This paper’s goal was to select methods and a calibration procedure which would lead to the determination of relevant parameters of a discrete element method (DEM) and virtual material creation. Seven particulates were selected with respect to their shape (spherical and non-spherical), size and density. The first calibration experiment involved “packing test” to determine the shape accuracy and bulk density of virtual packed particulates. The series of simulations were compared with real experiments, and the size, shape and density of virtual particles were optimized. Using three apparatuses, the input parameter values were experimentally determined for a contact model that defines the behavior of particulates in DEM simulations. The research part of the paper examines the influence of factors such as particle number; pile formation method; and the method of evaluation of the angle of repose on the process of the calibration of virtual material. The most reproducible results were achieved by the “pilling” method and by the rotating drum—both evaluated by the geometric method. However, it is always advisable to make an overall visual comparison of the slope shape between the calibration simulation and the experimental curves. The bowl’s diameter to particle size ratio should be greater than 25, and the calibration experiment should contain approximately 4000 particles to ensure representative results during angle of repose calibration experiment.

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With the rise of additive technologies, the characterization of metal powders is increasingly required. There is a need to precisely match the properties of metal powders to a specific machine and to ensure highly consistent production. Therefore, the study aims at a detailed characterization of ten metal powders (Metal powder 316 L, Zn, Sn, Al, Cu, Mn, Fe, Bronze, Ti and Mo powder), for which the particle size distribution, morphology, static and dynamic angle of repose and the effective internal friction angle (AIFE) were determined. The AIFE parameter and flow index were determined from three commonly used rotary shear devices: The computer-controlled Ring Shear Tester RST-01. pc, the Brookfield PFT Powder Flow Tester and the FT4 Powder rheometer. The results showed that the values ​​for the device of one manufacturer did not fully correspond to the values ​​of another one. The flow characteristics of the metal powders were quantified from the particle size distribution data, static angle of repose, and AIFE data. According to the particle size distribution and angle of repose (AOR), 50% of the tested metal powders fell into the free-flowing mode. According to the evaluation of AIFE, 20% of the samples fell into the lower area. Based on the flow indexes calculated from the measurements of the shear devices used, 100% (RST-01.pc), 70% (PFT) and 50% (FT4) of the samples were included in the free-flowing category. When comparing the results, attention should be paid not only to the nature of the material, but also to the methodology and equipment used. A comparison of methodologies revealed similarities in the changing behavior of the different metal powders. A comparison of effective angles of AIFE and static AOR was shown, and a hypothesis of the conversion relation was derived.

To verify the effect of added starch on flowability and pelletization of spruce sawdust, were prepared mixtures with addition of 0, 5, 10, 15 and 20 % (w/w) starch. The measured basic mechanical-physical properties of the individual mixtures have shown that starch improves flowability of the mixture (growing value of the ffc parameter), reduces impact of friction forces on the contact stainless material (reduced wall friction), thus reducing energy demands of the process as regards flow of the mixture through the hopper of a pellet press. High-speed camera simulations, which evaluate the immediate speed of particles during discharge of the hopper, have proved that addition of a material with different distribution of size and shape of the particles (starch) has a favourable effect on the overall flowability of the mixture. When pelletizing a mixture with starch, which has a lower angle of internal friction, the pelletizing pressure in the die is slightly lower and the resulting pellets have a slightly lower density. This feature is compensated by prevailing positive effects of the added starch on the pelletization, where the resulting pellets have higher durability, higher hardness and moisture resistance.

The process of homogenization of particulates is an indispensable part of many industrial processes, and, therefore, it is necessary to pay a special attention to this area and develop it. This paper deals with a complex study of homogenization of particulate matters in a rotary drum in terms of shape, size, and density of particles. In addition, the influence of operating parameters, such as drum filling capacity, rotational speed, and drum filling pattern are also investigated. Studies of reproducibility of discrete element method simulations, effects of rotary drum sizes or effects of drum volumetric filling to the mixture homogeneity index were also carried out. In general, the least satisfactory values of the homogeneity index resulted from the mixing of particles with different densities. The dominating factor of homogenization was the drum filling-up degree. The course of the homogeneity index in 140, 280, and 420 mm drums was very similar and after five revolutions of the drum, identical values of the homogeneity index were achieved for all the drum diameters. The optimal drum filling-up degree is at 40–50% for the spherical particles and 30–40% for the sharp-edged particles. The repeatability of simulations showed the maximum relative standard deviation of the homogeneity index at 0.6% from ten simulation repetitions with the same parametric conditions.