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颗粒介质的类固-液相变过程除受材料性质影响外,还与其运动速率和密集度有密切关系,而接触时间数和配位数是表征该相变过程中颗粒间相互作用的重要时间和空间参量.本文采用三维离散元方法对不同切变速率和密集度下颗粒介质的动力学行为进行了数值模拟,确定了颗粒材料在类固-液相变过程中接触时间数和配位数的参数特性和演化过程,并结合宏观应力的分布特性,进一步确定了颗粒介质在液态和固态相互转化中的动力学机理,讨论了颗粒介质在由快速流动向慢速、准静态转化的相变过程.通过对颗粒单元相互作用的细观数值模拟,获取了颗粒介质在宏观上的动力学行为,为研究其在不同相态下的本构模型提供了依据.
In addition to the influence of material properties, the solid-liquid phase change process of granular media is closely related to the velocity and concentration of particles. The contact time and coordination number are important time-points to characterize the interaction between particles And spatial parameters.In this paper, the dynamic behavior of granular media under different shear rates and densities was numerically simulated by three-dimensional discrete element method, and the contact time and coordination number The kinetic mechanism of the interaction of granular media with each other in the liquid and solid state was further determined based on the distribution and characteristics of the macroscopic stresses. The effects of granular media on phase transition from rapid flow to slow and quasi-static transformation Through the numerical simulation of the interaction of particle units, the macroscopical dynamic behavior of the particle medium is obtained, which provides a basis for studying its constitutive model in different phase states.