Wyniki 1-6 spośród 6 dla zapytania: authorDesc:"Mateusz Kozioł"

Wpływ struktury układów wielowarstwowych na rozwój procesu zniszczenia laminatów

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W wielu odpowiedzialnych konstrukcjach inżynierskich znajdują zastosowanie polimerowe kompozyty włókniste, tworzące układy wielowarstwowe nazywane zwyczajowo laminatami. Ich charakterystyki wytrzymałościowe zależą nie tylko od jakości i ilości łączonych ze sobą komponentów, ale również w dużym stopniu od struktury laminatu. Uwzględniając fakt, że laminat zbudowany jest z warstw kompozytowych[...]

Charakterystyka płyt kompozytowych wytworzonych metodą RTM ze zszywanych preform włókna szklanego

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Jedną z podstawowych metod wytwarzania laminatów kompozytowych jest nasycanie ciśnieniowo-próżniowe w zamkniętej formie RTM (ang. Resin Transfer Moulding).Metoda ta polega na wtryskiwaniu ciekłej żywicy do formy zawierającej odpowiednio przygotowane zbrojenie włókniste (preformę). Zaletą metody RTM jest otrzymywanie wyrobu obustronnie gładkiego, wysoka jakość oraz [...]

Metody wzmacniania laminatów polimerowo-włóknistych w kierunku translaminarnym

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Wielowarstwowe kompozyty włókniste o osnowie polimerowej (laminaty) są szeroko stosowane w konstrukcjach, w których wymagana jest jednocześnie wysoka wytrzymałość mechaniczna i możliwie najmniejsza masa. Jedną z głównych wad tego typu materiałów jest niska wytrzymałość w kierunku prostopadłym do ułożenia warstw zbrojenia (translaminarnym), powodowana przez brak zbrojenia w tymże kierunku. Ob[...]

Behaviour of plain-woven glass-fiber reinforced polymer laminate plates during symmetrical bending on a circular support – Part I: Experimental evaluation DOI:10.15199/28.2018.3.4


  Glass fiber reinforced polymer (GFRP) laminates are increasingly being used as construction materials due to their favourable combination of high strength and low density. GFRP laminate parts are being used in industries such as: automotive [1, 2], maritime [3, 4] and construction [5, 6]. In aviation GFRP composites are being used in primary load-bearing structures [7, 8] and in plating of modern aircrafts [9]. GFRP laminates are often subjected to compound stress states in their use conditions and the parts made from GFRP take the shape of plates or shells [10, 11]. Nonetheless, most of mechanical tests that form the base for designing the above mentioned parts are tests that are conducted in a uniaxial tension or 3- or 4-point bending tests. The shape of components made of composite materials and the compound nature of the loads applied to these components [12] means that the results of the simple mechanical tests are not sufficient to assess the real objects in all cases. One of the possible loads on the shell-like elements is the interaction of the forces perpendicular to their surface as the result of contact with devices or objects in their surroundings, such interactions can be static or dynamic. A strength test that can imitate such a loading case is the symmetrical pressing of a spherical-shaped indenter into the surface of a composite material plate placed on a circular support (Fig. 1). Similar tests carried out under impact load conditions are used for plastic products and consist of impacting a specimen with a drop-weight (described in PN-EN744: 1997P). However, the tests only allow for the analysis of the state of the material after an impact of a certain energy. The indenter pressing test induces compound stress and a strain state in the material. Whereas in the case of static tensile tests, or simple bending tests, the value of the stress which exceeds the particular critical level causing the material to be des[...]

Behaviour of plain-woven glass-fiber reinforced polymer laminate plates during symmetrical bending on a circular support – Part II: Numerical analysis DOI:10.15199/28.2018.4.5


  1. INTRODUCTION A very useful tool for designing laminate structures for use in various constructions is the computer simulation of their behaviour under specific load applications [1, 2]. The finite element method (FEM) is mainly used for this purpose. However, precisely simulating the behaviour of laminates that are subjected to load is still causing many difficulties [3, 4]; it has become an essential part of the manufacturing process — especially for complicated and highloaded products [5, 6]. Over the last few years, many approaches have been developed for mechanical modelling of laminate elements [7, 8], both from the point of view of the laminate (material) itself [9, 10], and from the point of view of the applied stress state [11, 12]. One of the most effective is the non-linear FEM approach using the nine-node Lagrangian elements [13]. The study presents an attempt to assess the strength of the tested materials on the basis of computer modelling methods. A model was developed to analyse stress, strain, and displacement fields in multilayer laminates during the indenter-loading test. The test was performed within the former study entitled “Behaviour of Plain- Woven Glass-Fiber Reinforced Polymer Laminate Plates During Symmetrical Bending on a Circular Support - Part I: Experimental Evaluation" [14]. It should be noted that during the test, as the strength increased, the indenter-laminate plate contact surface area changed. Changes of this surface as a function of time or displacement are difficult to determine experimentally. However, it is possible to estimate its limit values at the beginning and at the end of the test. The axial force applied to the indenter decomposes on the contact surface with the laminate. The use of computer modelling in regard to the contact of the indenter with the plate surface appears to be the most precise method of determining the stress field in a material. The criteria for t[...]

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