中文摘要：

颗粒团聚体在加工过程中的分散效果直接影响了复合材料的综合性能.为研究颗粒团聚体在流场中的分散机理及动态细节,考虑颗粒间范德华力的作用,采用自主开发的三维颗粒离散元程序DEMix3D对分形结构团聚体在简单剪切流场中的变形和分散过程进行数值模拟,并分析团聚体在分散过程中细观结构的变化规律.研究发现：强弱力链交织形成了团聚体复杂的力链网络形态,强力链主要分布在力链网络内部,传递较大份额的流场作用力,弱力链传递小份额的流场作用力并充分分布在力链网络中;分散过程中团聚体力链结构的变化直接决定了颗粒的分散方式;当分散达到平衡状态时,碎片内的颗粒之间由于形成以强力链为主的紧密接触关系而不再分散.文中还根据碎片加权平均颗粒数的变化规律分析了流场强度对团聚体分散效果的影响.

英文摘要：

The dispersion effect of particle aggregates has a direct impact on the comprehensive properties of com- posite materials. In order to reveal the dispersion mechanism and dynamic details of particle aggregates, a 3 D dis- crete element program, Demix3 D, which involves the van der Waals force among particulates, is developed to nu- merically simulate the deformation and dispersion process of aggregates in a simple shear flow field, and to further explore the mesostructure evolution of the aggregates in the dispersion process. The results show that complex force chain network caused by the interwining of strong and weak force chains form in the aggregates. In this network, the strong force chains mainly distribute in the interior and transfer the majority of the force from the flow field, while the weak force chains fully distribute in the network and transfer the minority of the force. Moreover, it is found that the dispersion mode of the particles is directly determined by the evolution of the force chain network, and that the fragments no longer disperse due to the close contact among the particles with strong force chains when the dispersion of the particles reaches its equilibrium. In addition, the effect of flow field intensity on the dispersion of the aggregates is analyzed according to the weighted average particle number of the fragments .