Investigating the interactions of granular fertilizers with various types of equipment is an essential part of agricultural research. A numerical technique simulating the mechanical behavior of granular assemblies has the advantage of data trackings, such as the trajectories, velocities, and transient forces of the particles at any stage of the test. The interaction parameters were calibrated to simulate responses of granular fertilizers in EDEM, a discrete element method (DEM) software. Without a proper calibration of the interaction parameters between the granular fertilizers and various materials, the simulations may not represent the real behavior of the granular fertilizers. Therefore, in this study, a strategy is presented to identify and select a set of DEM input parameters of granular fertilizers using the central composite design (CCD) to establish the nonlinear relationship between the dynamic macroscopic granular fertilizer properties and the DEM parameters. The determined interaction properties can be used to simulate granular fertilizers in EDEM.

The interaction properties of the seeds have to be calibrated to simulate the realistic behavior of the seed bulk. Here, a simple and accurate calibration method of DEM interaction properties of seeds with adequate equipment to simulate each seed’s behavior remains a challenge. In this research, the rotary drum is chosen as simple equipment to calibrate particle–particle and particle–material interaction properties, as there is a lack of research on whether the rotary drum is adequate equipment to calibrate particle–material interaction properties. Therefore, this article calibrates particle–particle and particle–material static and rolling interaction coefficients using a rotary drum. The calibration of particle–material static and rolling friction coefficients are described using the rotating drum with a 45 degrees inclination. The particle–particle static and rolling friction coefficients were calibrated according to the angle of repose when the rotary drum is vertical.

Investigation of the pin-roller metering device and tube effect for wheat seeds and granular fertilizers based on DEM

Robotic apple harvesting requires the motion planning of a series of movements to perform the efficient picking of fruit without bruises. To optimize the picking motion of apple-harvesting robots and reduce the payload at the end of the robotic arm,...

In this study, an air-assisted mechanical seed-metering device for millet (Setariaitalica) was developed. The discrete element method (DEM) and response surface method (RSM) were used to research the influences of the side length, depth, and oblique...

CrN/DLC composited coatings were deposited on 431 stainless steel, and their structure was analyzed, with particular emphasis on the influence of CrN content on the coating properties. X-ray photoelectron spectroscopy (XPS), nanoindentation testing, scratch testing, and reciprocating tribometry were employed to characterize the chemical composition, mechanical properties, adhesion strength, and tribological performance of the coatings, respectively. Structural analysis indicates that when the ratio of CrN/Cr₂N is relatively low (<1), a high content of chromium dinitride (Cr₂N) is formed in the interlayers, resulting in a porous and loose coating structure. When the ratio achieves 1:1, an optimal balance, with the CrN content reaching a maximum of 21.04% and the Cr₂N content decreasing to a minimum of 20.68%, the densification degree of the coatings is increased, the coating adhesion strength is improved to 11.87 N. Meanwhile, the enhanced formation of the CrN phase improves the hardness to 12.27 GPa. Tribological test results demonstrate that when the ratio is approximately 1:1, the coating exhibits the lowest friction coefficients under dry sliding, deionized water, and artificial seawater conditions (0.0932, 0.1409, and 0.1021, respectively), as well as the minimum wear rates. With the decrease in CrN content of the coatings, the interfacial mismatch degree of the coatings is aggravated, which leads to not only more interfacial defects but also a relatively loose structure, as well as a decrease in the bonding strength (6.81 N), hardness (5.22 GPa), and deformation resistance. Therefore, an excessive Cr₂N phase may degrade the hardness-to-elastic modulus ratio (H/E) of the coatings by increasing interfacial mismatch and reducing structural compactness.