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  1. 5 Teka Komisji Motoryzacji i Energetyki Rolnictwa
  2. 2 Inżynieria Rolnicza
  3. 2 Przegląd Papierniczy
  4. 2 Zeszyty Naukowe Politechniki Rzeszowskiej. Budownictwo i Inżynieria Środowiska
  5. 1 AGH Drilling, Oil, Gas
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  1. 1 2023
  2. 1 2020
  3. 1 2018
  4. 1 2017
  5. 5 2015
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  1. 5 Gladyszewska B.
  2. 3 Ciupak A.
  3. 3 Stankiewicz A.
  4. 1 Adjei P.
  5. 1 Bocko J.
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1
Content available Application of finite element method for analysis of nanostructures
100%
Bocko J. , Lengvarský P.
Acta Mechanica et Automatica
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2017
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tom Vol. 11, no. 2
116--120
EN
The paper deals with application of the finite element method in modelling and simulation of nanostructures. The finite element model is based on beam elements with stiffness properties gained from the quantum mechanics and nonlinear spring elements with forcedisplacement relation are gained from Morse potential. Several basic mechanical properties of structures are computed by homogenization of nanostructure, e.g. Young's modulus, Poisson's ratio. The problems connecting with geometrical parameters of nanostructures are considered and their influences to resulting homogenized quantities are mentioned.
2
Content available remote Poisson's ratio of a soft sphere system
100%
Tretiakov K. V. , Wojciechowski K. W.
Materials Science Poland
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2007
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tom Vol. 25, No. 2
541--544
EN
Monte Carlo simulations of soft spheres interacting through inverse power potentials, u(r)??r-n, have been performed. Poisson's ratio of the soft sphere face-centred cubic crystals were determined using the constant pressure ensemble with variable box shape. It was shown that at high densities, particle motions decrease Poisson's ratio with respect to the static case which corresponds to zero temperature. It was also shown that increasing the exponent n in the potential, one can decrease Poisson's ratio.
3
Content available Geomechanical properties of shale rock from Baltic Basin in Poland area
88%
Laura A.
AGH Drilling, Oil, Gas
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2015
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tom Vol. 32, no. 2
369--380
EN
The successful development of shale gas requires a fundamental understanding of shales and that can be challenging because these rocks vary significantly. For recoverable shale gas resources assessment a broad range of geological, geochemical, geophysical and geomechanical data is required. Information about the variable lithologies, mineralogies, and kerogen content is vital to locate favorable intervals for gas production. Knowledge of the in-situ stresses and porosity of these intervals is essential for developing hydraulic fracturing strategies to recover the gas in place. Geomechanical properties of shales are important in terms of determination of the likelihood of fractures initiating and propagating in shale materials. Geomechanical properties of rock include: Poisson's Ratio, Total Minimum Horizontal Stress, Bulk, Young and Shear Modulus. These properties play significant role in developing shale assets. Having access to geomechanical data can assist engineers and geoscientists during geomechanical modeling, hydraulic fracture treatment design and in some cases during reservoir modeling in shale gas fields. This paper is intended to give characterization of geomechanical properties of shale rock. It then refers to a case study of Baltic Basin of shale gas in Poland, for discussing it geological condition and rock properties.
4
Wytworzenie i badanie elastycznej pianki poliuretanowej o ujemnym współczynniku Poissona
75%
Lisiecki J. , Błażejewicz T. , Kłysz S. , Gmurczyk G.
Modelowanie Inżynierskie
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2011
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tom T. 11, nr 42
241-248
PL
Modyfikując strukturę komórkową pianki poliuretanowej, można osiągnąć budowę auksetyczną. Odmienne właściwości użytkowe takich materiałów wynikają z ich podstawowej właściwości fizycznej, jaką jest ujemny współczynnik Poissona. Ze względu na planowane zastosowanie pianek auksetycznych na elementy siedzeń śmigłowców wojskowych, do oceny materiału na siedziska i oparcia niezbędna jest znajomość ich charakterystyk materiałowych. W Instytucie Technicznym Wojsk Lotniczych przeprowadzono próbę otrzymywania pianek auksetycznych z pianek o komórkach otwartych, a także przeprowadzono wstępne testy.
EN
By modifying the cellular structure of foam, auxetic structure can be achieved. The difference in properties are due to their basic physical property, which is a negative Poisson's ratio. Due to the planned use of auxetic foam on the seat elements of military helicopters, it is necessary to know the characteristics of those materials. Therefore, the Air Force Institute of Technology performed preparation of open cells, auxetic foams, and necessary, preliminary tests. The article describes the program, its aims and stages of implementation.
