STUDY AND EXPERIMENT ON A CORN FLEXIBLE THRESHING TECHNOLOGY WITH SINGLE-POINT HINGED STRUCTURE BASED ON DEM-MBD COUPLING

To address the issues of high kernel breakage rate and poor flexibility adaptation in threshing devices for direct corn kernel harvesting, this study proposes a flexible threshing device based on a single-point hinged structure. In this design, the threshing elements are flexibly mounted via single-point hinges, allowing them to rotate upon impacting corn kernels. This rotational motion provides an impact-buffering effect during the threshing process, thereby reducing the risk of kernel breakage.By comparing the dynamic characteristics of the single-point hinged flexible structure with those of a rigid structure, the superiority of the proposed device is confirmed. A contact force model is established to analyze key parameters influencing threshing performance, identifying the mass of the threshing element, rotational speed, and structural configuration as the primary influencing factors. A coupled simulation model was developed using RecurDyn and EDEM software to investigate the effects of threshing element mass, rotational speed, and structural configuration on the kernel breakage rate and unthreshed rate of the device, and to determine the optimal parameter range. Based on a three-factor, three-level orthogonal experimental design, the optimal working parameters of the device were identified as follows: threshing element mass of 200 g, rotational speed of 600 r/min, and a composite structural configuration. Under these conditions, the kernel breakage rate was 3.95% and the unthreshed rate was 0.88%, meeting the practical requirements for harvesting performance. This study provides theoretical support and a technical pathway for the design of high-efficiency, low-damage threshing devices for direct corn kernel harvesting.