*Article* **Measurement and Calibration of DEM Parameters of Soybean Seed Particles**

**Dongxu Yan 1, Jianqun Yu 2, Yang Wang 2, Kai Sun 2, Long Zhou 3, Ye Tian <sup>4</sup> and Na Zhang 2,\***

<sup>1</sup> Hua Lookeng Honors College, Changzhou University, Changzhou 213164, China


**Abstract:** In discrete element method (DEM) simulations, accurate simulation parameters are very important. For ellipsoidal soybean seed particles, the rolling friction coefficient between seed particles (RFCP-P) and the rolling friction coefficients between seed particle and boundary (RFCP-B) are difficult to measure experimentally and therefore need to be calibrated. In this paper, soybean seed particles of three varieties with different sphericities were taken as the research objects. Through the simulation analysis of repose angle and self-flow screening, it was shown that the above two parameters needed to be accurately calibrated. In addition, the sensitivity of the RFCP-P and RFCP-B to the angle of repose was analyzed by simulating the repose angle test. The results showed that the RFCP-P had a significant effect on the test results of the repose angle, and the RFCP-B had little effect on the test results of the repose angle. Therefore, the RFCP-P was calibrated using a single-factor test of repose angle, and the RFCP-B was calibrated using the repose angle test with soybean particles mixed with organic glass spheres. The accuracy of the calibration parameters was verified by rotating cylinder test and self-flow screening test.

**Keywords:** discrete element method; soybean seed; ellipsoidal shape; parameter calibration; rolling friction coefficient
