关键词: 农业工程, 应力裂纹, 热应力, 湿应力, 广义Maxwell模型

Abstract: In drying process of maize, the mechanism of crack generation was investigated, the distribution of thermo- and hydrostresses inside maize kernel were studied. Employing the general Maxwell model a stress model was proposed, which was then used to simulate the distributions of principal stress and shear stress inside the maize kernel. Simulation results show that both temperature gradient and moisture gradient significantly influence the magnitude and distribution of the stresses. Either principal stress or shear stress which exceeds the yield stress will result in cracking. Results also show that the maximal principal stress occurs inside the cutin endosperm, while the maximal shear stress occurs on the surface of the cutin endosperm.

Key words: agricultural engineering, stress cracks, thermostress, hydrostress, Maxwell model