Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "granular materials" wg kryterium: Temat

  Lista filtrów
Wyrównaj
Wyświetlanie 1-15 z 20
Tytuł:
Evaluation of liquefaction potential for loose minefill slopes
Autorzy:
Kudella, P.
Powiązania:
https://bibliotekanauki.pl/articles/1954561.pdf
Data publikacji:
2022-02-07
Wydawca:
Politechnika Gdańska
Tematy:
liquefaction
granular materials
hypoplasticity
instability
failure
Opis:
Uncompacted embankments of certain fine sands exhibit a spontaneous liquefaction potential, which cannot be evaluated basing on undrained shear strength alone. A novel procedure for stability analysis has been developed, basing on Hill's stability criterion and a hypoplastic constitutive law. With given relative densities, assumed initial stress states and variations of perturbation directions, stability or instability of slope sections can be assessed. Catastrophic landslides observed in the past could thus be explained.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2000, 4, 3; 439-451
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Computational domain discretization for CFD analysis of flow in a granular packed bed
Autorzy:
Sosnowski, Marcin
Gnatowska, Renata
Sobczyk, Jacek
Wodziak, Waldemar
Powiązania:
https://bibliotekanauki.pl/articles/281600.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
granular materials
computational domain
discretization
CFD
Opis:
The paper reports results of an analysis concerning the infuence of a computational domain discretization method on the numerical stability of a model as well as the calculation error. The topology of a packed bed of a granular material consisting of granules contacting tangentially in one point makes the modeling of heat and mass transfer due to the fluid flow in such a domain a chalenging task. Therefore, the contribution of this paper constitutes a summary of discretization methods with discussion and guidelines allowing one to effectively select the most favourable method dedicated to discretization of the domain. The validation using Particle Image Velocimetry and evaluation of the impact of inflow velocity on the experimental and numerical research results are also presented in the paper.
Źródło:
Journal of Theoretical and Applied Mechanics; 2019, 57, 4; 833-842
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Introduction to hypoplasticity (GeoMath1)
Autorzy:
Kolymbas, D.
Powiązania:
https://bibliotekanauki.pl/articles/1954567.pdf
Data publikacji:
2000
Wydawca:
Politechnika Gdańska
Tematy:
granular materials
yield
hysteresis
dilatancy
constitutive equation
Opis:
Rational mechanics offers a tool to objectively describe the mechanical behaviour of granular materials by means of non-linear tensorial functions. This new framework is called hypoplasticity and is characterized by the simplicity of the mathematical formulations. The stress dependency of incremental stiffness, yield, loading-unloading hysteresis and dilatancy-contractancy are included. One of the features of hypoplasticity is that yield is a natural outcome of the theory and needs not be calibrated a priori. Also loss of uniqueness and localization of deformation are realistically predicted by hypoplasticity.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2000, 4, 3; 343-366
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A method for determining sieve holes blocking degree
Autorzy:
Lawinska, K. E.
Wodzinski, P.
Modrzewski, R.
Powiązania:
https://bibliotekanauki.pl/articles/110150.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
screen
sieving
screen blocking coefficient
granular materials
Opis:
The aim of this paper is to describe the process of sieve holes blocking. A series of tests and their results revealed a dependence describing the value of an average screen blocking coefficient as a function of two main factors affecting the process. These parameters are the toss indicator and the content of difficult-to-screen particles in the feed. The experiments presented in the paper showed that description in mathematical terms of the sieve holes blocking process is complex and difficult. A third degree polynomial function with two variables enables determination of the value of an average screen blocking coefficient in the processes of screening for specific arrangements: screen–particle–toss indicator–content of difficult-to-screen particles.
Źródło:
Physicochemical Problems of Mineral Processing; 2015, 51, 1; 15-22
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Concept of an adaptive-tuned particles impact damper
Autorzy:
Żurawski, Mateusz
Zalewski, Robert
Chiliński, Bogumił Daniel
Powiązania:
https://bibliotekanauki.pl/articles/2055066.pdf
Data publikacji:
2020
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
particles impact damper
adaptive-passive damping
smart materials
granular materials
Opis:
The most popular devices for attenuation of mechanical vibrations are dampers or shock absorbers. Two main energy dissipation strategies can be generally distinguished: passive and active (semi-active). Passive vibration isolation methods are the most commonly used, mainly because of their simplicity and low maintenance costs. Among passive vibration attenuation techniques, also Particle Impact Dampers (PID) are involved. Classical PID solutions have some certain limitations. This paper aims at presenting the new concept of an adaptive tuned PID damper that can pretend to be placed among semi-active energy dissipation methods.
