The coefficient of rolling friction is a foundation parameter for conducting particles simulation, however, which of irregularly shaped maize seeds is difficult to measure. Furthermore, the coefficient of rolling friction between the simulation particles and the actual seeds is inconsistent due to the shaped difference of model and different position of gravity center. This paper use two methods to determinate the coefficient of rolling friction based on discrete element method (DEM) and physical experiments. Three types of maize models from five different shaped maize samples (including horse-tooth shape, spherical cone shape, spherical shape, oblate shape, irregular shape) were developed with the help of slice modeling and 3D modeling technology. Aluminum cylinder container is used to arrange the simulation experiments of angle of repose with taking the coefficient of rolling friction as independent variables and the simulation angle of repose as target values. After predicting detailed the coefficient of rolling friction (including horse-tooth shape, spherical cone shape, spherical shape, between horse-tooth shape and spherical cone shape, between horse-tooth shape and spherical shape, between spherical shape and spherical cone shape maize models), and forecasting a unified the coefficient of rolling friction among horse-tooth shape, spherical cone shape and spherical shape maize models, two types of materials (aluminum cylinder container and organic glass container) were used to validate the difference the angle of repose between the simulation maize models and actual maize seeds. Results show the relative error of the angle of repose between the maize models controlled by the coefficient of rolling friction through the detailed method and the actual maize seeds is 0.22%, 0.33% in aluminum cylinder, organic glass container, respectively. The relative error of the angle of repose between the simulation maize models controlled by the coefficient of rolling friction through the united method and actual maize seeds is 2.47%, 2.97% in aluminum cylinder, organic glass container, respectively. Although the difference of the angle of repose between two method is smaller, the detailed method is better. Moreover, From the accumulation process of the angle of repose we found that the difference on the contacts number between maize models and bottom plate, the change curve of the rotational kinetic energy, the potential energy of maize models controlled by the coefficient of rolling friction through the detailed and the united method are evidently. We can choose a better method to predict the coefficient of rolling friction of maize seeds according to the application situation and investigation objective of irregular maize seeds. The results can provide a theoretical basis for designing and optimizing the structure of the seed-metering machine with DEM.
Aim of study: To study the effect of potato surface with or without sandy loam soil on seed metering performance, we investigated the motion behaviour of the potato seed particles during the seed metering process using a self-designed across-bridge metering device by discrete element method (DEM). Area of study: Tonganyi Town, Dingxi, Gansu, China Material and methods: First, the contact characteristics of potatoes were measured using some novel devices. Second, simulations were performed under the same experimental conditions to verify the reliability of the contact parameters. Finally, the velocity and angular velocity of the seed in the seed box and the number of seeds taken by the large spoon during the taking and clearing process were analysed using ANOVA. Main results: The coefficients of static friction (SF) and rolling friction (RF) of seed particles with soil were smaller than those without soil and had the highest values between particles and plastic, followed by between particles and steel, and between particles. Further, the rates of metering single seed particle in simulation and experiment were 98.17% and 97.57%, respectively. The rate of missing seed particles was 1.83% and 2.43%, respectively; it was found to significantly decrease as RF increased from 0.01 to 0.06 to 0.12, and the resultant angular velocity and velocity also significantly decreased as SF increased from 0.1 to 0.5 to 1.0. In addition, the number of seeds taken by the large spoon also reduced. Research highlights: Therefore, potato seed particles surface with or without soil can significantly affect the seeding performance and highlight the need for surface treatment using mechanised metering.
The coefficient of static friction (SF), the coefficient of rolling friction (RF) for particles are two key parameters affecting the repose angle formation and flow characteristics. In this paper, the interaction effects of SF and RF on the formation process of corn repose angle was investigated by the discrete element method. Firstly, five shape kinds of corn models (horse tooth, spherical cone, spheroid, oblate, and irregular shape) were established. Secondly, aluminum cylinder and organic glass box were used to conduct the simulation experiments with taking SF and RF as independent factors and seeing the repose angle as dependent value. Based on simulation results the regression equations were established. Simulation results showed the relation between two factors and the rotational kinetic energy is not nonlinear, and SF does not significantly restrict the flow of corn models after increasing the flow direction, and the effect of SF on the contact number between corns and the bottom plate is remarkable, while the effect of RF on the contact number is not remarkable. Finally, the interaction effect of two factors on the repose angle was analyzed by variance analysis and results showed SF and RF all have a significant impact on the repose angle. Moreover, their interaction effect has an impact on the repose angle.
In the dry areas of Northwest China, cavity planters with vertical insertions are used for seeding on film. Due to the uncertain mechanism between cavity planters and maize seeds and soil, research on the cavity planter has been slow. Several theoretical and experimental methods have been developed to investigate the interaction between the cavity planter and maize seeds in soil. These methods enable exploration of the mechanism to reduce soil disturbance and improve seeding performance. However, these methods are unable to predict the dynamic force of tools and soil behavior because of non-linear soil properties. A simulation experiment was conducted using the DEM-MBD coupling method to explore soil disturbance caused by cavity seeders and the resistance to entry. Additionally, the effect of the maize shape and the cavity planter motion on the seed number qualification and the empty cavity rate was investigated. It was proposed that the inverted hook be used to prevent the movement of maize seeds up and down in cavity seeders, thereby improving seed filling performance. Simulations and experiments were conducted, and the results showed that the average empty cavity rate and the seed number qualification were 2.0% and 91.3%, respectively, which met the requirements of the maize sowing standards.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.