基于拟土颗粒DEM数值模型的静态液桥力测试方法

为经济便捷地测定微量液桥力与球颗粒间距的关系,提出基于微量天平的手动与连续测试的方法,能实现两球位置精确移动和间隙调整,观察并记录液桥从拉伸直至断裂的形态和液桥力变化,采用连续测量方式还可自动实现液桥力数值的连续输出。对等径球和异径球液桥力的测试记录与不同公式计算结果的比较表明,手动和连续测试方法具有较高测试精度且经济适用,可用于对不同液桥力公式的精度进行评估;对异径球液桥力的测试与不同公式结果的比较还表明,静态液桥力近似公式简洁明确精度较好,可供选用。

Method of measuring the static liquid bridge force of soil particles based on DEM modeling

In order to numerically predict tillage soil dynamics process,based on the relationship of liquid bridge force and gap width between two particles,a DEM model for wet particle system was set to investigate tillage soil dynamics.Based on Sartorius-microbalances two schemes,for the measurement of static liquid bridge force were proposed:The former was of manual measurement with an x-y-z manual adjustment slide and a digital microscope connected to a laptop,and the later was for automatic measurement with additional parts including a screw slide module driven by a stepping motor.Measurements were carried out for two equal spheres and unequal ones with both schemes,and the results were compared with available analytical equations or fitting ones.The results showed that the experimental set combined with the procedures enabled the evolution of static liquid bridge force with increment of separation and further determined the rupture distance with satisfactory.In conclusion,the approximate equation was suitable for modeling the static liquid bridge force of soil particles.