Źródło:
Journal of Theoretical and Applied Mechanics; 2020, 58, 3; 811-816
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
FE-modelling of behaviour of granular anchors in rock and soils
Autorzy:
Wehr, J.
Tejchman, J.
Powiązania:
https://bibliotekanauki.pl/articles/1954551.pdf
Data publikacji:
2000
Wydawca:
Politechnika Gdańska
Tematy:
anchor
finite element method
granular materials
hypoplasticity
polar continuum
Opis:
The paper is concerned with granular anchors in rock and soils. Model tests and numerical calculations were performed. The effect of different parameters on the behaviour of anchors was investigated: anchor length, anchor diameter, initial density and mean grain diameter of the granular material, anchor roughness and stiffness of the borehole wall. The experiments were modelled with a finite element method and a polar hypoplastic constitutive relation. The relation can capture the salient properties of granular materials during shearing. A satisfactory agreement between experiments and numerical calculations was obtained. Advantages and limitations of granular anchors in rock and soils were outlined.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2000, 4, 3; 517-526
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The evolution of strain localisation in a hypoplastic cosserat material under shearing
Autorzy:
Bauer, E.
Huang, W.
Powiązania:
https://bibliotekanauki.pl/articles/1954558.pdf
Data publikacji:
2000
Wydawca:
Politechnika Gdańska
Tematy:
localisation
granular materials
polar effects
shearing
finite element method
Opis:
Numerical studies of the evolution of strain localisation and polar effects within a plane layer of a granular material under monotonic shearing are presented. Herein a micro-polar approach is formulated within the framework of a hypoplastic Cosserat continuum to describe the essential properties of a dry and cohesionless granular material like sand. The constitutive model is based on incremental non-linear tensor-valued functions and captures the influence of the pressure, the void ratio, the mean grain diameter and the rotation resistance of the grains on the evolution of the stresses and couple stresses. The Cosserat boundary conditions are suitable to model the rotation resistance at the interface between the granular layer and the surfaces adjoining the boundaries of the granular body. The numerical investigations show that the location, thickness and evolution of strain localisation within the shear layer are strongly influenced by the boundary conditions and the initial state quantities.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2000, 4, 3; 469-483
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling of the pressure and density sensitive behaviour of sand within the framework of hypoplasticity
Autorzy:
Bauer, E.
Powiązania:
https://bibliotekanauki.pl/articles/1954566.pdf
Data publikacji:
2000
Wydawca:
Politechnika Gdańska
Tematy:
hypoplasticity
element test
void ratio
critical state
granular materials
Opis:
In this paper a hypoplastic model proposed by Gudehus and Bauer is presented which is apt to describe the mechanical behaviour of loose and dense sand within a wide range of pressures and densities using a single set of constants. State changes are assumed to depend on the current void ratio, the Cauchy stress tensor and the stretching tensor. The constitutive equation is of the rate type and based on non-linear tensor-valued functions. By including a pressure dependent relative density the hypoplastic model describes the influence of pressure and density on the incremental stiffness, the peak friction angle and on the void ratio in a stationary state. The performance of the hypoplastic models is discussed and the results of numerical simulations are compared with experiments.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2000, 4, 3; 367-387
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of pressure evolution in granular materials in converging bins during filling and emptying processes
Autorzy:
Sielamowicz, I.
Mróz, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1955766.pdf
Data publikacji:
2003
Wydawca:
Politechnika Gdańska
Tematy:
granular materials
pressure
elastic and elasto-plastic model
filling
empting
Opis:
A simplified analysis of deformation and stress states in converging hoppers during filling and discharge of granular material is presented. In particular we discuss a method for solving the set of differential equations governing the flow of granular material in a plane wedge hopper. The equilibrium conditions and stress-strain relations are satisfied for the planar slice elements assuming the dependence of displacement and stress on the Cartesian coordinate z. The transient flow of an icompressible, cohesionless granular material in a two-dimensional converging hopper is considered. We assume the material to be in elastic or elasto-plastic states within the hopper satisfying the Coulomb yield condition and the non-associated flow rule. The paper presents a detailed analysis of the evolution of pressure acting on the hopper wall during the filling and emptying processes when the initial active state of pressure is transformed into a passive state. Analytical and numerical analyses are presented. It is shown that at the initial stage of the emptying process a considerable switch overpressure develops, exceeding the steady-state passive pressure several times.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2003, 7, 4; 643-666
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of the repose angle and porosity of granular plant materials on the angle of internal friction and cohesion
Wpływ kąta usypu i porowatości ziarnistych materiałów roślinnych na kąt tarcia wewnętrznego i kohezję
Autorzy:
Wójcik, A.
