Autor: Ochelski, S. - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Crush energy absorption capability of carbon-epoxy and glass-epoxy composites
Zdolność pochłaniania energii uderzenia elementów z kompozytów węgiel/epoksyd i szkło/epoksyd
Autorzy:: Ochelski, S.
Gotowicki, P.
Powiązania:: https://bibliotekanauki.pl/articles/241643.pdf
Data publikacji:: 2007
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: kompozyty polimerowe
energia absorpcji
badania doświadczalne
transport
włókna węglowe
polymer composites
absorption energy
experimental testing
carbon fiber
Opis:: In the paper, experimental investigation of the energy absorption capability of carbon-epoxy and glass-epoxy composites was described. Influence of the following factors on the energy absorption capability was analysed: fibre reinforcement type, kind of structure, geometry and shape of specimens, orientation of fibres in a layer and stacking sequence of layers. Specimens in a shape of tubes and truncated cones were selected for testing. The basic mechanical properties of composites designed for elements of energy absorbing structure, essential for numerical simulation of the failure mechanism during the crash test, were determined experimentally. The favourable effect of the failure initiator, made at the specimen's edge, causing the increase in the specific absorbed energy (SAE), as well as the influence of the thickness of individual layers of the layered composite on the SAE value were also investigated. In the tests for truncated cone specimens, the influences of the specimen's thickness on the SAE value were analysed.
W pracy opisano doświadczalne badania zdolności pochłaniania energii przez kompozyty węglowo-epoksydowe i szklano-epoksydowe, których porównano wyniki badań. Na wartość pochłaniania energii przeanalizowano wpływ, takich czynników jak: rodzaj włókien wzmacniających, rodzaj struktury, geometria i kształty próbek, orientacja włókien w warstwie i sekwencja układania warstw. Przyjęto do badań próbki w postaci rurek i ściętych stożków. Doświadczalnie określono podstawowe właściwości mechaniczne kompozytów, przeznaczonych na elementy konstrukcji energochłonnej, które są niezbędne do numerycznej symulacji mechanizmu niszczenia, występującego podczas badań zdolności pochłaniania energii w czasie uderzenia. Badano też korzystny wpływ inicjatora niszczenia, wykonanego na krawędzi próbki, który powoduje zwiększenie wartości względnej energii absorbowanej (WEA). Zbadano wpływ grubości poszczególnych warstw kompozytu warstwowego na wartość WEA. W badaniach próbek w postaci ściętych stożków, analizowano wpływ grubości ścianki i połówkowego kąta stożka na wartość WEA.
Źródło:: Journal of KONES; 2007, 14, 1; 289-302
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

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

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Skocz do pozycji: 3.

Tytuł:: Influence of hardness on mechanical properties of elastomers
Autorzy:: Ochelski, S.
Bogusz, P.
Kiczko, A.
Powiązania:: https://bibliotekanauki.pl/articles/246003.pdf
Data publikacji:: 2010
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: experimental research
elastomers
mechanical properties
relative damping coefficient
mechanical loss angle
Opis:: In this paper, elastomers with different hardness factors were examined to evaluate the influence of the hardness on their mechanical properties. The following hardness numbers, measured in Shore A hardness scale, were investigated: 40; 60; 70 and 90°. Basic mechanical tests i.e. axial tension and axial compression have been performed in order to calculate elastic properties and stress values corresponding to the fixed strains: epsilon = 0.2; 0.3 and 0.5. The sigma (epsilon) dependences from the tension and compression tests are nonlinear and have different shapes. The tension plot can be described by a convex parabola, while the compression curve can be approximated by a concave one. dynamic load tests with loading freąuencies 0.01; 0.1; 1.0 and 3,OHz were performed in order to determine the hysteresis loop and to obtain force and displacement dependences in time. From those results the following factors were calculated: relative damping coefficient and mechanical loss angle, as well as their dependence on load frequencies. The influence of hardness on both in-phase and out-of-phase components of normal modulus were investigated. The sensitivity of the examined elastomers to the loading rate was also investigated.
Źródło:: Journal of KONES; 2010, 17, 1; 317-325
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

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

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Skocz do pozycji: 5.

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

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Skocz do pozycji: 6.

Tytuł:: Experimental validation of the numerical model of a car impact on a road barrier
Autorzy:: Barnat, W.
Bogusz, P.
Dziewulski, P.
Gieleta, R.
Kiczko, A.
Klasztorny, A.
Klasztorny, M.
Niezgoda, T.
Ochelski, S.
Powiązania:: https://bibliotekanauki.pl/articles/245936.pdf
Data publikacji:: 2010
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: car - road barrier system
crash test
experimental examinations
numerical simulations
numerical model validation
Opis:: This analysis considers the problem related to the transport safety improvement by applying specialized energy absorbing elements. The advanced finite element method was used to solve this problem. The obtained results permit to estimate the practical usability of the proposed solution. In previous works of the examination team [1-5] a series of numerical analysis of the car -- road barrier dynamical system, directed to the elaboration of the numerical model methodology of an impact problem with the use of chosen CAE programs, was submitted. In this article experimental results of a Suzuki Swift car impact into a standard road barrier arę presented. Tests were carried out at the Automotive Industry Institute (PIMOT) in Warsaw, with the use of a test sample of the road barrier. Presented results of experimental tests serve to validation of a numerical model of the aforementioned system. For the safety sake the car's speed during the experimental examinations was limited to 50 km/h. Moreover, the vehicle hit perpendicularly a properly modified road barrier's sector. Experimental initial boundary and constructional conditions were modelled in numerical examinations. in which a commonlv available Suzuki Swift car model, http://www.ncac.gwu.edu, was used. Numerical analysis was carried out with the use of LS-DYNA system.
Źródło:: Journal of KONES; 2010, 17, 1; 17-27
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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