颗粒体系致密化过程力学特性及力链演化的数值模拟

doi:10.12382/bgxb.2025.0690

摘要/Abstract

摘要：

为探索颗粒体系致密化过程力学特性及细观机理，提出位置自动调节的测量球生成方法，建立颗粒体系单轴压缩离散元数值模型，分析了颗粒体系致密化过程位移场与速度场演化规律，研究粒径和加载速度对颗粒体系孔隙率及配位数的影响规律，分析了颗粒体系致密化过程的力链网络演化特性，揭示了颗粒体系致密化过程力学性质影响规律和细观机理。研究结果表明，颗粒体系致密化过程可以分为快速压密、缓慢压密与平稳3个阶段，较宽的粒径分布有助于提高颗粒的填充密度并加快致密化进程，致密化过程中位移场和速度场出现中心化现象；加载速度对孔隙率影响较大，速度在0.05m/s、0.5m/s、1.5m/s与3m/时，孔隙率由35.23%分别下降至27.50%、26.2%、24.4%与22.3%，提高加载速度有利于颗粒体系的压密；颗粒粒径越大，加载过程中颗粒变形越大，接触强度越大。0.8~1.5mm混合粒径组合会显著影响力链的形成方式及受力均匀性，颗粒体系致密化过程中趋于短链主导、长链收缩的稳定状态。

关键词: 颗粒体系, 力学特性, 力链演化, 离散元

Abstract:

To explore the mechanical properties and microscopic mechanisms of particle system densification process，a measurement ball generation method with automatic position adjustment is proposed and a uniaxial compression discrete element numerical model of particle system is established.The evolution laws of displacement field and velocity field of particle system during densification process are analyzed，and the influence laws of particle size and loading speed on porosity and coordination number of particle system are studied.The evolution characteristics of force chain network of particle system during densification process are analyzed，and the influence laws and microscopic mechanisms of mechanical properties of particle system during densification process are revealed.The research results indicate that the densification process of particle systems can be divided into three stages：rapid densification，slow densification，and steady densification.A wider particle size distribution is conducive to improving the filling density of particles and accelerating the densification process.During the densification process，the displacement field and velocity field exhibit a centralization phenomena.The loading speed has a significant impact on porosity The porosity decreases from 35.23% to 27.50%，26.2%，24.4%，and 22.3%，respectively，at speeds of 0.05m/s，0.5m/s，1.5m/s，and 3m/s.Increasing the loading speed is beneficial for the compaction of the particle system.The larger the particle size is，the greater the particle deformation and contact strength are during the loading process.The combination of 0.8-1.5mm mixed particle sizes significantly affects the formation of force chains and the uniformity of stress，leading to a stable state of short chain dominance and long chain shrinkage during the densification process of particle system.

Key words: particle system, mechanical property, force chain evolution, discrete element

于洋, 陈凡秀, 谌俊, 刘睿, 周近强, 吴成成. 颗粒体系致密化过程力学特性及力链演化的数值模拟[J]. 兵工学报, 2025, 46(S1): 250690-.

YU Yang, CHEN Fanxiu, SHEN Jun, LIU Rui, ZHOU Jinqiang, WU Chengcheng. Numerical Simulation of Mechanical Properties and Force Chain Evolution of Granular System during Densification Process[J]. Acta Armamentarii, 2025, 46(S1): 250690-.

图/表 15

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参数	数值
墙体法向刚度k_n/（N·m^-1）	2×10¹²
墙体切向刚度k_s /（N·m^-1）	2×10¹²
墙体摩擦系数μ₁	0.25
阻尼系数	0.7
颗粒密度ρ/（kg·m^-3）	1190
颗粒摩擦系数μ₂	0.25
泊松比ν	0.3
弹性模量E/MPa	109
颗粒粒径R/mm	0.8~1.5
颗粒数量	2×10⁴~6×10⁴

参数	数值
墙体法向刚度k_n/（N·m^-1）	2×10¹²
墙体切向刚度k_s /（N·m^-1）	2×10¹²
墙体摩擦系数μ₁	0.25
阻尼系数	0.7
颗粒密度ρ/（kg·m^-3）	1190
颗粒摩擦系数μ₂	0.25
泊松比ν	0.3
弹性模量E/MPa	109
颗粒粒径R/mm	0.8~1.5
颗粒数量	2×10⁴~6×10⁴

加载速度/ （m·s^-1）	粒径范围/mm
加载速度/ （m·s^-1）	0.8~1.0	1.0~1.2	1.2~1.5	颗粒数量
0.05	100	0	0	66477
0.5	0	100	0	43264
1.5	0	0	100	25796
3	50	25	25	55153

加载速度/ （m·s^-1）	粒径范围/mm
加载速度/ （m·s^-1）	0.8~1.0	1.0~1.2	1.2~1.5	颗粒数量
0.05	100	0	0	66477
0.5	0	100	0	43264
1.5	0	0	100	25796
3	50	25	25	55153

粒径范围/mm	加载速度/ （m·s^-1）	初始状态	快速压密阶段	缓慢压密阶段	平稳阶段
0.8~1.0	0.05	35.23	27.50	24.52	23.16
	0.5	35.23	26.22	22.31	21.48
	1.5	35.23	24.41	20.82	18.82
	3	35.23	22.35	18.33	17.64
1.0~1.2	0.05	35.33	27.50	24.22	23.16
	0.5	35.33	26.82	23.31	21.95
	1.5	35.33	25.41	21.80	19.88
	3	35.33	22.35	19.33	18.59
1.2~1.5	0.05	35.54	31.51	28.01	25.94
	0.5	35.54	29.52	26.06	24.20
	1.5	35.54	27.02	22.80	21.70
	3	35.54	23.35	20.86	20.32
0.8~1.5	0.05	36.51	27.90	24.74	24.1
	0.5	36.51	26.42	23.55	22.52
	1.5	36.51	24.80	20.08	18.82
	3	36.51	22.02	18.02	16.41