Granular mechanics formulary for soft red winter wheat in corrugated storage bins

Much of the work in the area of grain storage bin design has been accomplished on smaller scale models with the results extrapolated to larger on-farm or commercial storage structures. This is a common methodology, however, several factors including kernel size, corrugation geometry, material density, and frictional characteristics among others, do not allow the requirements of precise similitude to be met. This investigation determined the influence of scale on several phenomena present in tall, slender, corrugated steel storage bins and developed relationships to predict their occurrence. Scale factors have been determined to characterize wear-in in new bins, the occurrence of the switch phenomenon which describes instantaneous peak wall loads encountered at the initiation of unloading, and perhaps most importantly, the effect of bin size on the occurrence flow regimes. Other phenomena including phase reversal and curl progression over the surcharge were also investigated.; The magnitude of the loads imposed on the thin cylindrical bin shell in terms of vertical pressure on the walls and floors and circumferential pressure on the walls is of special importance in the design and manufacture of grain storage bins. Designers have relied on various forms of the classical Janssen prediction equation and applied different modifiers to try to account for the tendency of the method to under-predict these pressures. This analysis developed a new and mathematically more rigorous solution to the differential form of Janssen's equation based in first principles which takes into account variable material properties prior to integration of the solution. This solution was transformed to an expression based on dimensionless terms referred to as the Improved Janssen Ratio or IJR Equation, and used to evaluate the experimental observations. A computer model was generated to fit this expression to data collected from four test bins ranging in diameter from 0.61 m to 2.44m and filled with soft red winter wheat to six different height to diameter (H/D) ratios ranging from 0.50 to 2.75. Relationships were developed for calculation of model coefficients used to predict dimensionless wall load ratio (wall load to total load, WLR) for bins of varying diameters. Comparisons were made between the model and existing prediction methodologies to demonstrate adaptability and compatibility of the method.