Authors

Abstract

Rice buds are easily bruised or broken during sowing, which affects the seedling rate, and the discrete element simulation of rice buds lacks an accurate model in this process. The EDEM simulation software was used to calibrate the parameters of the discrete element simulation model for different states of rice bud seeds damage. The Hertz-Mindlin model was used to simulate the accumulation of rice bud seeds. Through a series of tests, the interspecific static friction factor was 0.644, and the rolling friction factor was 0.062. The normal contact stiffness and tangential contact stiffness were determined for the broken chest state and the 1-3 mm shoot length state, respectively, by using the meta-particle function to build rice seed sprouts and applying the bonding model to conduct Box - Behnken response surface tests for shear damage of rice seed sprouts. Finally, experiments were carried out with a hole-belt-type seed meter. The results showed that under different belt speeds, the relative error between the measured value and the simulated value of the rice bud damage rate was not more than 0.9%, indicating that the calibration parameters were accurate and reliable.

Abstract in Chinese

水稻在播种过程中种芽易被碰伤或折断影响成苗率，且此水稻种芽离散元仿真缺乏准确模型。以不同状态水稻芽种为研究对象，利用 EDEM 仿真软件开展水稻种芽损伤离散元仿真模型参数标定研究。应用Hertz - Mindlin 模型进行水稻芽种堆积仿真试验，通过一系列试验，确定了水稻芽种颗粒种间静摩擦因数为0.644，种间滚动摩擦因数为0.062。利用 meta-particle功能建立水稻芽种并应用Hertz - Mindlin with bonding 粘结模型开展水稻种芽剪切破坏离散元单因素和Box - Behnken响应曲面试验，确定了破胸状态与芽长1-3mm状态时法向接触刚度分别为1.07×10e+08N/m、8.99×10e+07N/m，切向接触刚度分别为9.05×10e+07Pa、8.24×10e+07Pa。采用型孔带式排种器进行了试验验证，结果表明，在不同带速条件下，水稻种芽损伤率实测值与仿真值的相对误差不大于0.9%，说明标定参数准确可靠。