WEAR-IN EFFECTS ON LOADS AND FLOW IN A CONICAL GRAIN BIN

The vertical wall and floor loads exerted by soft red winter wheat in a flat floor; conical-shaped model grain bin were determined as a func tion of the number of fill and unload cycles (Loading Cycles - LCs). T he bin was 7.3 m high with a base diameter of 2.44 m. The angle of the wall inclination with respect to horizontal was equal to 84 degrees. The conical wall of the bin and the flat floor were each supported ind ependently on three load cells to isolate wall and floor loads. The bi n was centrally filled from a spout and centrally discharged. Repeated LCs in the test bin decreased the coefficient of wall friction. As a consequence, the ratio of vertical wall load-to-total grain load, the dynamic-to-static wall load ratio, and the height to diameter ratio at which flow changed from plug to funnel varied with the increase in th e number of LCs. Oscillation of wall and floor loads resulting from st ick-slip friction were observed during the first seven LCs. An increas e in the absolute value of the negative wall load (uplifting force) wa s observed as the number of LCs increased.