Frączek, J.
Powiązania:
https://bibliotekanauki.pl/articles/188616.pdf
Data publikacji:
2017
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
internal friction
porosity
granular materials
tarcie wewnętrzne
porowatość
materiały ziarniste
Opis:
Internal friction in granular plant materials is a very complex phenomenon. This is due to a vast number of factors that determine the behaviour of these materials. This article looks at exploring the impact of porosity, the repose angle, and moisture on the value of the internal friction angle and cohesion. Statistical analysis showed that the influence of the examined factors on the parameters of friction is statistically significant. Nonlinear estimation was performed, which allowed developing functions describing the mentioned relationship, for which the goodness-of-fit (depending on the material type) ranged from 0.813 to 0.915 for the internal friction angle and from 0.748 to 0.963 in the case of cohesion. It has been found that internal friction and cohesion need further research that will take into account additional factors defining the examined material in a more accurate manner.
Tarcie wewnętrzne roślinnych materiałów ziarnistych jest zjawiskiem bardzo złożonym. Wynika to z dużej ilości czynników determinujących zachowanie się tych materiałów. W artykule podjęto próbę określenia wpływu porowatości, kąta usypu oraz wilgotności na wartość kąta tarcia wewnętrznego i kohezję. Analiza statystyczna wykazała istotność wpływu badanych czynników na parametry tarcia. Przeprowadzono estymację nieliniową, która pozwoliła na zaproponowanie funkcji opisujących wspomnianą zależność, dla których uzyskano współczynnik dopasowania (w zależności od rodzaju materiału) od 0.813 do 0.915 dla kąta tarcia wewnętrznego oraz od 0.748 do 0.963 dla kohezji. Stwierdzono, że zarówno w przypadku kąta tarcia wewnętrznego, jak i kohezji należy prowadzić dalsze badania, uwzględniając dodatkowe czynniki, w sposób dokładniejszy charakteryzujące badany materiał.
Źródło:
Tribologia; 2017, 275, 5; 117-123
0208-7774
Pojawia się w:
Tribologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A comprehensive constitutive equation for granular materials
Autorzy:
Gudehus, G.
Powiązania:
https://bibliotekanauki.pl/articles/1954568.pdf
Data publikacji:
2000
Wydawca:
Politechnika Gdańska
Tematy:
constitutive equation of soil
critical state
deformation
granular materials
stability analysis
Opis:
constitutive equation is proposed for describing changes of states of granular materials, which are sufficiently characterised by the void ratio and the stress tensor. It may be considered as an extension of the Critical State concept. It is based on recently published hypoplastic equations and covers a wide range of densities, pressures and deformations. A factorial decomposition allows a rather easy separation and determination of material parameters. Two factors depend on a relative void ratio so that it remains within lower and upper bounds. The bounding void ratios decrease monotonously from maximal values to zero with increasing pressure. The same reduction of the void ratio is proposed for an isotropic compression starting from a suspension. Thus a granulate hardness is defined, and a stiffness factor can be determined. Four material parameters can be estimated from classification tests and determined from the asymptotic behaviour in element tests. Four further parameters are determined by calibration; they are rather constant for wide groups of materials. Strength and stiffness values can be derived and used for the analysis of deformations, stability, and flow. The viscous behaviour is modelled by a rate dependent factor with one further parameter. Limitations and possible extensions of this comprehensive approach are also outlined.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2000, 4, 3; 319-342
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigations of shear localization in granular bodies within an anisotropic micro-polar hypoplasticity
Autorzy:
Tejchman, J.
