Study on Damage Evolution and Fatigue Life of Corn Kernels

This research examines the microstructure, deformation and hysteresis curves of corn kernels with different water content, to quantify the quasi-brittle mechanical properties of corn kernels. A significant finding was that with the increasing water content from 10 to 30%, the maximum load that corn kernels can bear increases and then decreases gradually. The bearing capacity of corn grain with 14% moisture content was the highest. The limit load is 160 N. The relationship between load and fatigue life of corn kernel was obtained by a compressive fatigue test. The fatigue load–fatigue life curve of corn grains was established. It was concluded that the higher the load, the shorter the fatigue life, and with the increase in water content, the fatigue life of corn kernels would gradually decrease. This is because with the increase in water content, first, the linear elastic stage of corn grain gradually decreases, and the nonlinear stage gradually increases. The second is the transition from brittle fracture to quasi-brittle fracture, and the load required to produce damage inside the grain is gradually reduced. Through damage theory and Micro-CT test, the nonlinearity of damage accumulation in corn kernels was proved.