ZHANG Wei, GONG Xu, HAI Bozhan, WU Weichang, LIN Chenkang, LIU Kun
In order to elucidate the mechanical topological characteristics of iron powder pressing process, a numerical analysis model of iron powder pressing particles was established based on the discrete element theory, and the reliability of the model was verified by the pure iron powder pressing experiment conducted on a universal testing machine combined with the compression equation. By studying and simulating different friction factor conditions, combined with the definition of complex networks, and changing the topology-related parameters such as clustering coefficient, average degree and structural path length, the topological characteristics in the powder pressing process were explored. The results show that the number of L3 and L4 cycles composed of three and four particles increases gradually, while the number of L5, L6 and L6+ cycles composed of multiple particles decreases, indicating that the stability of the particle system is improved. In addition, the contact gap of powder particles decreases, the average degree and clustering coefficient of the system tend to decrease, and the structural path gradually becomes shorter, and the system gradually tends to densify. With the decrease of friction factor, the average degree and clustering coefficient increase, the structural path becomes shorter, and the compactness of the system is also improved, but at the same time, the fluidity becomes poor. This study reveals the evolution of the mesostructure of iron granular materials, expands the theoretical basis of the study of fine mechanics and topology of powder compression, and has guiding significance for the improvement of the dense forming of iron powder and different pressing processes.