Powiązania:
https://bibliotekanauki.pl/articles/241368.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
bedding plane
granular materials
hypoplasticity
micropolar theory
shear zone
texturial anisotropy
Opis:
The paper focuses on the numerical analysis of the effect of texturial anisotropy on shear localization in cohesionless granular materials. For simulation of the mechanical behaviour of a granular material during a monotonous deformation path, a hypoplastic constitutive model was used. To take into account a characteristic length of micro-structure, the constitutive model was extended by micro-polar terms. To take into account texturial effects, the granular hardness was modified. The calculations were carried out with a sand specimen during plane strain compression under constant lateral pressure. A stochastic and uniform distribution of the initial void ratio in the granular specimen was assumed. In addition, shear localization for two different uniform initial void ratios was investigated.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2005, 52, 4; 351-371
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stochastic FE-analysis of shear localization in 2D granular material within a micro-polar hypoplasticity
Autorzy:
Tejchman, J.
Górski, J.
Powiązania:
https://bibliotekanauki.pl/articles/241120.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
granular materials
micro-polar hypoplasticity
shear localization
correlated random field
void ratio
Opis:
The paper deals with investigations of the effect of the stochastic distribution of the initial void ratio in granular bodies on shear localization during shearing of an infinite granular layer 500 mm high with free dilatancy under plane strain conditions. The initial void ratio was assumed to be stochastic with a correlated random field generated by a conditional rejection method by Walukiewicz et al (1997). To simulate mechanical behaviour of a cohesionless granular material during a monotonous deformation path, a micro-polar hypoplastic constitutive law was used, which takes into account particle rotations, curvatures, non-symmetric stresses, couple stresses and the mean grain diameter as a characteristic length. The proposed model captures the salient mechanical features of granular bodies in a wide range of densities and pressures with a single set of constants. In addition, the comparative FE-analyses were carried out with a uniform and spatially non-correlated random fields of the initial void ratio.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2006, 53, 4; 353-379
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evolution of shear localisation in earth pressure problems of a retaining wall
Autorzy:
Tejchman, J.
Powiązania:
https://bibliotekanauki.pl/articles/1986988.pdf
Data publikacji:
2002
Wydawca:
Politechnika Gdańska
Tematy:
earth pressure
granular materials
finite element method
hypoplasticity
polar continuum
retaining wall
shear localization
Opis:
The paper deals with numerical investigations of the evolution of shear localisation in granular bodies for earth pressure problems of a retaining wall in conditions of plane strain. The passive and active failure of a retaining wall in sand is discussed. The calculations are carried out with a rigid and very rough retaining wall undergoing horizontal translation, rotation around the top and rotation around the bottom. The behaviour of dry sand is numerically modelled with a finite element method using a hypoplastic constitutive relation within a polar (Cosserat) continuum. The constitutive relation is obtained through extension by polar quantities, viz. rotations, curvatures and couple stresses, using the mean grain diameter as a characteristic length. During FE-calculations, the attention is laid on the influence of different wall movements on shear localisation. In addition, the effects of the initial void ratio, distribution of the initial void ratio and mean grain diameter, pressure level and size of the sand body and retaining wall is investigated in the case of a passive wall translation. The FE-results are compared with corresponding experimental results of laboratory model tests.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2002, 6, 3; 387-410
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Using neural networks in the process of mixing heterogeneous granular materials
Wykorzystanie sieci neuronowych w procesie mieszania niejednorodnych materiałów ziarnistych
Autorzy:
Kolasa-Więcek, A.
Królczyk, J.
Powiązania:
https://bibliotekanauki.pl/articles/288695.pdf
Data publikacji:
2011
Wydawca:
Polskie Towarzystwo Inżynierii Rolniczej
Tematy:
materiał ziarnisty
mieszanie
mieszalnik bębnowy
sieć neuronowa
granular materials
mixing
drum mixer
neural networks
Opis:
The article presents an attempt based on experimental data to employ neural network for predicting intermixing ratios for loose materials in a drum mixer. Obtained predicted research results were compared to empirical data using the Pearson's test. Obtained correlation coefficient value is 96%, and proves good data matching.
W artykule na podstawie danych eksperymentalnych dokonano próby zastosowania sieci neuronowej do predykcji stopni zmieszania materiałów sypkich w mieszalniku bębnowym. Uzyskane prognozowane wyniki badań porównano z empirycznymi przy użyciu testu Pearsona. Wartość uzyskanego współczynnika korelacji wynosi 96% i świadczy o dobrym dopasowaniu danych.
Źródło:
Inżynieria Rolnicza; 2011, R. 15, nr 7, 7; 37-43
1429-7264
Pojawia się w:
Inżynieria Rolnicza
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 20

Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies