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Wyszukujesz frazę "Mazurkiewicz, L.P." wg kryterium: Autor


Tytuł:
Selected economic factors impacting tourist travel in Poland between 2000 and 2012 and a forecast for 2013-2017
Autorzy:
Kućmierz, P.
Mazurkiewicz, Ł.
Walanus, A.
Tematy:
tourism travel
trip prediction
economic conditionality
Euro 2012
Pokaż więcej
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Powiązania:
https://bibliotekanauki.pl/articles/128458.pdf  Link otwiera się w nowym oknie
Opis:
The paper presents an analysis of tourist travel in Poland during the 2000-2012 time period and predictions for years 2013-2017. Since 2000 the amount of travelling Polish citizens has declined. Various factors may have impacted this state of matters e.g. the economic crisis or increasing the VAT rate. The biggest decline in tourist travel was observed between 2007 and 2009 and in 2011. On the other hand, the factor which increased the number of visits between 2007 and 2009 may have been the Euro 2012 championship, organized by both Poland and Ukraine. The paper presents a "eurosensitivity" factor, which describes the increase in people visiting selected voivodeships during 2012, primarily due to the Euro 2012 championship. According to the calculations, the voivodeship which benefited from the highest increase was Małopolska. The article also presents an estimation of travel for years 2013-2017.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Identification of layers distribution in the composite coupon using finite element method and three point bending test
Autorzy:
Mazurkiewicz, Ł.
Małachowski, J.
Damaziak, K.
Baranowski, P.
Gotowicki, P.
Tematy:
fibre reinforced composite
FE analysis
hand lay-up technique
experimental validation
kompozyt włóknisty
analiza elementów skończonych
weryfikacja doświadczalna
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Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Powiązania:
https://bibliotekanauki.pl/articles/387164.pdf  Link otwiera się w nowym oknie
Opis:
The main objective of the study is to develop experimentally validated FE model and perform numerical analysis of layered composites made by hand lay-up techniques during tension and bending test. The research object is glass - polyester laminate made of four unidirectional layers. In order to validate the numerical models experimental test were performed. Due to the very different stiffness modulus in tension and bending loading the material properties obtained from standard test are not suitable to apply in numerical model. Significantly different behaviour compared to experimental test was obtained for tree point bending where the numerical model becomes too stiff. Simple coupons, relatively easy to manufacture presented in the paper have very low quality. The differences in actual and theoretical bending stiffness (obtained from tension stiffness) exceed 70%. In order to represent the actual structure the layers of the composite were divided by resin layers and also additional resin layer at the top and bottom of the model were defined. Single stage optimization process was used to adjust the material layout. After layer set-up modification very significant improvement can be seen for flexural behaviour.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of numerical testing methods in terms of impulse loading applied to structural elements
Autorzy:
Mazurkiewicz, Ł.
Małachowski, J.
Baranowski, P.
Damaziak, K.
Tematy:
blast wave
FEM
Eulerian mesh
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Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Powiązania:
https://bibliotekanauki.pl/articles/280777.pdf  Link otwiera się w nowym oknie
Opis:
This paper presents comparison of numerical testing methods of an impulse loading which comes from a detonation process, i.e. blast wave propagation in a gas medium. Investigations were carried out using an analytical and numerical model based on the Finite Element Method. In order to reduce computational time, the substitute analytical model with one degree of freedom was implemented, which replaced a chosen actual system (I-section steel column). For structure modelling, the constitutive model was used, which included the strain rate effect. From the performed analyses, an acceptable similarity was noticed, although the discrete model due to greater forces gave inflated results. Nevertheless, it should be pointed out that simplified methods do not take any wave and flow around effects into consideration, which have an influence on the dynamical response of the structure and are possible to implement in the gas medium coupling.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of the forces developing in the straps of the belts that restrain a child in a safety seat
Analiza sił działających w taśmach pasów podtrzymujących dziecko w foteliku bezpieczeństwa
Autorzy:
Muszyński, A.
Trzaska, P.
Wicher, J.
Mazurkiewicz, Ł.