5
Content available remote Vibration of skew plate with circular variation in thickness and Poisson’s ratio
75%
Sharma A.
|
2018
|
tom Vol. 22, nr 1
49--58
EN
The present study analyzes the natural vibration of non homogeneous visco elastic skew plate (parallelogram plate) with non uniform thickness under temperature field. Here non homogeneity in the plate's material arises due to circular variation in Poisson's ratio. Also the circular variation in thickness causes non uniformity in the shape of the plate. Bi linear temperature variation on the plate along both the axes is being viewed. The equation of motion related to frequency modes are solved by Rayleigh Ritz method. The findings of the present analysis are presented with the help of tables.
6
Content available Dynamic Test and Analysis of Strength of Bamboo Curtain Plywood Based on Free Vibration Modal Method
75%
Gu X. , Zhou A. , Adjei P. , Zhang R. , Zhou Y. , Wang Z.
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|
tom Vol. 66, nr 212
Art. no. 176766
EN
Bamboo curtain plywood is made of equal-thickness slotted bamboo slivers as its constituent units and is formed into boards with high pressure. In this paper, rectangular plates, beam specimens, and two sizes of square plates were tested to determine the elastic modulus and shear modulus of bamboo curtain plywood quickly, easily, and accurately. The free square board torsional vibration method was used to test the shear modulus of the square plates. The dynamic test results were also verified by means of the static four-point bending method. The main conclusions show that the dynamic elastic modulus, shear modulus and Poisson's ratio of this bamboo curtain plywood are 0.7 GPa, 1300 MPa and 0.12, respectively. The values of the elastic constants of these bamboo curtain plywood specimens measured by dynamic and static methods are consistent, and this dynamic test method has the advantages of fast, easy, good repeatability and high accuracy.
7
Determination of Poisson’s ratio by means of resonant column tests
75%
Sas W. , Gabrys K. , Szymanski A.
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|
nr 3
8
Content available Test for the auxetization of chosen polyurethane foams used in the production of seat bases for upholstered furniture
75%
Matwiej L. , Wiaderek K. , Jankowski K.
Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology
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2015
|
tom 92
9
On the existence and uniqueness of the relaxation spectrum of viscoelastic materials. Part I. The main theorem
63%
Stankiewicz A.
Teka Komisji Motoryzacji i Energetyki Rolnictwa
|
2010
|
tom 10
10
Content available Poisson’s ratio of anisotropic biological media
63%
Gladyszewska B.
Teka Komisji Motoryzacji i Energetyki Rolnictwa
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2012
|
tom 12
|
nr 2
11
Content available remote Symulacja numeryczna efektu "ujemnej temperatury" dla układu wirów punktowych
63%
Kudela H. , Regucki P.
Zeszyty Naukowe. Cieplne Maszyny Przepływowe - Turbomachinery / Politechnika Łódzka
|
2000
|
tom nr 117, vol. 2
143-148
PL
Przedstawiono badania numeryczne efektu "ujemnej temperatury" układu wirów punktowych w kwadracie ograniczonym ściankami sztywnymi. Do obliczeń wykorzystano metodę "cząstki wirowej w komórce"
EN
It was presented the "negative temperature" effect for the point vortex system in the square box with solid boundary. For the calculation it was used the "vortex -in-cell" method.
12
Badanie otwieralności opraw
63%
Stachowicz S.
|
|
tom R. 68, nr 7
418-424
PL
Parametr jakościowy oprawy, jakim jest jej otwieralność, w sensie fizycznym określa tendencja kart wkładu do układania się ich w otwartej oprawie w stosunku do poziomo położonych okładek. Określenie to w znacznym skrócie jest zdefiniowane w Polskiej Normie PN-82 P-55500 Introligatorstwo Przemysłowe. Terminologia.
EN
The article presents results of the research on quality of book-binding production and determination of a completely new paper parameter. The paper parameter helps to determine its usefulness for bookbinding purposes. The article also presents the method for the objective measurement of book binding openness with a two-point method. The final part of the article discusses the results of the tests of openness of otabind binding: homogenous full cloth and integrated, depending on the thickness of book bulk and its width and paper basis weight.
13
Identyfikacja parametrów sprężystego modelu podłoża gruntowego obciążonego udarowo
63%
Gosk W.
