| 颗粒介质固-流态转变的理论分析及实验研究 |
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| 引用本文： | 费明龙,徐小蓉,孙其诚,周公旦,金峰.颗粒介质固-流态转变的理论分析及实验研究[J].力学学报,2016,48(1):48-55. |
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| 作者姓名： | 费明龙 徐小蓉 孙其诚 周公旦 金峰 |
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| 作者单位： | 1. 清华大学水沙科学与水利水电工程国家重点实验室, 北京 100084;
2. 中国科学院水利部成都山地灾害与环境研究所, 成都 610041 |
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| 基金项目： | 国家自然科学基金项目(11272048;51239006)，欧盟Marie Curie国际项目(IRSES-294976)，美国全球创新计划，清华大学自主科研计划资助 |
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| 摘 要： | 颗粒介质由大量离散的颗粒聚集而成,因而与传统固体和流体不同,运动过程中的颗粒介质中可能同时存在多种流态及其相互间复杂的转换过程.颗粒介质弹性失稳机理、不可恢复应变量化是研究颗粒介质固态和流态及固-流态转变的关键.在前期建立的双颗粒温度热力学(two-granular-temperature,TGT)理论基础上,确定了颗粒介质的弹性稳定性条件,建立了不可恢复应变流动法则,搭建了描述颗粒固态-液态及其相互转化的简单模型.颗粒堆积体坍塌过程是典型的颗粒介质固态和流态及其转变过程,因此本文首先开展了25 167个陶颗粒堆积体坍塌过程的实验研究,并使用基于TGT理论的物质点方法和离散元方法对物理实验进行了模拟.结果表明,模型数值结果与物理实验在颗粒堆坍塌过程中的形态、速度分布等细节上吻合很好,同时也发现了现阶段所使用的物质点方法和TGT理论的不足.初步说明TGT理论可以实现颗粒介质固态和流态,以及状态转变的描述.
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| 关 键 词： | 颗粒介质 热力学 物质点法 弹性稳定性条件 |
| 收稿时间： | 2015-07-30 |
| 修稿时间： | 2015-08-24 |
STUDIES ON THE TRANSITION BETWEEN SOLID-AND FLUID-LIKE STATES OF GRANULAR MATERIALS |
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| Fei Minglong,Xu Xiaorong,Sun Qicheng,Zhou Gordon G D,Jin Feng.STUDIES ON THE TRANSITION BETWEEN SOLID-AND FLUID-LIKE STATES OF GRANULAR MATERIALS[J].chinese journal of theoretical and applied mechanics,2016,48(1):48-55. |
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| Authors: | Fei Minglong Xu Xiaorong Sun Qicheng Zhou Gordon G D Jin Feng |
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| Affiliation: | 1. State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084, China;
2. Institute of Mountain Hazards and Environment IMHE, Chinese Academy of Sciences, Chengdu 610041, China |
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| Abstract: | Not like the traditional fluid or solid, granular media is a combination of large amounts of discrete particles, which may lead to the coexistence of di erent flow regimes and their complex transitions between each other in granular media during its movement. Elastic instability and irreversible flow rule are the keys to understand the mechanical behaviours of granular solid and granular fluid, and especially the phase transition from granular solid to granular fluid. In this paper, we deduced the instable critical condition for instant elastic energy based on the two-granular-temperature thermodynamics (TGT) for granular media, and developed a related irreversible flow rule, with a MPM numerical model we built and used it to simulate a sandpile collapsing, which is a typical transition process between granular solid and granular fluid. Physical experiment and DEM simulation were carried out for comparison, and both numerical results can march well with those from the experiment. We also found out some disadvantages for TGT model and MPM. In this work, the sand dam developed from static compression to irreversible flow after failure, then finally deposited again, and the TGT model and MPM shows the capacity of describing the solid- and fluid-like behaviour, and the phase transition of granular media well during the sandpile collapse. |
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| Keywords: | granular material thermodynamics material point method elasticity stability condition |
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