二维液桥计算模型及湿颗粒材料离散元模拟

摘要

The critical rupture distance of the binary liquid bridge between two neighboring particles and the numerical procedure to compute the capillary force due to the liquid bridge are studied.The fitting formula to determine the critical rupture distance of the liquid bridge expressed in terms of radii of the two particles,the contact angle and the volume of interstitial liquid is derived.The relationship between the capillary force of the liquid bridge of binary contacting or non-contacting particles and the volume of liquid in the liquid bridge are given.The Voronoi cell is introduced to define the degree of averaged satu-ration of the pore liquid at a meso-structured material point attributed to the reference particle.The DEM model for wet particulate systems taking into account the effect of the liquid bridge is proposed. The numerical results obtained by the proposed DEM model demonstrate the effects of the capillary forces related to different uniform distributions of degree of initial saturation of pore liquid in the wet par-ticulate system and the capability of capturing the failure modes characterized with strain localization phenomena.%本文研究了二维情况两直接相邻颗粒间液体以液桥形式存在时的液桥临界断裂距离及液桥力的计算过程。导出了用颗粒半径、三相接触角和液桥体积表示的二维液桥临界断裂距离拟合公式及两个接触或非接触颗粒间液桥毛细力随液桥体积的变化关系。引入 Voronoi胞元计算定义基于参考颗粒介观结构的物质点的平均饱和度。提出了考虑液桥效应的二维湿颗粒离散元模型，并用以模拟不同初始均匀饱和度下湿颗粒集合体中的吸力效应，验证其有效捕捉以应变局部化为特征的破坏模式的能力。