Zeszyty Naukowe. Budownictwo / Politechnika Śląska
|
2005
|
tom z. 104
115-122
PL
W pracy podjęto próbę identyfikacji parametrów odkształceniowych podłoża piaszczystego. Jako podstawę do analiz przyjęto badanie wykonane w warunkach laboratoryjnych z wykorzystaniem lekkiej płyty dynamicznej. Zarejestrowane wyniki poddano analizie w celu określenia wartości modułu odkształcenia i współczynnika Poissona. Prezentuje się wyniki z identyfikacji dokonanej z zastosowaniem modelu numerycznego podłoża w ujęciu falowym dla ośrodka liniowo sprężystego oraz modelu oscylatora.
EN
An attempt at identifying the deformation parameters of sandy ground it was made in the paper. The analysis basis was an experiment which was made in laboratory by the means of oscillator model. The recorded results were analyzed to determine values of deformation modulus and Poisson's ratio. For identification the numerical ground model and oscillator model were used. The numerical ground model was based on wave problem depiction for linear-elastic medium.
14
Content available remote Mechanical strength indicators of polyurethane adhesive in lightweight floor systems
63%
Karpiesiuk J.
Technical Transactions
|
2020
|
tom Vol. 117, iss. 1
art. no. e2020024
EN
The article describes the basic features of the lightweight floor system with heat-dissipating lamellas (LFS-L) that do not require screeds and are used in the design of radiant heating. It was assumed that reactive polyurethane adhesive constitute the connection layer between the ceramic tile floor and the thermal insulation substrate, which is covered with aluminium foil. This type of construction has not been fully tested for mechanical strength. To define it, for example, using the finite element method, strength indicators of the tested adhesives which were not used in any of the previous studies discussed in this paper should be determined, such as Young's modulus E, Poisson's ratio ν and linear thermal expansion coefficient α. This article presents research methods by which these data were determined. Module E and the ν ratio were determined in the compression strength test of cylindrical samples of polyurethane adhesive. Coefficient α was determined by using digital image correlation in the Aramis system, placing the prepared adhesive samples in a thermal chamber.
15
Content available Identyfikacja zmiennego w czasie współczynnika Poissona lepkosprężystych materiałów biologicznych na podstawie testu pełzania
63%
Stankiewicz A.
Inżynieria Rolnicza
|
2005
|
tom R. 9, nr 14
339--346
PL
W pracy, opierając się na całkowych równaniach konstytutywnych, wyprowadzono wzór określający zależność pomiędzy zmiennym w czasie współczynnikiem Poissona materiału liniowo lepkosprężystego a funkcjami pełzania w stanach jednoosiowego odkształcenia i jednoosiowego naprężenia. Opracowano algorytm identyfikacji zmiennego w czasie współczynnika Poissona na podstawie dyskretnych pomiarów jednoosiowych funkcji pełzania, uzyskanych eksperymentalnie dla próbki swobodnej i próbki ograniczonej w podwójnym teście pełzania.
EN
The need for knowledge of time-dependent viscoelastic material functions has been growing with the increased use of an accurate engineering methods for rigorous predictions of the plant materials behaviour, such as the finite element method (FEM) and the boundary element method (BEM). Essentially, only linear viscoelasticity is considered for which the correspondence principle applies. A new method for computing the time-dependent Poisson's ratio of linear viscoelastic materials, using discrete time-measurements of the uniaxial creep compliance of unconfined and a laterally constrained cylindrical specimens of the material obtained in double creep experiment, is developed on the basis of the constitutive convolution integral equations. The approach proposed solves the problem in Laplace transform domain and relies on numerical inversion for the determination for the time-dependent Poisson's ratio. The method combines effectiveness and accuracy and is general enough to cover both viscoelastic solids and liquids.
16
Eksperimental'nye issledovania fiziko-mehaniceskih svojstv sal'nikovyh nabivok
63%
Zagorul'ko A. , Gudkov C. , Gaft A.
|
2008
|
tom Z. 10, Vol. 2
115-121
EN
In the paper of experimental investigations of physicomechanical properties of packing are resulted.
17
Content available A comparison of mechanical parameters of tomato’s skin of greenhouse and soil-grown varieties
63%
Kuna-Broniowska I. , Gladyszewska B. , Ciupak A.
