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王潇, 陈凡秀, 王远, 刘雨欣, 孙洁. 显微CT探究三维颗粒体系颗粒间力学行为. 力学学报, 2023, 55(8): 1732-1741. DOI: 10.6052/0459-1879-23-161
引用本文: 王潇, 陈凡秀, 王远, 刘雨欣, 孙洁. 显微CT探究三维颗粒体系颗粒间力学行为. 力学学报, 2023, 55(8): 1732-1741. DOI: 10.6052/0459-1879-23-161
Wang Xiao, Chen Fanxiu, Wang Yuan, Liu Yuxin, Sun Jie. The research of inter-particle mechanical behavior in three-dimensional particle system by micro-CT. Chinese Journal of Theoretical and Applied Mechanics, 2023, 55(8): 1732-1741. DOI: 10.6052/0459-1879-23-161
Citation: Wang Xiao, Chen Fanxiu, Wang Yuan, Liu Yuxin, Sun Jie. The research of inter-particle mechanical behavior in three-dimensional particle system by micro-CT. Chinese Journal of Theoretical and Applied Mechanics, 2023, 55(8): 1732-1741. DOI: 10.6052/0459-1879-23-161

显微CT探究三维颗粒体系颗粒间力学行为

THE RESEARCH OF INTER-PARTICLE MECHANICAL BEHAVIOR IN THREE-DIMENSIONAL PARTICLE SYSTEM BY MICRO-CT

  • 摘要: 为描述三维颗粒体系颗粒间的微观力学行为, 以陶粒为研究对象, 利用显微CT开展三维颗粒体系原位加载实验, 获得下压位移间隔为0.2 mm的颗粒二维图像序列. 经三维重构得到颗粒体系的数字体图像, 构建三维颗粒的孔隙网络模型, 计算不同加载状态下的颗粒间接触信息. 对接触信息进行量化统计, 提出以颗粒接触面积衡量接触力的表征方法, 从接触面积、竖向夹角、竖向力和配位数等新视角分析颗粒体系力学性能的变化规律, 描述三维颗粒体系中颗粒间力学行为和力链发展演化的内在联系, 提取强接触颗粒信息并对比颗粒位置坐标变化. 研究结果表明: 加载过程中, 接触数量呈现递减趋势, 强接触占总接触数量的1/3, 平均接触面积基本不变; 颗粒体系内部竖向夹角 \theta < 45o和 \theta > 45o数量占比维持在2:3; 竖向力是接触力和竖向夹角共同作用的结果, 其数值受竖向夹角影响更加显著; 平均配位数整体呈下降趋势, 配位数为3, 4和5的颗粒数量占比约70%; 此外, 颗粒与压头接触点位置影响强接触颗粒坐标变化, 新接触点附近区域往往伴随接触行为的更新.

     

    Abstract: In order to describe the micromechanical behavior between particles of three-dimensional particle system, using ceramic pellets as the object of study, the three-dimensional particle system in-situ loading experiments was conducted by micro-CT to obtain two-dimensional image sequences of particles with a downward pressure displacement interval of 0.2 mm. The digital volume image of the particle system is obtained by three-dimensional reconstruction, and the pore network model of three-dimensional particles is constructed to calculate the inter-particle contact information under different loading states. Based on the quantitative statistics of the contact information, a characterization method to measure contact force by the particle contact area is proposed, the change law of mechanical properties of the particle system is analyzed from the new perspective of contact area, vertical angle, vertical force, coordination number, etc. The intrinsic connection between inter-particle mechanical behavior and evolution of force chain in three-dimensional particle system is described. The information of strong contact particles was extracted and the change of particle position coordinates was compared. The results show that: during the loading process, the number of contacts shows a decreasing trend, the strong contact accounts for 1/3 of the total number of contacts, and the average contact area is basically unchanged. The number of vertical angles \theta < 45o and \theta > 45o in the particle system is maintained at 2:3. The vertical force is the result of the joint action of contact force and vertical angle, its value is more significantly influenced by the vertical angle. The average coordination number showed an overall decreasing trend, the number of particles with coordination number of 3, 4 and 5 accounted for about 70%. In addition, the contact positions of particles and indenter influences change of the strong contact particle coordinates, the region near new contact points is often accompanied by renewal of contact behavior.

     

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