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    Wyświetlanie 1-13 z 13
    Tytuł:
    A Non-local hypoplastic constitutive law to describe shear localisation in granular bodies
    Autorzy:
    Tejchman, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/240962.pdf
    Data publikacji:
    2003
    Wydawca:
    Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
    Tematy:
    characteristic length
    finite element method
    non-local model
    plane strain compression
    shear localization
    Opis:
    The paper presents a FE-analysis of shear localisation in granular bodies by a finite element method based on a hypoplastic constitutive law. The law can reproduce essential features of granular bodies depending on the void ratio, pressure level and deformation direction. To realistically simulate the formation of a spontaneous shear zone inside cohesionless sand during plane strain compression, a hypoplastic constitutive law was extended by non-local terms. The effects of initial void ratio, pressure level and a characteristic length on the thickness of an interior shear zone were shown. The numerical results were compared with corresponding laboratory tests.
    Źródło:
    Archives of Hydro-Engineering and Environmental Mechanics; 2003, 50, 4; 359-379
    1231-3726
    Pojawia się w:
    Archives of Hydro-Engineering and Environmental Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Simulation of shear localization in granular bodies within gradient-enhanced hypoplasticity
    Autorzy:
    Tejchman, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/241309.pdf
    Data publikacji:
    2004
    Wydawca:
    Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
    Tematy:
    characteristic length
    finite element method
    gradient model
    plane strain compression
    shear localization
    Opis:
    The paper presents a FE-analysis of a spontaneous shear localization inside non-cohesive sand during plane strain compression. The calculations were carried out with a gradient-enhanced hypoplastic constitutive law. The hypoplastic law can reproduce essential features of granular bodies depending on the void ratio, pressure level and deformation direction. To model the thickness of shear zones, a characteristic length of the microstructure was incorporated via the second gradient of the modulus of the deformation rate. To determine the effect of micro-structure, the analysis was performed with different characteristic lengths for the same specimen size.
    Źródło:
    Archives of Hydro-Engineering and Environmental Mechanics; 2004, 51, 3; 243-265
    1231-3726
    Pojawia się w:
    Archives of Hydro-Engineering and Environmental Mechanics
    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:
    Fe-analysis of patterning of shear zones in granular bodies for earth pressure problems of a retaining wall
    Autorzy:
    Tejchman, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/241166.pdf
    Data publikacji:
    2004
    Wydawca:
    Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
    Tematy:
    earth pressure
    granular materials
    finite element method
    hypoplasticity
    polar continuum
    retaining wall
    shear localization
    Opis:
    The evolution of shear zones in granular bodies for earth pressure problems of a retaining wall in conditions of plane strain was analyzed. The passive and active failure of a retaining wall was discussed. The calculations were 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 was numerically modelled with a finite element method using a hypoplastic constitutive relation with polar extensions. Attention was paid to the influence of different wall movements on shear localization. The initial void ratio was assumed to be non-uniformly distributed. The geometry of calculated shear zones was compared with corresponding experimental results of laboratory model tests.
    Źródło:
    Archives of Hydro-Engineering and Environmental Mechanics; 2004, 51, 4; 317-348
    1231-3726
    Pojawia się w:
    Archives of Hydro-Engineering and Environmental Mechanics
    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
    Tytuł:
    Numerical mesoscopic analysis of fracture in fine-grained concrete
    Autorzy:
    Skarżyński, Ł.
    Tejchman, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/230197.pdf
    Data publikacji:
    2012
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    kruszywo
    beton
    metoda elementów skończonych
    strefa przejściowa międzyfazowa
    mikrostruktura
    aggregate
    concrete
    finite element method
    interfacial transition zone
    microstructure
    Opis:
    This paper presents numerical two-dimensional results for fine-grained concrete under quasi-static three-point bending at meso-scale. Concrete was modelled as a random heterogeneous three-phase material. The simulations for notched concrete beams were carried out with the standard finite element method using an isotropic damage constitutive model enhanced by a characteristic length of micro-structure by means of a non-local theory. The effect of the volume fraction, shape, size, statistical distribution and stiffness of aggregate was analysed. Moreover, the effect of the bond thickness, notch size and characteristic length of micro-structure on the material behaviour was numerically investigated. The FE results were compared with own laboratory test results and other meso-scale calculations for three-phase concrete elements.
    Źródło:
    Archives of Civil Engineering; 2012, 58, 3; 331-361
    1230-2945
    Pojawia się w:
    Archives of Civil Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A two-scale numerical approach to granular systems
    Dwuskalowe numeryczne podejście do systemów granulowanych
    Autorzy:
    Nitka, M.
