何灵空，李传檑，李艳洁
北京林业大学 工学院，北京100083
何灵空，李传檑，李艳洁. 三轴压缩下形态对细长柔性颗粒料床的强度影响机制［J］. 中国粉体技术，2025，31（6）：1-12.
HE Lingkong， LI Chuanlei， LI Yanjie. Mechanism of morphology effects on strength of granular beds with elongated flexible particles under triaxial compression［J］. China Powder Science and Technology，2025，31（6）：1−12.
DOI：10.13732/j.issn.1008-5548.2025.06.011
收稿日期：2024-03-07，修回日期：2025-04-08，上线日期：2025-05-19。
基金项目：国家自然科学基金项目，编号：12202239；
作者简介：何灵空（1999—），男（苗族），硕士生，研究方向为细长柔性颗粒的数值仿真模拟。E-mail：HLKHXY@bjfu. edu. cn。
通信作者：李艳洁（1980—），女，教授，博士，硕士生导师，研究方向为颗粒与粉体材料计算力学。E-mail： liyanjie@bjfu. edu. cn。
摘要：【目的】 通过三轴压缩数值仿真，探究不同排列与编织形态的由球柱单元连接的细长柔性颗粒料床的三轴压缩强度。【方法】 采用离散单元法和三轴压缩数值模拟仿真，分别探讨竖直排列、水平排列、随机排列以及编织形态的细长柔性颗粒料床的三轴压缩强度。【结果】 增大细长柔性颗粒的键弹性模量，有利于增大竖直排列的细长柔性颗粒间的平均接触力和料床标准化偏应力的峰值，有利于提高随机排列的颗粒间平均接触力、料床标准化偏应力的大小，对水平排列的影响不大；相比于水平和竖直排列的细长柔性颗粒，随机排列的能够产生更大的键合力和接触力，能更好地提高料床的标准化偏应力；增大细长柔性颗粒的长径比、改变细长柔性颗粒的编织形态可以使细长柔性颗粒的平均键合力和接触力增大，提高料床的标准化偏应力。【结论】 在三轴压缩中，不同排列形式的细长柔性颗粒对键弹性模量的敏感度不一致，细长柔性颗粒的排列和编织形态对料床的整体强度有着不可忽视的影响；相比于水平和竖直排列以及非编织形态的细长柔性颗粒，随机排列和编织形态的细长柔性颗粒能更好地提升颗粒料床的整体强度。
Objective Previous studies have explored the mechanical response mechanisms of elongated flexible particles under uniaxial compression， shear， and mixing， using both experimental and simulation methods. However， research on elongated flexible particles with different arrangements and woven forms remains limited. To address this gap， the study explores the compressive strength of such particles with different arrangements and woven forms through triaxial compression simulations.
Methods Compared to traditional models， such as spherical chains， elliptical chains， and rod chains， the sphero-cylinder model can more effectively simulate the deformation behavior and mechanical properties of elongated flexible particles of different materials. Therefore， triaxial compression simulations were used to investigate the mechanics of these particles connected by sphero-cylinder elements under different arrangements and woven forms.
Results and Discussion Compared to vertically and horizontally arranged elongated flexible particles， randomly arranged ones generated higher bond forces and bond bending moments， leading to increased normalized deviatoric stress and solid volume fraction in the granular bed. Increasing the bond elastic modulus （Eb ） enhanced the bond force and normalized deviatoric stress of vertically arranged particles at initial axial strains， though its effect diminished at larger strains. For randomly arranged particles， higher Eb significantly elevated both the internal bond forces and inter-particle contact forces， further increasing the normalized deviatoric stress of the bed. However， horizontally arranged particles showed negligible changes in contact force and stress. Additionally， increasing the aspect ratio of randomly arranged particles or weaving them into a net structure greatly improved bond forces and inter-particle contact forces， resulting in higher normalized deviatoric stress and solid volume fraction of the granular bed.
Conclusion During triaxial compression， the overall mechanical strength of granular beds with elongated flexible particles is significantly impacted by particle arrangements and woven forms. The sensitivity of elongated flexible particles to Eb varies across different particle arrangements. Eb more markedly impacts the strength of the granular bed with randomly arranged elongated flexible particles， whereas the strength of granular beds with vertically and horizontally arranged particles is less affected. Granular beds with randomly arranged and woven elongated flexible particles exhibit superior overall strength enhancement compared to horizontal and vertical arrangements or non-woven forms.
Keywords：elongated flexible particle； discrete element method； triaxial compression simulation
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