Partner: Rimantas Kačianauskas

Vilnius Gedyminas Technical University (LT)

Recent publications
1.Marczewska I., Rojek J., Kačianauskas R., Investigation of the effective elastic parameters in the discrete element model of granular material by the triaxial compression test, ARCHIVES OF CIVIL AND MECHANICAL ENGINEERING, ISSN: 1644-9665, DOI: 10.1016/j.acme.2015.09.010, Vol.16, pp.64-75, 2016
Abstract:

The general objective of the present paper is to improve the understanding of micromechanical mechanisms in granular materials and their representation in numerical models. Results of numerical investigations on micro–macro relationships in the discrete element model of granular material are presented. The macroscopic response is analysed in a series of simulations of the triaxial compression test. The numerical studies are focused on the influence of microscopic parameters on the initial response. The effect of the contact stiffness and friction coefficient on the effective elastic moduli is investigated. Numerical results are compared with the analytical estimations based on the kinematic Voigt's hypothesis as well as with selected numerical results of other authors. The comparisons show that a better agreement between the numerical and analytical results is observed for particle assemblies with higher coordination numbers. Higher coordination numbers are related to more compact specimens and for a given specimen can be associated with low values of the contact stiffness and a higher confining pressure.

Keywords:

Discrete element method, Granular material, Triaxial test, Micro–macro relationship, Voigt hypothesis

Affiliations:
Marczewska I.-IPPT PAN
Rojek J.-IPPT PAN
Kačianauskas R.-Vilnius Gedyminas Technical University (LT)
2.Zabulionis D., Kačianauskas R., Rimša V., Rojek J., Pilkavičius S., Spring Method for modelling of particulate solid composed of spherical particles and weak matrix, ARCHIVES OF CIVIL AND MECHANICAL ENGINEERING, ISSN: 1644-9665, DOI: 10.1016/j.acme.2015.06.006, Vol.15, No.4, pp.775-785, 2015
Abstract:

In the present paper, a possibility of an approximation of elastic particulate composite with a network of elastic springs that undertake only axial forces is considered. It is assumed that the springs are equivalent to two hemispheres interacting through a weaker interface member. In a frame of the suggested approach, the description of the composite is limited to translational degrees of freedom, therefore, only a normal interaction between the spheres was considered. The methodology for calculation of the axial stiffness of the elastic springs and obtained solutions of the stiffness in explicit form are the main novelty of the article. A comparison of the stiffnesses of the springs obtained by the proposed methodology and by the three dimensional Finite Element Method (FEM) has shown a good agreement between them in a wide range of the ratio of the modulus of elasticity of the particles and matrix at four different distances between surfaces of the particles. A possibility of the approximation of particulate composite by springs was tested and discussed in details by comparing results of a mechanical response of a sample (under three different loading cases) modelled as a three dimensional solid and as a system comprised of the springs. The solutions were obtained by the FEM.

Keywords:

Spring network model, Lattice model, Particulate composites, Heterogeneous materials, Finite element modelling

Affiliations:
Zabulionis D.-Vilnius Gedyminas Technical University (LT)
Kačianauskas R.-Vilnius Gedyminas Technical University (LT)
Rimša V.-Vilnius Gedyminas Technical University (LT)
Rojek J.-IPPT PAN
Pilkavičius S.-Vilnius Gedyminas Technical University (LT)
3.Balevičius R., Sielamowicz I., Mróz Z., Kačianauskas R., Effect of rolling friction on wall pressure, discharge velocity and outflow of granular material from a flat-bottomed bin, PARTICUOLOGY, ISSN: 1674-2001, DOI: 10.1016/j.partic.2012.07.002, Vol.10, pp.672-682, 2012
Abstract:

The present paper provides both experimental and DEM analyses of the filling and discharge of pea grains from a 3D flat-bottomed bin. In the DEM model, the fixed mean values of the experimentally determined single particle data, such as the particle density, Young's modulus, Poisson's ratio as well as the sliding and rolling friction coefficients were incorporated to analyse their effects on the macroscale indicators, such as the wall pressure, discharge velocities and material outflow parameters. The effect of rolling friction was studied based on the experimentally measured single particle rolling friction coefficient. This analysis is aimed at the quantitative prediction of flow parameters as related to the identification of material parameters.

Keywords:

Visco-elastic granular material, Discrete element method, Rolling friction, Wall pressure, Material velocity, Outflow mass, Outflow rate, Biosystems, Pea grains

Affiliations:
Balevičius R.-Vilnius Gedyminas Technical University (LT)
Sielamowicz I.-University of Zielona Góra (PL)
Mróz Z.-IPPT PAN
Kačianauskas R.-Vilnius Gedyminas Technical University (LT)
4.Zabulionis D., Kačianauskas R., Markauskas D., Rojek J., Investigation of nonlinear tangential contact behaviour of a spherical particle under varying loading, BULLETIN OF THE POLISH ACADEMY OF SCIENCES: TECHNICAL SCIENCES, ISSN: 0239-7528, Vol.60, No.2, pp.265-278, 2012
5.Balevičius R., Sielamowicz I., Mróz Z., Kačianauskas R., Investigation of wall stress and outflow rate in a flat-bottomed bin: a comparison of the DEM model results with the experimental measurements, POWDER TECHNOLOGY, ISSN: 0032-5910, DOI: 10.1016/j.powtec.2011.08.042, Vol.214, pp.322-336, 2011
Abstract:

The present paper provides a discrete element method (DEM) analysis of the filling and discharge processes of granular material in a 3D flat-bottomed bin. A granular aggregate of nearly round particles (20,400 pea grains, 7.2–7.8 mm in diameter) is considered. The numerical results are compared with the experimental data. The DEM analysis provides an accurate prediction of wall stress distribution and the outflow rate of discharge throughout the bottom orifice. The stress distribution developed within the granular material after filling and during the discharge phase is considered, and the transition from the active to passive stress state is discussed. This analysis aims to quantitatively predict the flow parameters related to the careful identification of the material parameters. The investigation presented may be useful for the ongoing development of DEM.

Keywords:

Visco-elastic granular material, Discrete element method, Wall pressure, Granular material stress, Micro-properties, Bulk properties

Affiliations:
Balevičius R.-Vilnius Gedyminas Technical University (LT)
Sielamowicz I.-University of Zielona Góra (PL)
Mróz Z.-IPPT PAN
Kačianauskas R.-Vilnius Gedyminas Technical University (LT)
6.Balevičius R., Kačianauskas R., Mróz Z., Sielamowicz I., Analysis and DEM simulation of granular material flow patterns in hopper models of different shapes, ADVANCED POWDER TECHNOLOGY, ISSN: 0921-8831, DOI: 10.1016/j.apt.2010.12.005, Vol.22, pp.226-235, 2011
Abstract:

By using the discrete element method (DEM) a comparison and observations on material flow patterns in plane-wedged, space-wedged, and flat-bottomed hopper were accounted for. Numerical results obtained by combining data of individual particles, statistical processing of particle assemblies and evaluation of the field variables provided the essential characteristics for different regimes of the discharge flow (within steady or unsteady state of flow) and the differences in differently shaped hoppers due to different microscopic inter-particle friction. For validation of the performed simulations, velocity patterns developed in three-dimensional flat-bottomed hopper containing 20,400 pea grains were also analysed. To represent the continuum by avoiding the local effects produced by the individual grains, the simulation results were focused on the mean velocity distributions with data smoothening. The effect of rolling resistance on granular material flow was also considered.

Keywords:

DEM, Mass flow rate, Velocity distribution, Plane-wedged, Space-wedged, Flat-bottomed hoppers

Affiliations:
Balevičius R.-Vilnius Gedyminas Technical University (LT)
Kačianauskas R.-Vilnius Gedyminas Technical University (LT)
Mróz Z.-IPPT PAN
Sielamowicz I.-University of Zielona Góra (PL)
7.Balevičius R., Kačianauskas R., Mróz Z., Sielamowicz I., Discrete particle investigation of friction effect in filling and unsteady/steady discharge in three-dimensional wedge shaped hopper, POWDER TECHNOLOGY, ISSN: 0032-5910, DOI: 10.1016/j.powtec.2008.02.006, Vol.187, No.2, pp.159-174, 2008
Abstract:

The friction effect in filling and unsteady/steady discharge of three-dimensional wedge-shaped hopper was considered numerically by the discrete element method. The presented model is based on contact mechanics of a single spherical particle involving Hooke's law of spring interaction, static and dynamic friction as well as viscous damping forces. The hopper filling process en masse was performed while the modeling of uncontrolled and controlled discharge was simulated. The evolution of the kinetic energy of filling, the distribution of stresses within granular material and stresses acting on the walls, as well as the change in fields of material porosity were investigated at the stages of filling and discharge of the hopper. The variation of flow velocities, the discharged mass fractions as well as discharge fraction rates were analyzed. The friction effect was analyzed by varying inter-particle friction coefficient over the range of 0–0.6. A comparison of the numerical results with available continuum-based predictions was also presented.

Keywords:

Visco-elastic granular material, 3D wedge-shaped hopper, Discrete element method, Wall pressure, Granular stresses, Fraction discharged, Bulk porosity

Affiliations:
Balevičius R.-Vilnius Gedyminas Technical University (LT)
Kačianauskas R.-Vilnius Gedyminas Technical University (LT)
Mróz Z.-IPPT PAN
Sielamowicz I.-University of Zielona Góra (PL)
8.Balevičius R., Kačianauskas R., Mróz Z., Sielamowicz I., Microscopic and macroscopic analysis of granular material behaviour in 3D flat-bottomed hopper by the discrete element methody, ARCHIVES OF MECHANICS, ISSN: 0373-2029, Vol.59, pp.231-257, 2007
Abstract:

The paper presents the application of the discrete element method to modelling of granular material filling and discharge in 3D flat-bottomed hopper. A mathematical model, as well as the developed software code, operates with spherical visco-elastic non-cohesive frictional particles. The evolution of granular flow, internal forces and densification (rarefaction) are characterized by macroscopic parameters such as the discharge rates, the porosity fields and the wall pressures, as well as by microscopic evaluations in terms of coordination number, velocity patter ns and inter-particle contact forces. It was shown that qualitative characterization of flow may be done even by relatively rough models with small number of particles, which required to be increased, however, for more precise description of the localize d phenomena. Unsatisfactory evaluation of the stress peak during discharge is p resented as an illustrative example. The main focus of the paper is the analysis of particle friction effect and the consistency of micro and macro-phenomena in the time-dependent flow process.

Keywords:

discrete element method, spherical particles, visco-elastic granular material, three-dimensional flat bottomed hopper

Affiliations:
Balevičius R.-Vilnius Gedyminas Technical University (LT)
Kačianauskas R.-Vilnius Gedyminas Technical University (LT)
Mróz Z.-IPPT PAN
Sielamowicz I.-University of Zielona Góra (PL)
9.Balevičius R., Kačianauskas R., Mróz Z., Sielamowicz I., Discrete element method applied to multiobjective optimization of discharge flow parameters in hoppers, STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION, ISSN: 1615-147X, DOI: 10.1007/s00158-005-0596-z, Vol.31, pp.163-175, 2006
Abstract:

Multiobjective approach for optimization of the discharge flow parameters of viscoelastic frictional granular material in a wedge-shaped hopper with fixed outlet orifice is considered. The discharge time and the discharge flow rate are taken as optimality criteria, while the discharge mass of material and the shape of the hopper are considered as design variables. The discrete concept and numerical discrete element method (DEM) are applied to the analysis of granular flow. The filling problem considered as numerical generation of the initial conditions for discharge flow was initially solved. The presented DEM model was validated by examining the wall pressures and comparing them with the results of classical macroscopic pressure prediction. Variation of optimality criteria and Pareto set is demonstrated by the numerical results. Sensitivity of optimality criteria to interparticle friction is also investigated.

Keywords:

Viscoelastic granular material, Hopper, Discrete element method, Optimization of flow parameters

Affiliations:
Balevičius R.-Vilnius Gedyminas Technical University (LT)
Kačianauskas R.-Vilnius Gedyminas Technical University (LT)
Mróz Z.-IPPT PAN
Sielamowicz I.-University of Zielona Góra (PL)
10.Kačianauskas R., Mróz Z., Żarnovskij V., Stupak E., Three-dimensional correction of the stress intensity factor for plate with a notch, INTERNATIONAL JOURNAL OF FRACTURE, ISSN: 0376-9429, DOI: 10.1007/s10704-005-4401-1, Vol.136, pp.75-98, 2005
Abstract:

The 3D effects of the 2D mode I stress intensity factor for the plate with a V-shaped straight through-thickness notch are investigated by the finite element method and three-dimensional thicknessdependent correction of SIF is suggested. The correction relies on the assumed relationship between the SIF and the constraint factor (out-of-plane degree of freedom). The 3D finite element mesh generator combining the 2D in-plane adaptive unstructured mesh with the structured through-thickness mesh Is developed and applied for the analysis purposes. Three-dimensionality was examined by using two independent indicators, namely, stress- or strain-based constraint factors. The three-point bend and tensile center-cracked plates are investigated. The results demonstrated that the developed 3D corrections may be treated as upper bound estimates of the SIF for three-point bend plate,while directly obtained numerical values are considered as lower bound estimates. Analysis of the tensile center-cracked plate demonstrated a different nature of the 3D SIF profile, which cannot be simply explained as a transitional state between plain strain and plain stress. Therefore, the suggested 3D correction concept is of a particular character.

