Design and experiment of corn low damage threshing device based on DEM

Abstract

Kernel broken rate is an important index to evaluate the maize kernel direct harvesting quality. In view of the problem of the high kernel broken rate in the present maize harvester, a new threshing cylinder was designed in this study. This device utilized rasp bar to achieve low damaged maize ears threshing. In order to determine the structure and working parameters of threshing device, the "crop-crop" contact model and the "crop-mechanical" interaction system were established and analyzed based on the discrete element method first, and the mathematical expressions of the related kinematic response of maize kernel under the external force were obtained. Then, the structure parameters of rasp bar were studied through EDEM simulation experiment, and the working parameters were determined through test-bed experiment. Finally, the simulation experiment results and test-bed experiment results were verified through field experiment. The results showed that when the threshing cylinder speed was 356 r/min, the concave clearance was 40 mm, the installation distance of rasp bar was 250 mm with 50Mn steel, and the feeding amount was 8 kg/s, the kernel broken rate was 1.93%, which satisfied the requirements of maize harvest standard. This study proved that the DEM (Discrete Element Method) can be adopted to guide the optimization design of mechanical structure, and it has certain value for the research and development of operation equipment of other agricultural crops.

Discrete element modeling and parameter calibration of safflower biomechanical properties

“…The p-values of X 6 , X 2 X 3 , and X 2 X 6 were less than 0.05, denoting a significant effect on the stacking angle. The significant factors were retained to establish a quadratic polynomial regression equation so that the accuracy of the response surface can be ensured, as depicted in Equation (10). Note: *indicates significant (0.01<p<0.05), **indicates very significant (p<0.01).…”

“…In summary, the order of influence of the three parameters was X 2 > X 3 > X 6 . The optimization module of the Design-Expert software was used to solve Equation (10) and optimize the regression model and simulation parameters, setting the physical test value of the stacking angle (30.08°) as the target value. The corresponding objective and constraint equations are presented as follows:…”

“…A possible solution to this problem is using discreteelement simulations to study the microscopic mechanisms of safflowers. The discrete element method (DEM) has significant advantages when studying the biomechanical properties of crops and their mechanical interaction [10][11][12] . Therefore, establishing a discrete element model of safflower can expedite the in-depth exploration of its biomechanical properties and provide a theoretical basis for designing corresponding machinery.…”

Multiparameter collaborative optimization of the vibrating screen based on the behavior of oil sunflower seed penetrating screen holes

“…There was no adhesion between the oil sunflower seeds and no additional resistance when the particles moved on the vibrating screen. Therefore, the simulation analysis of the oil sunflower seed motion process was based on the Hertz-Mindlin no-slip contact model [24][25][26] . In this study, a multi-sphere cluster combination filling method was used to fill the oil sunflower seeds.…”