Discrete Element Method Analysis of the Impact Forces on a Garlic Bulb by the Roller of a Garlic Harvester

Abstract

The discrete element method can be used to simulate particle systems and identify forces acting on a particle, but the suitability of using simulation for the modeling of garlic is undetermined. This study was conducted to evaluate the feasibility of using the EDEM program as a simulation tool for garlic bulbs in a garlic harvester. Simulations were compared with experimental collisions between a bulb and the roller of a garlic harvester. In the collision tests, the behavior and impact of an artificial garlic were observed with a high-speed camera and an accelerometer. The simulated positions and accelerations of the garlic were obtained in EDEM using the same parameters as those of the experiment. The impacts of the garlic were compared in terms of the root mean square of acceleration, contact number, and average force for roller speeds of 100–300 rpm. Based on similar behavior observed from photographic images of the experiments, the collision of garlic can be simulated in EDEM. The simulated accelerations were 2.8–7.8 times larger than the measured accelerations, which is attributed to an experimental limitation. The difference was reduced to 1.18 times after applying this limitation to the simulated data. In the simulations, the number of collisions decreased from 185 to 93 as the rotational speed increased, but the average force increased from 3.188 to 6.222 N. EDEM is suitable for simulating the collision of garlic with harvester conveying rollers. Therefore, EDEM can be applied to evaluate the impact forces acting on the garlic and to improve the structure of garlic harvesters.