Drying stress analysis and cracking prediction of the component of maize based on viscoelastic stress-strain model

Abstract

To study the drying stress and predict cracking of the components of the maize kernel during drying, the viscoelastic stress-strain model of the maize kernel was developed considering the differences in viscoelastic properties of the components. The results showed that at the preheating and main drying stages, the stress was mainly caused by the uneven distribution of the moisture content and gradually increased with drying. At the cooling stage, the stress significantly increased in a short time due to the decrease in temperature. The stress of the hard endosperm was higher, the pericarp had the highest stress value, and the stress of the soft endosperm and germ was low. The crack volume percentage of the germ and pericarp was zero, which was consistent with the fact that there was no crack in the pericarp and germ, the cracks were mainly in the endosperm. The crack volume percentage of the endosperm gradually increased as drying progressed and significantly increased during the cooling stage, which was similar to the increasing trend in the crack degree of the endosperm at different drying stages. The viscoelastic stress-strain model combined with the von Mises stress criterion could be used to predict the stress crack formation of components at different drying stages.