Keywords:

Constraint factor, finite element method, plate with a notch, three-dimensional stress intensity factor

Affiliations:
Kačianauskas R.-Vilnius Gedyminas Technical University (LT)
Mróz Z.-IPPT PAN
Żarnovskij V.-other affiliation
Stupak E.-other affiliation

Conference papers
1.Kačianauskas R., Rojek J., Pilkavičius S., Rimša V., Interaction of particles via solid interface: model and analysis − Particles 2013, Particles 2013, III International Conference on Particle-based Methods, 2013-09-18/09-20, Stuttgart (DE), pp.364-374, 2013
Abstract:

The paper addresses discrete element (DEM) models of the heterogeneous particulate solids where the normal interaction between two deformable spherical particles bonded via weaker solid interface is considered. The integral interaction model aimed for evaluation of the bond stiffness was developed, where analytical expressions of the stiffness parameters reflecting individual contribution of the two particles and of the interface properties are derived. Application of the developed DEM model to particulate solid with many particles is considered. The accuracy and the suitability of this approach are evaluated by considering refined 3D Finite Element analysis.

Keywords:

Heterogeneous Solid, Particles Interaction, DEM, FEM

Affiliations:
Kačianauskas R.-Vilnius Gedyminas Technical University (LT)
Rojek J.-IPPT PAN
Pilkavičius S.-Vilnius Gedyminas Technical University (LT)
Rimša V.-Vilnius Gedyminas Technical University (LT)

Conference abstracts
1.Marczewska I., Rojek J., Kačianauskas R., Investigation of micro-macro relationships of elastic parameters in the discrete element model of granular material, PCM-CMM 2015, 3rd Polish Congress of Mechanics and 21st Computer Methods in Mechanics, 2015-09-08/09-11, Gdańsk (PL), pp.91-92, 2015
Abstract:

A general objective of the paper is to improve understanding of micromechanical mechanisms in granular materials and their representation in numerical models. Results of numerical investigation on micro-macro relationship is the discrete element model of granular material are presented. The macroscopic response was analysed in a series of simulations of the triaxial compression test. Numerical studies were focused on the influence of microscopic parameters on the elastic response. The effect of the contact stiffness and the contact stiffness ratio on the effective elastic moduli, the Young’s modulus and Poisson’s ratio, were investigated. Numerical results were compared with the analytical estimations.

Keywords:

Discrete element method, granular material, triaxial test, micro-macro relationship, Voigt hypothesis, elastic moduli

Affiliations:
Marczewska I.-IPPT PAN
Rojek J.-IPPT PAN
Kačianauskas R.-Vilnius Gedyminas Technical University (LT)
2.Zabulionis D., Kačianauskas R., Rimša V., Rojek J., A model of stiffness of normal interaction of spherical particles embedded in matrix, PCM-CMM 2015, 3rd Polish Congress of Mechanics and 21st Computer Methods in Mechanics, 2015-09-08/09-11, Gdańsk (PL), pp.105-106, 2015
3.Kačianauskas R., Kačinskaja I., Maknickas A., Markauskas D., Rojek J., Simulation of attractive motion of silica microparticles in aerosol under acoustic excitation, PCM-CMM 2015, 3rd Polish Congress of Mechanics and 21st Computer Methods in Mechanics, 2015-09-08/09-11, Gdańsk (PL), pp.563-564, 2015
4.Marczewska I., Rojek J., Kačianauskas R., Micro-macro dependency for elastic constants in a numerical model of granular material, SolMech 2014, 39th Solid Mechanics Conference, 2014-09-01/09-05, Zakopane (PL), pp.175-176, 2014
5.Nosewicz Sz., Rojek J., Pietrzak K., Chmielewski M., Kaliński D., Kačianauskas R., Discrete Element Modelling of Solid State Sintering Process of Metal-Ceramic Composite, SolMech 2012, 38th Solid Mechanics Conference, 2012-08-27/08-31, Warszawa (PL), pp.172-173, 2012
6.Rimša V., Pilkavičius S., Kačianauskas R., Rojek J., Investigation of the Normal Contact Between Two Spherical Particles with Interface Material, SolMech 2012, 38th Solid Mechanics Conference, 2012-08-27/08-31, Warszawa (PL), pp.210-211, 2012