Performance of elastic ball screen-cleaning device based on DEM-MBD coupling simulation

In seed breeding, the vibrating screen used for pre-sowing grading parental seeds often has the problem of poor self-purification rate. Using elastic balls to clean the plugging seeds and ensure the self-purification of the screen is a viable technical solution. To clarify and improve the operating performance of the elastic ball particles, a DEM-MBD coupling simulation model of the elastic ball screen-cleaning device was established in this study, and a numerical simulation analysis of the complex motion process was carried out. The mechanism of action of the elastic ball was explained more completely from the aspects of excitation force and energy transfer. Through the Plackett-Burman test, it was determined that the vibration frequency has the most significant effect on the excitation force. Multiple linear regression analysis was performed on each factor and the mathematical relationship equation. It was found that when the maximum excitation force was greater than 7 N and the average excitation force was greater than 2 N, the self-purification rate was greater than 95%. The self-purification rate was then increased to 99.81% by variable frequency tests. The variable frequency achieved better self-purification effect.

Discrete element simulations and experiments of soil-winged subsoiler interaction

Understanding soil disturbance behaviors under the impact of the winged subsoiler is critical for designing or optimizing the winged subsoiler(a primary subsoiling tool).In this study,a soil-winged subsoiler interaction model was developed and the effects of winged subsoiler on soil disturbance behaviors were investigated using the discrete element method(DEM)simulations and lab soil-bin tests.The results showed that wings mainly affected the disturbance range and fragmentation degree of soil above them.The draught forces of share section(SS),arc section in the hardpan(ASHP),arc section in the top layer(ASTL)and line section(LS)were accounted for 69.53%,25.22%,4.73%and 0.52%of the total draught force of winged subsoiler;the lateral disturbance range from high to low of the soil at different depths followed the ranking:top layer(TL),hardpan disturbed by arc section(HDAS)and hardpan disturbed by share section(HDSS).Wings had the greatest influence on the draught force of ASHP.Adding wings to an arc-shaped subsoiler increased the disturbance areas of HDAS,TL and HDSS by 47.52%,7.74%and 4.59%,respectively,but meanwhile increased the total draught force by 36%.Compared with a non-winged subsoiler,winged subsoiler had higher soil looseness(15.83%),soil disturbance coefficient(58.59%),furrow width(448.65 mm)and soil disturbance area ratio(0.3835),but poorer soil surface flatness(19.79 mm)and lower soil loosening efficiency(39.35 mm²/N).This study provided critical information for optimizing winged subsoilers on aspects of improving soil loosening effectiveness and reducing draught force.