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Wyszukujesz frazę "Tejchman, J" wg kryterium: Autor


Wyświetlanie 1-11 z 11
Tytuł:
FE-simulations of rapid silo flow with a polar elasto-plastic constitutive model
Autorzy:
Tejchman, J.
Powiązania:
https://bibliotekanauki.pl/articles/1953957.pdf
Data publikacji:
1998
Wydawca:
Politechnika Gdańska
Tematy:
finite element simulations
polar elasto-plastic constitutive model
silo flow
numerical modelling
model silo
convergent smooth walls
Opis:
The paper presents results on numerical modelling of rapid flow of granular materials in a model silo with convergent smooth walls. The calculations were performed with a finite element method based on a polar elasto-plastic constitutive relation by Muhlhaus (1995). The relation differs from the conventional theory of plasticity by the presence of Cosserat rotations and couple stresses using a mean grain diameter as a characteristic length. The characteristic length causes that numerical results do not depend upon the mesh discretisation. The model tests on rapid silo flow of glass beads performed by Renner in a glass hopper with a large wall inclination from the bottom were numerically simulated. The plane strain FE-calculations were performed by taking into account inertial forces and linear viscous damping. A satisfactory agreement between numerical and experimental results was obtained. Advantages and limitations of a continuum approach for simulations of rapid silo flow were outlined.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 1998, 2, 3; 473-501
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical studies on patterning of shear zone in granular bodies
Autorzy:
Tejchman, J.
Powiązania:
https://bibliotekanauki.pl/articles/1954556.pdf
Data publikacji:
2000
Wydawca:
Politechnika Gdańska
Tematy:
localisation
hypoplasticity
polar continuum
boundary conditions
shear zone
finite element method
Opis:
The paper deals with numerical investigations on the patterning of shear zones in granular bodies. The behaviour of dry sand during plane strain compression tests was numerically modelled with a finite element method using a hypoplastic constitutive relation within a polar (Cosserat) continuum. The constitutive relation was obtained through an extension of a non-polar one by polar quantities, viz. rotations, curvatures, couple stresses using the mean grain diameter as a characteristic length. This relation can reproduce the essential features of granular bodies during shear localisation. The material constants can be easily determined from element test results and can be estimated from granulometric properties. The attention is laid on the influence of boundary conditions and the distribution of imperfections in the granular specimen on the formation of patterns of shear zones.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2000, 4, 3; 485-516
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
FE studies of quasi-static mass flow in bins: the polar elasto-plastic approach
Autorzy:
Tejchman, J.
Powiązania:
https://bibliotekanauki.pl/articles/1955765.pdf
Data publikacji:
2003
Wydawca:
Politechnika Gdańska
Tematy:
elasto-plasticity
finite element method
flow
polar approach
silo
Opis:
The paper deals with numerical modelling of confined flow of granular materials in vertical bins. Quasi-static mass flow of non-cohesive sand with a controlled outlet velocity along the entire silo bottom was numerically studied using a finite element method taking into account an elasto-plastic constitutive law laid down within a Cosserat continuum. The influence of the initial density and the mean grain diameter of the solid, wall roughness, wall stiffness and imperfection, the initial stress state and the pressure level on the stress and deformation states in plane-strain vertical bins was investigated. The numerical results were compared with similar model tests performed with a rectangular vertical bin containing sand. The calculated results were in satisfactory agreement with the experimental ones. The advantages and limitations of the polar elasto-plastic approach to model granular silo flow were outlined.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2003, 7, 4; 667-699
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
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:
A Non-local elasto-plastic model to describe localisations of deformation in concrete
Autorzy:
Bobiński, J.
Tejchman, J.
Powiązania:
https://bibliotekanauki.pl/articles/1986935.pdf
Data publikacji:
2002
Wydawca:
Politechnika Gdańska
Tematy:
concrete
localisation
non-local theory
elasto-plasticity
characteristic length
Opis:
The paper presents numerical simulations of behaviour of concrete elements subjected to uniaxial compression for plane strain. FE-calculations are performed with two different elasto-plastic constitutive laws for concrete. Numerical results obtained suffer from mesh sensivity due to the presence of material softening. To obtain a well-posed boundary problem and a mesh independent solution, conventional constitutive laws with softening require an extension (called regularisation) to describe properly the localisations of deformations. In this paper elasto-plastic constitutive laws are extended by non-local strain terms. Owing to them, localisations of deformations are realistically captured.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2002, 6, 3; 437-446
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of a cellular automata model to granular flow
Autorzy:
Kozicki, J.
