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United States Department of Agriculture

Agricultural Research Service

Research Project: IMPROVED HANDLING AND STORAGE SYSTEMS FOR GRAIN QUALITY MAINTENANCE AND MEASUREMENT

Location: Engineering and Wind Erosion Research Unit

Title: Material and interaction properties of selected grains and oilseeds for modeling discrete particles

Authors
item Boac, Josephine -
item Casada, Mark
item Maghirang, Ronaldo -
item Harner, Iii, Joseph -

Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 1, 2010
Publication Date: July 1, 2010
Repository URL: http://naldc.nal.usda.gov/download/44454/PDF
Citation: Boac, J.M., Casada, M., Maghirang, R.G., Harner, III, J.P. 2010. Material and Interaction Properties of Selected Grains and Oilseeds for Modeling Discrete Particles. Transactions of the ASABE. 53(4):1201-1216.

Interpretive Summary: Physical characteristics are important in analyzing the behavior of grains in handling equipment. Experimental investigations of grain handling and commingling can be expensive and time-consuming, but computer simulations can reduce the large effort required to evaluate these handling operations. The relevant grain physical properties must be known to accurately simulate grain handling operations. This study was conducted to review the published physical properties of the major grains and oilseeds needed to model grain commingling with the discrete element method (DEM) and use these properties to develop and validate an appropriate particle model for one test seed, soybeans. A single-sphere particle model best simulated soybean kernels in tests of coefficient of restitution, angle of repose, and bulk density. The best particle model had coefficient of restitution of 0.6; static friction, 0.45 for soybean-soybean contact (0.30 for soybean-steel interaction); rolling friction, 0.05; normal particle size distribution with standard deviation factor of 0.4, and shear modulus, 1.04 MPa. The results of this study will be used for grain commingling simulation of major crops to accurately predict the impurity levels in the grain handling system, which can help farmers and grain handlers reduce costs during transport and export of grains and make U.S. grain more competitive in the world market.

Technical Abstract: Experimental investigations of grain flow can be expensive and time-consuming, but computer simulations can reduce the large effort required to evaluate the flow of grain in handling operations. Published data on material and interaction properties of selected grains and oilseeds relevant to Discrete Element Method (DEM) modeling were reviewed. Material properties include grain kernel shape, size and its distribution, Poisson’s ratio, shear modulus, and density. Interaction properties consist of coefficients of restitution, static friction, and rolling friction. Soybeans were selected as the test material for DEM simulations to validate the model fundamentals using material and interaction properties. Single- and multi-sphere soybean particle shapes, comprised of one to four overlapping spheres, were compared based on DEM simulations of fundamental parameters (i.e., coefficient of restitution, bulk density, and angle of repose). A single-sphere particle model best simulated soybean kernels in the fundamental parameter tests. The best particle model had coefficient of restitution of 0.6; static friction, 0.45 for soybean-soybean contact (0.30 for soybean-steel interaction); rolling friction, 0.05; normal particle size distribution with standard deviation factor of 0.4, and shear modulus, 1.04 MPa.

Last Modified: 8/27/2014
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