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The purpose of this study is the reduction of computational time demand of discrete element based modeling.

The methodology is the systematic changing of particle size and micromechanical parameters to reduce computational time requirements.

In some cases, the computational demand of discrete simulations can be reduced to about 95 per cent.

Based on the results and demonstrated methodology, the enormous computational time demand of discrete element-based modeling can be reduced significantly.

Transportation of the measurement samples from their original place to the measurement site causes significant changes in their mechanical properties. The possibility of making in situ measurements helps to create more precise discrete element models.

The possibility of using in situ modified vane shear test based measurement for the calibration of discrete element models is demonstrated in this work.

The advantage of employing the adjusted vane test is that the values of in situ measurements can be used for the calibration.

The procedure we present allows us to perform accurate discrete element calibration using data from on-site measurements that can be performed quickly and easily.

The effect of micromechanical parameters on the macromechanical behaviour of granular materials is analysed by using discrete element based model of the standard shear test.

Discrete element method based standard shear test simulations.

The approximate mathematical functions related to the effects of DEM micromechanical parameters density, Young-modulus, Poisson number, frictional angle, bond normal cohesion, bond tangential cohesion, rolling friction and particle shape on the macromechanical parameters of shear failure line (internal friction and cohesion) are determined by modelling large number of standard shear tests.

By knowing these effects of micromechanical parameters to the macromechanical behaviour of the simulated particle assembly, the calibration of discrete element models can be significantly accelerated.

The analysis of the effect of screw angular velocity on the mixing efficiency of open mixing screws.

Measurements and discrete element method based simulations.

There is an optimal screw rotation angular velocity above which there is no reason to operate the mixing apparatus, as the mixing efficiency does not increase with the increase of screw angular velocity.

By using discrete element method based optimization of open mixing screw apparatus, the effective mixing of agricultural grains can be achieved. The quality degradation of the dried product can be reduced.

The causeless increase of screw angular velocity results higher power consumption and quality degradation because of the increasing value of contact forces arising between the mixed particles.

Our article shows that by using discrete element based simulations, the optimal working parameters of open mixing screws can be evaluated.

The analysis of the effect of tool vibrations on the measured and simulated draught forces of cultivator tools. This paper aims to discuss this issue.

Soil bin measurements and discrete element method (DEM)-based simulations.

The soil-tool interaction induced free vibrations of cultivator tools have significant impact on the measured draught force, and the simulations made by using vibrating tools give similar results.

Accurate calibration of discrete element model parameters can be done based on the reproduction of the whole Mohr-Coulomb failure line. Draught force ratio – velocity ratio values seem to be independent of tool geometry and soil conditions in case of velocity ratio higher than 2.

DEM-based numerical simulations can be used for modeling the effect of tool vibration on the draught force values. During discrete element simulations of soil-tool interaction, the effect of tool vibration may not be neglected.

The paper demonstrates that during the discrete element modelling of the soil-tool interaction, the tool vibration phenomenon should not be neglected.