Tejchman, J.
Powiązania:
https://bibliotekanauki.pl/articles/1986936.pdf
Data publikacji:
2002
Wydawca:
Politechnika Gdańska
Tematy:
cellular automata
granular flow
silo
passive state
active state
Opis:
Paper presents the results of simulations of granular flow with a cellular automata model. Flow of granular material behind a moving retaining wall and in a silo with inserts was numerically analysed. Two different migration schemes during flow were assumed. Advantages and limits of the model were outlined.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2002, 6, 3; 429-436
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulations of flow patterns in silos with a cellular automaton: Part 2
Autorzy:
Kozicki, J.
Tejchman, J.
Powiązania:
https://bibliotekanauki.pl/articles/1965144.pdf
Data publikacji:
2005
Wydawca:
Politechnika Gdańska
Tematy:
cellular automation
collisions
density wave
granular flow
flow pattern
silo
Opis:
An improved cellular automaton has been used to calculate the kinematics of non-cohesive granular materials during confined flow in mass and funnel flow model silos. In this model, based on a gas model of hydrodynamics, collisions and dissipation of particles were taken into account during granular flow. The model allowed for investigations of dilatant zones in granular material during silo flow.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2005, 9, 1; 103-114
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulations of flow patterns in silos with a cellular automaton: Part 1
Autorzy:
Kozicki, J.
Tejchman, J.
Powiązania:
https://bibliotekanauki.pl/articles/1965146.pdf
Data publikacji:
2005
Wydawca:
Politechnika Gdańska
Tematy:
cellular automation
granular flow
flow pattern
insert
silo
Opis:
A simplified cellular automaton was used to calculate the kinematics of non-cohesive granular materials during confined flow in silos. In this model, granular flow was assumed to be an upward propagation of holes through a lattice composed of cells representing single particles. Calculations were carried out with different silo shapes and inserts, transition probabilities, migration rules, outflow schemes, grid types, wall roughness and cell numbers. To visualize the calculation process, horizontal layers of various shades were introduced. The simulation results were compared with laboratory tests in model silos.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2005, 9, 1; 81-102
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical analysis of behaviour of reinforced concrete elements under eccentric compression
Autorzy:
Majewski, T.
Tejchman, J.
Powiązania:
https://bibliotekanauki.pl/articles/1986991.pdf
Data publikacji:
2002
Wydawca:
Politechnika Gdańska
Tematy:
eccentric compression
concrete
finite element method
reinforced concrete
reinforcement
Opis:
Paper presents results of numerical modelling of behaviour of plane strain reinforced concrete elements under eccentric compression. In the analysis, a finite element method was used based on an elasto-plastic constitutive law by Drucker-Prager with hardening and softening for concrete and an elasto-plastic constitutive law by von Mises for reinforcement. The effects of boundary conditions at the element ends, eccentricity of the compressive load, element slenderness, area of the longitudinal and horizontal reinforcement on the load bearing capacity of elements were studied. The effect of the mesh refinement on the bearing capacity of elements was also analysed. A satisfactory agreement with model tests was achieved.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2002, 6, 3; 411-428
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
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:
Experimental and theoretical studies of resonance effects during confined flow in silos
Autorzy:
Niedostatkiewicz, M.
Tejchman, J.
Powiązania:
https://bibliotekanauki.pl/articles/1955770.pdf
Data publikacji:
2003
Wydawca:
Politechnika Gdańska
Tematy:
bulk solid
cohesion
dynamic effects
finite element method
model tests
polar elastoplasticity
resonance
silos
Opis:
The paper deals with experimental and theoretical research of resonance effects during silo emptying. The influence of resonance effects on wall pressures in silos has been investigated with model tests and FE analyses. The model tests were carried out with a cylindrical and rectangular silo containing various cohesive and non-cohesive bulk solids. The onset of dynamic silo flow was simulated with controlled outlet velocity along the bottom in a plane strain model and large silo. The confined flow of dry sand in a silo with parallel walls during resonance was described with a finite element method based on a polar elasto-plastic constitutive law. It differs from the conventional theory of plasticity by the presence of Cosserat rotations and couple stresses using mean grain diameter as a characteristic length. In the FE calculations, the silo walls were taken into account.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2003, 7, 4; 595-610
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-11 z 11

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