Tematy:
passive safety
child safety seats
seat belt straps
bezpieczeństwo bierne
samochodowe foteliki bezpieczeństwa
taśmy pasów bezpieczeństwa
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Wydawca:
Sieć Badawcza Łukasiewicz. Przemysłowy Instytut Motoryzacji
Powiązania:
https://bibliotekanauki.pl/articles/1363938.pdf  Link otwiera się w nowym oknie
Opis:
The paper comprises the most important observations concerning the appropriate use of child car seats, with special attention being given to seat belt straps, which are among the critical elements of the child restraint system. The appropriate positioning and pre-tensioning of the child restraining straps and the most frequent faults in using the belts have been highlighted. Results of strength tests of belt straps of 25.4×1.56 mm and 38.6×1.23 mm cross-section (narrow belts and wide belts, respectively) have been presented. The time histories and distribution of forces in the shoulder and lap belts restraining a child with a mass of 15 kg were examined. Two types of child safety seats, referred to as “safety seat 1” and “safety seat 2”, were used. A car crash was simulated by braking a measuring trolley from a velocity of 50–52 km with a deceleration of up to 28 g. The distribution of forces in the shoulder and hip belts of the harness restraining a test dummy was analysed. The force distribution was found to depend on the seat construction. The test results and graphs presented indicate a possibility of evaluating the effectiveness of child safety seats in the car collision phase.
W artykule przedstawiono najważniejsze spostrzeżenia dotyczące właściwej eksploatacji fotelików bezpieczeństwa dla dzieci, ze szczególnym uwzględnieniem taśm stanowiących ważny element systemu mocowania dziecka. Zwrócono uwagę na prawidłowe położenie i wstępny naciąg taśm mocujących dziecko oraz najczęściej występujące nieprawidłowości eksploatacyjne. Przedstawiono wyniki badań wytrzymałościowych taśm o przekroju: 25,4 x 1,56 mm (pasy wąskie) i 38,6 x 1,23 mm (pasy szerokie). Badano przebiegi i rozkład sił w pasach barkowych i biodrowych przytrzymujących manekin dziecka o masie 15kg. Użyto dwóch rodzajów fotelików bezpieczeństwa, zwanych dalej Fotelik 1 i Fotelik 2. Symulację zderzenia samochodu uzyskano w wyniku hamowania wózka pomiarowego z prędkości 50-52 km/h osiągającego opóźnienie 28g. Przeprowadzono analizę rozkładu sił w pasie barkowym i biodrowym manekina. Stwierdzono, że rozkład tych sił zależy od rozwiązania konstrukcyjnego fotelika. Przedstawione wyniki badań i wykresy wskazują na możliwość oceny efektywności fotelików w fazie zderzenia samochodu.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamic testing of copper material : numerical approach
Autorzy:
Baranowski, P.
Małachowski, J.
Mazurkiewicz, Ł.
Damaziak, K.
Tematy:
miedź
sprężanie
analiza elementów skończonych
SHPB
copper
compression
FE analysis
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Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Powiązania:
https://bibliotekanauki.pl/articles/387353.pdf  Link otwiera się w nowym oknie
Opis:
Split Hopkinson pressure bar (SHPB) is one of the most important and recognisable apparatus used for characterizing the dynamic behaviour of various materials. Incident pulse generated one the incident bar usually have a rectangular shape, which is proper for some materials but for others is not. Therefore, several methods of shaping the incident pulse are used for obtaining constant strain rate conditions during tests. Very often pulse shapers made of copper or similar material are implemented due to its softness properties. In this paper such material was investigated using the FE model of SHPB. Its mechanical behaviour was characterised with and without copper disc between the striker and incident bar. Numerical simulations were carried out using explicit LS-DYNA code. Two different methods were used for modelling the copper sample: typical finite Lagrangian elements and meshless Smoothed Particle Hydrodynamics (SPH) method. As a result of two techniques used axial stress-strain characteristics were compared for three different striker’s velocity with an influence of the copper pulse shaper taking into account. Finally, FE and SPH method was compared with taking into consideration: the efficiency, computer memory and power requirements, complexity of methods and time of simulation.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical analysis of I-beam supporting structure with multimaterial protective panel - parametric study
Autorzy:
Damaziak, K.
Mazurkiewicz, Ł.
Małachowski, J.
Klasztorny, M.
Baranowski, P.
