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| 基于G2值法的二维光弹颗粒体系力链研究 |
| Study on force chain of a two-dimensional photoelastic particle system based on G2 value method |
| Received:October 28, 2022 Revised:December 17, 2022 |
| DOI：10.7520/1001-4888-22-269 |
| 中文关键词: 颗粒体系 光弹实验 接触向量角度 接触力 力链 |
| 英文关键词:particle system photoelastic experiment contact vector angle contact force force chain |
| 基金项目:国家自然科学基金项目(12072170)；泰山学者工程专项经费资助项目(tsqn202211180) |
| Author Name | Affiliation | | GUO Zhanwei | School of Science, Qingdao University of Technology, Qingdao 266033, Shandong, China | | CHEN Fanxiu* | School of Science, Qingdao University of Technology, Qingdao 266033, Shandong, China | | WANG Yuan | School of Science, Qingdao University of Technology, Qingdao 266033, Shandong, China | | LIU Yuxin | School of Science, Qingdao University of Technology, Qingdao 266033, Shandong, China | | SUN Jie | School of Civil Engineering, Qingdao University of Technology, Qingdao 266033, Shandong, China | | ZHONG Yichen | School of Science, Qingdao University of Technology, Qingdao 266033, Shandong, China |
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| 中文摘要: |
| 力链是颗粒体系研究中的重要概念，是微观现象的集中体现，对宏观颗粒物质体系起着重要作用。采用光弹方法对受竖向荷载作用的混合直径颗粒体系进行加压实验，结合数字图像处理技术和G2值法(彩色梯度均方值算法)，分析了颗粒体系在竖向荷载作用下几何结构的变化以及接触力、力链网络的分布情况。首先通过数字图像处理技术统计出颗粒体系在不同竖向荷载作用下的接触向量角度分布情况，发现其集中分布区间只是在区间分布频率上出现小幅波动，竖向荷载的增大并不会对整体分布产生影响。然后通过G2值法求出了颗粒体系的G2值，并对单个颗粒的G2值和平均接触力F的关系进行了拟合，结果表明，光弹颗粒的G2值随着F的增大而增大，接触点少的颗粒G2值反而偏大。接着通过拟合公式计算出单个颗粒的接触力，根据其与平均接触力的比值频率统计结果画出接触力频率分布曲线，从曲线结果来看，竖向荷载的增大能够让颗粒体系中直径较小的颗粒接触力更加接近平均接触力，分布更加统一；直径较大的颗粒能够支撑起更多的荷载并接触到更多其他的颗粒，承受更大的接触力。最后根据接触力的分布情况判定出强弱力链并画出力链网络，结果表明，竖向荷载的增大在一定范围内会让强力链的分布趋于统一，强力链上的颗粒排列更加紧凑，随着荷载不断增大，强力链上的颗粒数目变少且更易断裂解体成单颗粒分布，进而加剧颗粒的重排性质。 |
| 英文摘要: |
| Force chain is an important concept in the study of particle systems, which is a concentrated embodiment of microscopic phenomena and plays a important role in the material system of macroscopic granular materials. The internal mechanical behavior of the particle system was studied by the photoelastic method, and the geometric information such as the center coordinates and contact point coordinates of the particle material was obtained by using digital image processing technology, the contact network of the entire particle system was obtained, and the changes of the geometric structure and the distribution of contact force and force chain network of two-particle systems of different diameters under vertical load were analyzed. The average color gradient algorithm was used to obtain the G2 value of the photoelastic fringe image and the relationship curve between the loading force and G2 value, the contact force between particles was calculated and got the distribution map of the force chain network. The results show that the G2 value of photoelastic particles increases with the increase of loading force, the G2 value of particles with few contact points is larger, the concentrated distribution interval of contact vector angle only fluctuates slightly in the interval distribution frequency, and the increase of vertical load does not affect the overall distribution. Analyzing the frequency distribution curve of contact force, it can be seen that the increase of vertical load can make the contact force on the smaller diametral 8mm particles in the particle system closer to the average contact force, the distribution is more uniform, and the larger diametral 9mm particles can support more loads and contact more other particles to bear greater contact forces. Studying the distribution of the force chain, it is found that the increase of vertical load within a certain range will make the distribution of the strong chain tend to be unified, and the particle arrangement on the strong chain is more compact, as the load continues to increase, the number of particles on the strong chain will become less and more likely to break and disintegrate into a single particle distribution, thereby aggravating the rearrangement nature of the particles. |
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