Authors

Abstract

In order to obtain the discrete element contact parameters of wet and viscous paddy field mud particles, an accurate numerical simulation model was constructed. Firstly,, the paddy field mud with an average particle size of 0.2 mm was taken as the research object, and the basic physical parameters and rheological behavior laws were obtained through physical measurements and rotational rheological tests. Based on the slump test, combined with the particle scaling theory and Johnson-Kendall-Roberts (JKR) model, and the slump and slump-flow values were taken as response values, the Plackett-Burman test, the steepest climb test and the Box-Behnken test were designed by Design-Expert software to complete the simulation parameters calibration. The optimal significance parameters are as follows: 0.096 J/m2 for the JKR surface energy of mud, 0.13 for the mud-mud restitution coefficient and 0.6 for the mud-steel static friction coefficient. Finally, the mud slump and fluidity verification tests showed that the relative errors between the simulation values and the physical values of slump and slump-flow are 1.73% and 0.42%, and the average error of torque is 2.47%, and the parameters are accurate and reliable. The calibration method can accurately construct the discrete element model of wet-viscous particles, which provides basic data and technical guidance for the coupling mechanism of paddy machinery-mud.

Abstract in Chinese

为获取湿黏性颗粒的离散元接触参数来构建精准的数值仿真模型，以水田泥浆为例。首先，以平均粒径为0.2 mm水田泥浆为研究对象，通过物理测定和旋转流变试验得出基本物理参数和流变行为规律。之后基于坍塌物理试验，结合颗粒缩放理论和JKR接触模型，以塌落度和拓展度为响应值，采用Design Expert 12软件依次设计Plackett-Burman试验、最陡爬坡试验和Box-Behnken试验完成仿真参数标定。这显著性参数最优值是泥浆 JKR 表面能为0.096 J/m2、泥浆-泥浆恢复系数为0.13和泥浆-钢静摩擦系数0.6。最后，水田泥浆塌落和流变验证试验表明，塌落度和拓展度仿真与物理值的相对误差为1.73%、0.42%，扭矩平均误差为2.47%，标定的参数准确可靠。本文提出的标定方法能构建精准湿黏性颗粒-泥浆离散元模型，为机械-泥浆耦合机理提供基础数据和技术指导。