Identyfikatory
Warianty tytułu
Influence of filling of composite tubes with elastomers on absorbed energy and crush mechanism
Języki publikacji
Abstrakty
W pracy przedstawiono wyniki badań doświadczalnych elastomerów o twardościach: 40, 60, 70 i 90 w stopniach określonych metodą Shore'a w skali A. Z badań energochłonnych rurek kompozytowych wypełnionych elastomerami określono wpływ stopnia wypełnienia rurek i twardości elastomeru na wartość pochłanianej energii uderzenia. Przedstawiono też mechanizm niszczenia próbek oraz określono właściwości mechaniczne elastomerów o różnej twardości z prób rozciągania, ściskania i obciążenia okresowo zmiennego.
The paper presents the results of experimental investigations of the influence of filling of the tubes with elastomers on their impact energy absorption capability. Elastomers of 40; 60; 70 and 90 hardnesses in the degrees determined by Shore's method in A scale were investigated. Composite tubes were made of epoxy resin matrix (E-53) reinforced with carbon fabric TENA X HTA (C/E) or glass fabric STR-012-350-110 (S/E) and filled with elastomers of a different filling degree level and hardness. The dimensions of the tubes subjected to the examinations were: diameter ø40 mm and length 50 mm. The degree of filling of the specimens with elastomers is determined by percentage filling of the inner volume of the tube with elastomer of different perforation size (the number and the diameter of the holes made in elastomers). The energy absorbing tests were performed on the testing machine Instron 8802. The specimens placed between two flat plates were compressed at the constant load rate equal to 40 mm/min. The maximal shortening of the specimens was equal to 30 mm. On the basis of these data, the graphs of crush force in terms of the specimen shortening were outlined (load – displacement). The influence of the degree of filling of the composite tubes and the elastomer hardness on the energy absorbing capacity was evaluated from the energy absorbing tests. The paper covers the discussion of the crush mechanism of the specimens. The mechanical properties of elastomers used in the tests were evaluated from axial tension and compression load as well as from changing load tests [3]. The results of the influence of filling of the composite tubes with elastomers with different filling degree and various hardness on EA value are presented in table 2. The results are average values from three tests performed for each kind of the specimen. The table contains the specimens' specification: type of composite, wall thickness, filling degree, elastomers hardness, maximum load, specimens; shortening and absorbed energy (EA). The illustrations (Figs. 3-7) present the exemplary graphs of load versus displacement dependences for various kinds of specimen specifications. The graphs 8 to 10 show dependences of filling degree, hardness, wall thickness and reinforcement type (C/E, S/E) on the energy absorbed by the given specimens (EA). The specimens filled with elastomers show different crush mechanism than the specimens without filling. Tubes without the filling material crush progressively by layer bending mode while the specimens filled with elastomers crush by crack along the side surface of the tube, which is caused by the pressure of the compressed elastomer inside (see Fig. 4). Filling of the C/E and G/E composite tubes with elastomers of different hardness causes the increase in crush force (at an average of 22% for C/E), what can be concluded from the investigation results presented in tables 2 and 3 as well as in Figs. 5-7. Along with the increase in a tubes' filling degree, the tube crush displacements highly decrease, what influences directly the EA value decrease (see Figs. 5 and 6). The C/E composite tubes filled with elastomers show greater EA than the analogical tubes made of S/E composite because C/E composite compression strength is significantly greater. This effect was shown in the tests of C/E and S/E of equal wall thickness (see Fig. 10). However, the EA value was slightly influenced by the hardnesses of elastomers (40°, 60°, 70°, and 90° ShA) which filled the tubes. The influence of the tube wall thickness of polymer composites on EA is increasing for all the examined cases of a tubes filling degree and elastomer hardness. It results from the tubes crushing by the layer bending, as the bending strength depends on the thickness in square. The points presented in Figure 8 indicate the experimental results and the solid lines arose in the result of describing the points with polynomials obtained by the minimum squares method. The approximations of the dependence degree of the filling on the absorbed energy value show that EA increases to the filling degree of about 22%, however, EA significantly decreases when it is over 22%. This effect occurs due to the circumferential stresses caused by the pressure inside the tube, which are induced by the compression of incompressible elastomers.
Czasopismo
Rocznik
Tom
Strony
285--296
Opis fizyczny
Bibliogr. 5 poz.
Twórcy
autor
autor
- Wojskowa Akademia Techniczna, Wydział Mechaniczny, Katedra Mechaniki i Informatyki Stosowanej, 00-908 Warszawa, ul. S. Kaliskiego 2
Bibliografia
- [1] M. Pękalak, S. Radkowski, Gumowe elementy sprężyste, PWN, Warszawa, 1989, 143.
- [2] Guma. Poradnik inżyniera i technika, praca zbiorowa, WNT, Warszawa, 1981.
- [3] S. Ochelski, P. Bogusz, A. Kiczko, Wpływ twardości elastomerów na właściwości mechaniczne, Journal of KONES, XI Konferencja Naukowo-Techniczna: „Programy MES we wspomaganiu analizy, projektowania i wytwarzania”, Pisz, 2009.
- [4] P. Gotowicki, Wytwarzanie próbek do badań właściwości mechanicznych z kompozytów polimerowych, VII Konferencja Naukowo-Techniczna „Polimery i Kompozyty Konstrukcyjne”, Istebna, 2006.
- [5] Normy: PN: PN-ISO 37, PN-54/C-04253, PN-80/C-04290, PN-87/C-04289, PN-78/C-04338.
Typ dokumentu
Bibliografia
Identyfikator YADDA
bwmeta1.element.baztech-article-BWAW-0007-0034
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