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DEM investigation of macro- and micro-mechanical properties of rigid-grain and soft-chip mixtures
Particuology ( IF 4.1 ) Pub Date : 2020-07-07 , DOI: 10.1016/j.partic.2020.06.002
Junqi Zhang , Xiaobin Chen , Jiasheng Zhang , Peerapong Jitsangiam , Xiang Wang

We investigated the macro- and micro-mechanical properties of rigid-grain and soft-chip mixtures (GCMs) through numerical simulations using the discrete element method. We present a novel framework for the discrete modeling of soft chips and rigid grains in conjunction with calibration processes. Several numerical triaxial tests were also performed on GCMs with 0%, 10%, 20%, and 30% volumetric chip contents, P. The simulation results demonstrate that increasing P leads to higher GCM toughness, higher deviatoric peak stress, and higher corresponding shear strain. Higher P also contributes to more volume contraction and less dilation. The friction angles at both the peak and residual state significantly increase with increasing P. In view of the micro-mechanical features, strong contact force chains develop along the loading direction, which results in considerable anisotropy in the peak and residual states. Both the formation of strong force chains and rotation of grains decrease with increasing P, whereas the grain sliding percentage increases. The tensile force is mobilized with shearing and higher P leads to less mobilization of the tensile force. These findings are useful for better understanding the internal structure of GCMs with different soft-chip contents, especially in granular mixture mechanics and geomechanics.



中文翻译:

硬质和软质合金混合物的宏观和微观力学性能的DEM研究

通过使用离散元方法的数值模拟,我们研究了硬颗粒和软片混合物(GCM)的宏观和微观力学性能。我们提出了一种新颖的框架,用于结合校正过程对软屑和硬质颗粒进行离散建模。还对体积碎片含量为P的0%,10%,20%和30%的GCM进行了一些数值三轴试验。仿真结果表明,增加P会导致更高的GCM韧性,更高的偏斜峰值应力和更高的相应剪切应变。较高的P也有助于更大的体积收缩和更少的扩张。峰值和残余态的摩擦角均随着P的增加而显着增加。鉴于微机械特征,沿加载方向会形成很强的接触力链,这会导致峰态和残余态具有相当大的各向异性。随着P的增加,强力链的形成和晶粒的旋转都减小,而晶粒的滑动百分数增加。拉力通过剪切而动员,较高的P导致拉力的动员较少。这些发现有助于更好地理解具有不同软片含量的GCM的内部结构,尤其是在颗粒混合物力学和地质力学中。

更新日期:2020-07-07
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