玉米干燥过程中颗粒内部应力分析与预测

Stress analysis and prediction of maize kernel during drying

通过对玉米干燥过程中应力裂纹产生机理的研究,分析了玉米在干燥过程中的热应力和湿应力,系统地分析了玉米颗粒内部应力的产生及分布状态,应用广义Maxwell模型建立了干燥过程中玉米颗粒内部应力模型;依据干燥应力模型,模拟了玉米颗粒内部各位置的径向应力和切向应力。结果表明:温度梯度和湿度梯度对内部应力影响显著,最大径向应力主要集中在角质胚乳中,最大切向应力主要集中在角质胚乳表面。

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.