Friction Coefficients for Dried Distillers Grains on Eight Structural Surfaces

Abstract

<p>Static and dynamic coefficients of friction on structural surfaces play important roles in the power requirements and material selection for equipment used in handling and storing agricultural commodities. However, friction data on dried distillers grains with solubles (DDGS) is limited. Further, lack of a standardized method for determining friction coefficient on grain handling materials presents a challenge. This article describes studies carried out to determine the static coefficient of friction (µs) and dynamic coefficient of friction (µd) for corn DDGS at 10%, 8.2%, and 6.5% moisture content (all moistures are % wet basis) on eight structural surfaces: High-Density Polyethylene (HDPE), Ultra-High Molecular Weight Polyethylene (UHMWPE), 20-gage aluminum, galvanized steel, mild steel, 18-gage stainless steel, poplar wood, and pine wood. For all structural surfaces and DDGS moistures tested, µs lies in the range from 0.20 to 0.43 and µd in the range from 0.17 to 0.35. The µs values were higher than corresponding µd values for all moisture levels. In general, µs and µd increased linearly with increasing moisture for metal and wood surfaces. Pine wood had the highest µs at all moisture levels and the highest µd at 8.2% and 10% moisture. HDPE had the lowest µs and µd at 10% moisture followed by the values for UHMWPE. For these surfaces the µs and µd remained the same or decreased with increasing DDGS moisture. Among the metal surfaces, galvanized steel and aluminum exhibited similar coefficient of friction characteristics however galvanized steel had the lowest µs and µd at 6.5% and 8.2% moisture.</p>