Tematy:
ALE formulation
blast wave
dynamic response
protective panel
Pokaż więcej
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Powiązania:
https://bibliotekanauki.pl/articles/246508.pdf  Link otwiera się w nowym oknie
Opis:
Dynamic response of an I-beam supporting structure subjected to shock wave produced by the detonation of high explosive materials is presented in this paper. Dynamic response of structural components in different load cases-with multimaterial panel protection and without protection, subjected to blast wave from various charge weight and various distance stand-off was determined. LS-DYNA, a 3-D explicit, finite element computer code with Lagrangian-Eulerian coupling was used to study this behaviour. Also initial static load was taken into account as pre-stress field present in the column obtained using dynamic relaxation procedure. The protective panel is composed of fibreglass composite and aluminium foam. The composite orthotropic properties and the failure criteria for fibre and matrix damage as well as the stress-volumetric strain curve for metallic foam were taken into account. The previous study shows that critical to the structure durability are the plastic strains and the structure failure caused by high deformation. Results of the analyses indicate that application of the blast panel around the supporting structure increase the resistance and significantly reduce the plastic deformation of the structure. The pillar without protection can be destroyed by 2 kg TNT placed close to the structure. Analysed beam covered by the blast panel can resist over three times bigger charge without significant deformation of the structure.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of remote sensing indices in determining the interrelation between condition of tree stands and myrmecofauna in forests of Wigry National Park
Autorzy:
Chiliński, M.T.
Czajkowska, K.
Krzysztofiak, L.
Mazurkiewicz, P.J.
Tematy:
red wood ants
myrmecofauna
forest ecosystems
vegetation indices
remote sensing
RPAS
drone
NDVI
Pokaż więcej
Wydawca:
Uniwersytet Przyrodniczy w Poznaniu
Powiązania:
https://bibliotekanauki.pl/articles/2130428.pdf  Link otwiera się w nowym oknie
Opis:
Presented work is aimed at investigating potential correlations between remote sensing vegetation indices and local ant populations. Research was conducted in summer of 2017 in Wigry National Park in two types of forest habitats: coniferous (Serratulo-Pinetum) and deciduous (Tilio-Carpinetum). NDVI and MCARI2 vegetation indices were measured with the use of a drone and yielded comparable correlations with ant-related quantities. We determined that the presence of ants from Formica group is positively correlated with vegetation indices, while the correlation between Myrmica and Lasius ants and vegetation indices is more complex.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical study for determination of pulse shaping design variables in SHPB apparatus
Autorzy:
Baranowski, P.
Malachowski, J.
Gieleta, R.
Damaziak, K.
Mazurkiewicz, L.
Kolodziejczyk, D.
Tematy:
Split-Hopkinson Pressure Bar
pulse shape
numerical studies
parametrical study
Pokaż więcej
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:
https://bibliotekanauki.pl/articles/200666.pdf  Link otwiera się w nowym oknie
Opis:
High strain rate experimental tests are essential in a development process of materials under strongly dynamic conditions. For such a dynamic loading the Split Hopkinson Pressure Bar (SHPB) has been widely used to investigate dynamic behaviour of various materials. It was found that for different materials various shapes of a generated wave are desired. This paper presents a parametric study of Split Hopkinson Pressure Bar in order to find striker’s design variables, which influence the pulse peak shape in the incident bar. With experimental data given it was possible to verify the developed numerical model, which was used for presented investigations. Dynamic numerical simulations were performed using explicit LS-Dyna code with a quasi-optimization process carried out using LS-Opt software in order to find striker’s design variables, which influence the pulse peak shape.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Load carrying capacity numerical study of I-beam pillar structure with blast protective panel
Autorzy:
Mazurkiewicz, L.
Kolodziejczyk, D.
Damaziak, K.
Malachowski, J.
Klasztorny, M.
Baranowski, P.
Tematy:
FE analysis
blast protection
stability study
Pokaż więcej
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:
https://bibliotekanauki.pl/articles/202056.pdf  Link otwiera się w nowym oknie
Opis:
The paper presents numerical analyses aimed at preliminary assessment of the protective panel effectiveness, which task is to protect the elements of building structures against explosion. For the criterion of assessing the effectiveness of the panel the load capacity of the column made of steel I-beam was chosen. Ultimate force was determined by using advanced computational procedure, which consisted of four stages: preload, blast simulation, dynamic response and static analysis of deformed structure. Blast load was simulated using Lagrangian- Eulerian domain coupling. Results indicated that the application of the protective panel significantly reduces the plastic deformation of the structure.
Dostawca treści:
Biblioteka Nauki
Artykuł

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