving and carbon roving stripes. To investigate the capability of hitting energy absorption of the samples in the shape of tubes, the truncate cones and in the shape of a thin cuboid were taken under consideration. The sample in the shape of tubes, wavy coats and thin cuboids with angle 45° (on one edge), play the role of the initiator of progressive destruction process. The composites matrix was taken into account during investigations: epoxy, the vinyl-esters, polyetheretherketones, reinforced with carbon and glass fibres with different structures of the samples. The influence of the sample geometry and the orientation of the layers in carbon / epoxide and the ar amid / the epoxide composites on the WEA absorption value were presented in the papers. The comparison of the structures made f rom single elements with relevant structures of four elements shows that absorbed energy is accumulating. In this case the relative absorbed energy remains at the similar level.
Źródło:
Journal of KONES; 2009, 16, 1; 21-34
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental and numerical investigation of connector with elastomer joint
Autorzy:
Sławiński, G.
Malesa, P.
Świerczewski, M.
Bogusz, P.
Powiązania:
https://bibliotekanauki.pl/articles/243074.pdf
Data publikacji:
2017
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
elastomer
energy absorbing
LS-DYNA
experimental tests
FEM analysis
Opis:
This article presents works associated with the design, numerical analyses and experimental tests of an energyabsorbing mat designed for increasing the safety of the soldiers inside military vehicles, especially their legs. One of the most important branches of engineering interests is high technologies accompanying the safety of soldiers. Energy absorbing mats are one of an additional equipment of a military vehicle, which is directly targeted to increase leg safety during explosion of IED (Improvised Explosive Device) under vehicle. The presented invention allows protection legs of the crew’s feet resting on the floor of the vehicle during explosion of a mine or IED. In most solutions, crewmembers’ foot rests directly on the floor, causing serious injuries. The value of the load on the metatarsus and tibia is closely related to the overall vehicle structure, which generally has limitations in the use of available external and internal protection solutions. Energy absorbing mats are a universal solution because they are adaptable to any type of vehicle. Their role is particularly important in flat-bottomed armoured vehicles. The article will show the results of the analysis showing how the mat works. Experimental results will be compared with the results of numerical analysis. The analysis is conducted using the LS-DYNA explicit code.
Źródło:
Journal of KONES; 2017, 24, 3; 283-289
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental evaluation of energy absorbing properties of selected elastomer materials
Autorzy:
Stankiewicz, M.
Popławski, A.
Bogusz, P.
Gieleta, R.
Sławiński, G.
Powiązania:
https://bibliotekanauki.pl/articles/247562.pdf
Data publikacji:
2015
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
material research
experiment
elastomers
polyurethanes
energy absorption properties
Opis:
The paper presents identifying studies of mechanical properties of the selected materials from the group of elastomers including Asmathane (65 ShA), Easyprene FPS (30 ShA), Biresin (U1305). The tests were carried out at the Laboratory of Strength of Materials, the Department of Mechanics and Applied Computer Science, with the use of an especially designed stand for testing the energy absorption of materials. The research aims were to determine the basic properties and characteristics of the selected materials as well as to compare them and identify the material with the best energy-absorbing characteristics. For a single load-unload cycle, applied dynamically, the hysteresis loops were recorded. Energy-absorption of individual materials and maximum strength were determined. During the experimental test, a fast speed camera was used for accurately register the progress performance of the test. The pictures of the dynamic tests of materials behaviour are shown. The curves of the tested materials are compared in the graphs. The resulting data will help to create constitutive models of the tested materials, which in the next stages of the project will be used in numerical studies on the impact of detonation on the designed protective panel.
Źródło:
Journal of KONES; 2015, 22, 3; 241-248
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental-numerical analysis of steel - foam energy - absorbing panels for road barriers modernization
Autorzy:
Niezgoda, T.
Ochelski, S.
Klasztorny, M.
Barnat, W.
Kiczko, A.
Dziewulski, P.
Powiązania:
https://bibliotekanauki.pl/articles/246007.pdf
Data publikacji:
2010
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
numerical simulations
road transport
road barriers
passive safety
Opis:
The works on steel -foam energy-absorbing structures for the road barrier W-beam guardrail were carried out because of the necessity of increasing the passive safety of road barriers [1-5]. A road barrier guardrail is made of steel sections. These types of sections are characterized by good strain properties, although their energy-absorbing abilities and possibilities for "softer" vehicle impact energy are unsatisfactory. In order to increase energy-absorption on the road barrier guardrail additional tin-foam sections were used. Experimental tests on the modifled road barrier guardrail were carried out on a testing machine INSTRON at the Faculty of Mechanics and Applied Informatics of the Military Academy of Technology. Two meters long W-beam guardrail was investigated in a three point bending test, perpendicularly and under the angle of 20°. As a result of the experimental research diagrams of dependence of bending force on displacement were obtained. On the basis of aforementioned diagrams the energy that was absorbed by individual road barrier elements: tin coating, foam insert and steel guardrail, was estimated. Obtained results of the experimental research were also compared with the results of the numerical simulation of the finite elements method in LS-DYNA system.
Źródło:
Journal of KONES; 2010, 17, 1; 309-315
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Computer modelling of energy absorbing capability of bus superstructure for rollover safety
Autorzy:
Nurhadi, I.
Zain, R.
Mihradi, S.
Soe Oo, K.
Powiązania:
https://bibliotekanauki.pl/articles/242230.pdf
Data publikacji:
2011
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
ECE R66
bus superstructure
rollover test
residual space
FEA
quasi-static incremental loading
elastic-plastic
Opis:
This paper describes further investigations that have been carried out to make the proposed procedure [5] becomes more reliable to be practically applied as a requirement in bus type approval. One important aspect highlighted in this paper is an effort to improve the accuracy of the FEA model by taking into account detailed construction of bus superstructure. It worth to note that, based on survey carried out on several bus manufacturers, the detailed construction may vary from manufacturer to manufacturer. As a case study, a bus superstructure from a prominent manufacturer was chosen as a sample. Energy absorbing capacity of a bus superstructure section consisting of four bays including rear entrance door, emergency door and rear end was investigated through elastic-plastic finite element model. Incremental quasy static load according to ECE R66 was applied, subsequently to the right and left cantrail to obtain load deflection curve. Then the energy absorbing capacity of the structure when residual space limit was reached was evaluated through derived energy deflection curve. Essential components of the bus superstructure governing its energy absorbing capacity will be discussed. Modeling strategy in dealing with elastic-plastic analysis for such a rather complex structure is also highlighted.
Źródło:
Journal of KONES; 2011, 18, 2; 331-338
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-12 z 12

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