关键词: 皂荚, 壳籽分离, 离散元法, 参数标定

Abstract:  This study focuses on addressing the issues of low fragmentation rate of Gleditsia shell and the resulting low separation efficiency due to sieve hole blockage in the process of striking shell seeds. The influence of roller speed on the separation of Gleditsia shell seeds is investigated. The HertzMindlin with bonding model (HertzMindlin with bonding) was established using the discrete element method based on the study of the mechanical properties of the Gleditsia shell, and the bonding parameters of the model were calibrated. The normal stiffness, tangential stiffness, critical normal stress, and critical tangential stress of the Gleditsia shell bonding model were determined as 1.8MPa, 1.35MPa, 1.41MPa, and 0.59MPa, respectively. EDEM software was used to simulate and analyze the separation process of Gleditsia sinensis shell seeds. The simulation results showed that the fragmentation rates of Gleditsia sinensis shell were 41.7%, 65.96%, 88.3%, 94.52%, and 94.8, when the roller rotation speed of 200r/min, 360r/min, 400r/min, 500r/min, and 1 000r/min, respectively. When the rotational speed was 500r/min and 1 000r/min, there was no significant change in the fragmentation rate. The primary forms of shell fragmentation were impact crushing and extrusion crushing, resulting in three material forms: dust, filamentous, and incomplete fragmentation. Prototype testing confirms that a roller speed of 500r/min yields a higher fragmentation rate of Gleditsia shell and promotes the formation of filamentous materials, which facilitates the separation of Gleditsia shell seeds and reduces sieve clogging.

Key words: Gleditsia sinensis, shell seed separation, discrete element method, parameter calibration