Variations in the moisture content (MC) of grains strongly influence machine performance analysis during crop harvesting and post-harvest grain handling operations. For experimental or numerical methods such as discrete element method (DEM) technique to include the effect of MC on physical and mechanical properties, comprehensive study was conducted to investigate the effect of maize MC on single kernel properties and bulk grain dynamic responses, which have relevance for DEM crop model calibration. Individual kernel properties of shape, size, coefficient of restitution, and stiffness, and bulk material responses of bulk density, angle of repose, direct shear test (angle of internal friction, apparent cohesion), hopper flowability, and grain-machine interaction (GMI) impact plate forces responses were measured on maize samples at 11%, 16%, and 26% MC levels. At individual particle responses of coefficient of restitution and stiffness, maize kernels at MC of 26% had significantly the lowest values compared to the values at the other MC (11% and 16%). Increasing maize MC reduced the hopper discharge flowability by 20% and GMI impact plate forces by 25%. Significant effects of MC on the material behaviours should be considered for calibration of DEM maize models.

中文翻译：

---

谷物水分含量对玉米物理、机械和体积动态行为的影响

谷物水分含量 (MC) 的变化强烈影响作物收获和收获后谷物处理操作期间的机器性能分析。对于包括MC对物理力学性能影响的离散元法(DEM)技术等实验或数值方法，综合研究玉米MC对单粒特性和散粒动态响应的影响，具有相关性用于 DEM 作物模型校准。形状、尺寸、恢复系数和刚度的单个内核特性，以及松装密度、休止角、直剪试验（内摩擦角、表观内聚力）、料斗流动性和谷物-机器相互作用 (GMI) 的松散材料响应) 在 11%、16%、和 26% 的 MC 水平。在恢复系数和刚度的单个粒子响应中，MC 为 26% 的玉米粒与其他 MC 的值（11% 和 16%）相比具有显着最低的值。增加玉米 MC 使料斗卸料流动性降低 20%，GMI 冲击板力降低 25%。在校准 DEM 玉米模型时，应考虑 MC 对材料行为的显着影响。