Purpose
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.
Design/methodology/approach
Discrete element method based standard shear test simulations.
Findings
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.
Originality/value
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.
Purpose -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. Design/methodology/approach -Soil bin measurements and discrete element method (DEM)-based simulations. Findings -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. Research limitations/implications -Accurate calibration of discrete element model parameters can be done based on the reproduction of the whole Mohr-Coulomb failure line. Draught force ratiovelocity ratio values seem to be independent of tool geometry and soil conditions in case of velocity ratio higher than 2. Practical implications -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. Originality/value -The paper demonstrates that during the discrete element modelling of the soil-tool interaction, the tool vibration phenomenon should not be neglected.
Purpose -The purpose of this paper is to analyze the effect of screw angular velocity on the mixing efficiency of open mixing screws. Design/methodology/approach -Measurements and discrete element method (DEM)-based simulations.Findings -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. Research limitations/implications -By using DEM-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. Practical implications -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. Originality/value -The paper shows that by using discrete element-based simulations, the optimal working parameters of open mixing screws can be evaluated.
In the agricultural industry, the conservation of wheat grains in silos after stocking is a hard task. This is because when stocking a large crop, hot aeration from the bottom of the silo is not sufficient to preserve the crop and avoid losses due to the manifestation of moisture between grains and grains-wall. As a concern, engineers, as well as inspectors, challenged day-to-day issues whenever packing such granular material. A screw could be a good solution to improve the dryness of the particles and mix the bed material in case of stocking different types of grains. Mainly, the complexity does emanate from the model used to predict accurately the mixing performance. Emerging generation of simulation codes using the discrete element method (e.g., EDEM®, LIGGGHTS, etc.) have brought an intact solution to the problem of particulate flow and particles inhomogeneity. The present work has sought to develop predictive models for average mixing index and particles velocity distribution assessments in mixing of wheat granules in a small-scaled hopper base screw mixer. A screw-mated-horizontal-ploughs has been utilized to improve the agitation of grains rather than a simple screw. 1, 2 and 4 mated ploughs to the screw axle has been used, also the tilt angle of the 4 mated ploughs case has been varied as follows; 20°, 45° and 70° then evaluated. Next, findings regarding bed homogeneity are calculated using the Lacey method [1] for quantitative analysis and visual observations have been read out for qualitative assessment. Particles inhomogeneity is at its minimum when more ploughs mated to the screw were used.
PurposeTransportation 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.Design/methodology/approachThe possibility of using in situ modified vane shear test based measurement for the calibration of discrete element models is demonstrated in this work.FindingsThe advantage of employing the adjusted vane test is that the values of in situ measurements can be used for the calibration.Originality/valueThe procedure we present allows us to perform accurate discrete element calibration using data from on-site measurements that can be performed quickly and easily.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.