ANALYSIS AND CALIBRATION OF PARAMETERS OF WET-VISCOUS PADDY MUD PARTICLES BASED ON THE SLUMP EXPERIMENT

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.