Measured damage resistance of corn and wheat kernels to compression, friction, and repeated impacts

The damage resistance of grain kernels to external loading is useful for optimizing agricultural equipment design and adjusting operational settings. This study aims to quantify and compare the damage resistance of corn and wheat kernels under different types of loading and fit the data with statistical models. The damage resistance of corn and wheat kernels to compression, friction, and repeated impacts was measured using a universal testing machine, pin-on-disk tribometer, and Wisconsin breakage tester/rotary blade impactor, respectively. The average fracture force and fracture energy under compression ( +/- one standard deviation) were, respectively, 309A +/- 107.1 N and 48.7 +/- 27.1 mJ for corn, and 83.4 +/- 23.8 N and 28.7 +/- 13.5 mJ for wheat. The wear damage was insignificant for corn-acrylic, corn-steel, and wheat-acrylic wear tests. For the wheat-steel wear test, the average work done by the friction force to cause pericarp damage was 3.85=1.50 J. A lognormal distribution was used to fit the compression test data, and a three-parameter Weibull distribution was used to fit the repeated impact test data. The statistical models fit the damage probability based on the loading force or input energy with R-squared values over 0.98. It was found that corn and wheat kernels were susceptible to compression and impact loading, while both had high resistance to wear damage. (C) 2020 Elsevier B.V. All rights reserved.