Breakage behavior of corn kernels subjected to repeated loadings

Studying the breakage behavior of corn kernels subjected to repeated compressive events, including at low frequency and low strain rate, are important for the development of breakage models for prediction of kernel breakage in handling and processing machines. The main purpose of this study was to identify the breakage behavior and mechanism of weakening of corn kernels under repeated loadings as affected by their moisture content and kernel thickness. Corn kernels at four moisture content levels (8.20%, 11.95%, 16.00%, 20.02%) and in four thickness ranges were subjected to repeated compressive loading between two parallel steel plates in quasi-static regime at a constant loading rate of 2 mm/min (strain rates from 4.7 × 10−3 to 1.0 × 10−2). Conducted experiments allow to observe the different grain breakage patterns, identify the crack initiation and its development, describe the weakening of kernels by changes in the total specific energy, plastic and elastic deformation energies, and the number of loading cycles to break (breakage probability) the kernels. The results indicate that the breakage models describing the damage and weakening of grains in terms of changes in the total and strain energy or changes in the stiffness can be used for understanding the effect of moisture content and thickness on breakage of corn kernels.