Teka Komisji Motoryzacji i Energetyki Rolnictwa
|
2011
|
tom 11C
EN
The paper presents the results of studies concerning the Young‘s modulus, critical stress, Poisson‘s ratio and thickness determined for the skin of greenhouse tomato cultivars (Admiro and Encore), and soilgrown varieties (Polset and Surya) comparison. Multivariate analysis of variance and one-dimensional tests [Hinkelmann 2008] were carried out. With the contrasts application the greenhouse varieties were compared with soil-grown ones. The comparison inside both: the greenhouse and soil-grown groups were also conducted. The homogeneity groups containing the average values of defined mechanical parameters of the tomato skin were determined.
PL
Praca zawiera wyniki badań dotyczących porównania wartości modułu Younga, naprężenia krytycznego, współczynnika Poissona i grubości skórki owoców pomidora szklarniowego odmian Admiro i Encore oraz gruntowego odmian Polset i Surya. W tym celu przeprowadzona została wielowymiarowa analiza wariancji oraz testy jednowymiarowe (Hinkelmann 2008). Za pomocą kontrastów porównano odmiany szklarniowe z odmianami gruntowymi, przeprowadzono również porównania wewnątrz odmian szklarniowych i gruntowych. Wyznaczono także grupy jednorodne średnich wartości badanych parametrów skórki owoców pomidora.
18
'Brocade' method for determination of the strain tensor elements of thin biological materials
63%
Gladyszewska B. , Szczurowska I. , Chocyk D.
Electronic Journal of Polish Agricultural Universities. Series Agricultural Engineering
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2007
|
tom 10
|
nr 1
19
Content available Deformation properties of sedimentary rocks in the process of underground coal gasification
63%
Bukowska M. , Sygała A.
|
|
tom Vol. 14, iss. 3
144--156
EN
The article presents results of research into changes in deformation properties of rocks, under influence of temperature, during the process of underground coal gasification. Samples of carboniferous sedimentary rocks (claystones and sandstones), collected in different areas of Upper Silesian Coal Basin (GZW), were heated at the temperature of between 100 and 1000-1200°C, and then subjected to uniaxial compression tests to obtain a full stress-strain curves of the samples and determine values of residual strain and Poisson's ratio. To compare the obtained values of deformation parameters of rocks, tested in dry-air state and after heating in a given range of temperature, normalised values of residual strain and Poisson's ratio were determined. Based on them, coefficient of influence of temperature on tested deformation parameters was determined. The obtained values of the coefficient can be applied in mining practice to forecast deformability of gangue during underground coal gasification, when in the direct surrounding of a georeactor there are claystones or sandstones. The obtained results were analysed based on classification of uniaxial compression strength of GZW gangue, which formed the basis for dividing claystones and sandstones into very low, low, medium and high uniaxial compression strength rocks. Based on the conducted tests it was concluded that the influence of uniaxial compression strength on the value of residual strain, unlike the influence of grain size of sandstones, is unambiguous within the range of changes in the parameter. Among claystones changes in the value of Poisson's ratio depending on their initial strength were observed. Sandstones of different grain size either increased or decreased the value of Poisson's ratio in comparison with the value determined at room temperature in dry-air conditions.
20
Content available remote Tribological properties of auxetic and conventional polypropylene weft knitted fabrics
63%
Uzun M. , Patel I.
|
|
tom Vol. 44, nr 2
120-125
EN
Purpose: The wear resistance and friction reducing properties of polymer fibres can be improved with negative Poisson's ratio behaviour. Poisson's ratio is defined as the ratio of transverse contraction strain to longitudinal extension strain in the direction of stretching force. Large number of materials have positive Poisson's ratio, however there are some materials which exhibit negative Poisson's ratio, they are termed auxetic materials. Auxetic materials present unique property that they expand in all directions when they are stretched and contract when compressed. This paper has highlighted, compared and discussed the variation between the modelling, theoretical and practical differences of auxetic materials wear behaviour. Design/methodology/approach: For the purpose of this work, auxetic and conventional fibres were produced by the melt spinning mechanism using extruder. The fibres physical properties were evaluated such as Poisson's ratio, fibre count, elongation, force and tenacity. Mono-filament fibres were used for fabrication of weft knitted fabrics; plain (1x1) structure was employed for knitting fabric. The wear resistance of the knitted fabrics were tested by using Nu-Martindale Abrasion and Pilling Tester and comparison were made. Findings: The abrasive wear test results demonstrated that the auxetic based weft knitted fabrics have superior wear behaviour than the conventional fibre based weft knitted fabrics. Practical implications: The experiment showed that the auxetic material is capable of sustaining large amount of abrasion compared to conventional fabric. Originality/value: The paper compare and discusse the variation between the modelling, theoretical and practical differences of auxetic materials wear behaviour.
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