    Tejchman, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/231189.pdf
    Data publikacji:
    2011
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    metoda elementów dyskretnych
    metoda elementów skończonych
    materiał granulowany
    technika homogenizacyjna
    podejście dwuskalowe
    discrete element method
    finite element method
    granular material
    homogenization technique
    two-scale approach
    Opis:
    A two-scale numerical homogenization approach was used for granular materials. At small-scale level, granular micro-structure was simulated using the discrete element method. At macroscopic level, the finite element method was applied. An up-scaling technique took into account a discrete model at each Gauss integration point of the FEM mesh to derive numerically an overall constitutive response of the material. In this process, a tangent operator was generated with the stress increment corresponding to the given strain increment at the Gauss point. In order to detect a loss of the solution uniqueness, a determinant of the acoustic tensor associated with the tangent operator was calculated. Some elementary geotechnical tests were numerically calculated using a combined DEM-FEM technique.
    Zastosowano dwuskalowe numeryczne podejście homogenizacyjne do materiałów granulowanych. Na poziomie małej skali symulowano granulowaną mikrostrukturę przy zastosowaniu metody elementów dyskretnych. Na poziome dużej skali zastosowano metodę elementów skończonych. Technika przechodzenia do wyższej skali uwzględniła dyskretny model w każdym punkcie całkowania Gaussa siatki MES w celu wyprowadzenia numerycznego obliczenia wynikowej konstytutywnej odpowiedzi materiału. W tym procesie, operator styczny został obliczony za pomocą przyrostu naprężenia odpowiadającego danemu przyrostowi odkształcenia w punkcie Gaussa. W celu wykrycia utraty jednoznaczności rozwiązania, określono wyznacznik tensor akustycznego związanego z operatorem stycznym. Obliczono numerycznie kilka podstawowych testów geotechnicznych stosując połączoną technikę MED-MES.
    Źródło:
    Archives of Civil Engineering; 2011, 57, 3; 313-330
    1230-2945
    Pojawia się w:
    Archives of Civil Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Modelowanie jednoosiowego rozciągania i ściskania betonu na poziomie kruszywa
    Modeling single axis stretching and compressing in case of the aggregated concrete
    Autorzy:
    Suchorzewski, J.
    Nitka, M.
    Tejchman, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/160601.pdf
    Data publikacji:
    2015
    Wydawca:
    Polski Związek Inżynierów i Techników Budownictwa
    Tematy:
    beton
    rozciąganie jednoosiowe
    ściskanie jednoosiowe
    pękanie
    modelowanie
    metoda elementów skończonych
    MES
    concrete
    uniaxial tension
    uniaxial compression
    cracking
    modelling
    finite element method
    FEM
    Opis:
    Artykuł przedstawia wyniki modelowania betonu na poziomie kruszywa podczas ściskania i rozciągania jednoosiowego za pomocą metody elementów dyskretnych. Beton opisany został jako materiał 4-fazowy złożony z kruszywa, zaprawy cementowej, makroskopowych porów oraz stref przejściowych między kruszywem a zaprawą. Obliczenia dwuwymiarowe wykonano dla próbki kwadratowej 10×10 cm2 (ściskanie) oraz w kształcie kości psa 10×15 cm2 z przewężeniem w środku równym 6 cm (rozciąganie). Wyniki numeryczne porównano bezpośrednio z wynikami doświadczalnymi. Krzywe naprężenie-odkształcenie w obliczeniach numerycznych były podobne jak krzywe doświadczalne.
    The article presents the results of modeling process pertaining the crushed concrete material during compression and stretching in a single axis, with the use of the discrete elements method. Concrete is described as a 4-phase material consisting of aggregate, cement mortar, macroscopic pores and transition zones, between the crushed aggregate and the mortar. The two-dimensional calculations have been carried out for two square samples (10x10 sq. cm – compression) and in case of a bone-shaped sample, with dimensions of 10 x 15 sq cm, with a 6 cm narrow part in the middle (stretching). Numerical data was directly compared with the experimental results. The functions between deformation and stress, in the numerical calculations, matched the experiment results.
    Źródło:
    Przegląd Budowlany; 2015, R. 86, nr 11, 11; 22-25
    0033-2038
    Pojawia się w:
    Przegląd Budowlany
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Experiments and FE Analyses on Airborne Sound Properties of Composite Structural Insulated Panels
    Autorzy:
    Wawrzynowicz, A.
    Krzaczek, M.
    Tejchman, J
    Powiązania:
    https://bibliotekanauki.pl/articles/177722.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    acoustic properties
    composite structural insulated panel
    sound insulation
    finite element method
    steady state analysis
    transient analysis
    Opis:
    Airborne acoustic properties of composite structural insulated panels CSIPs composed of fibre- magnesium-cement facesheets and expanded polystyrene core were studied. The sound reduction ratings were measured experimentally in an acoustic test laboratory composed of two reverberation chambers. The numerical finite element (FEM) model of an acoustic laboratory available in ABAQUS was used and verified with experimental results. Steady-state and transient FE analyses were performed. The 2D and 3D modelling FE results were compared. Different panel core modifications were numerically tested in order to improve the airborne sound insulation of CSIPs.
    Źródło:
    Archives of Acoustics; 2014, 39, 3; 351-364
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-13 z 13

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