基于SHPB试验的煤体动态力学特性研究

发布时间：2018-05-01 02:40

本文选题：煤的成块率 + 煤的动态特性　；参考：《安徽理工大学》2017年硕士论文

【摘要】：我国西部煤炭储量丰富,是目前煤炭生产的主产地。然而,由于其成煤特性和生产工艺(包括综采、机运、转载等)的影响和作用,到达用户时原煤较为破碎,粉煤多、成块率低,严重制约了煤炭的使用价值。鉴于此,人们已着手进行各方面的研究,意欲提高原煤的成块率,煤层内超长深孔爆破是为有效技术手段之一,研究煤的动态力学性质是其基础。为此,论文以杨伙盘矿煤的原煤为例,采用实验室冲击试验和数值模拟相结合,进行煤的冲击动态力学特性研究。利用分离式霍普金森压杆(SHPB)实验装置,采用Φ50mm锥形杆对煤进行冲击试验,探究不同气压(0.15MPa、0.20MPa、0.30MPa、0.40MPa、0.50MPa)下煤的动态力学特性。试验分别在无围压和被动围压下进行,速度为2m/s～7m/s。通过采集到的数据,用三波法得到应力、应变和应变率;再用数据处理软件进行处理分析得获得了应力、应变和应变率时程曲线以及应力-应变曲线。实验结果表明:(1)应变率和加载速度相关性明显,通过拟合得到ε=3.750v2-3.624v + 43;随着加载速度的增加,应力-应变曲线整体上升,曲线在加载初期,存在短时间的弹性阶段,之后呈现明显的塑形变形,达到峰值以后,在很短的时间内,应变继续增加,应力保持不变,最后进入卸载阶段,应变会出现回弹现象;(2)被动围压下,煤的抗破坏能力有所增强,应力-应变曲线有所上升,轴向应力比无围压下增加1.0～1.3倍,应变回弹明显,说明套筒可以增强煤试件的抗变形能力。利用ANSYS/LS-DYNA对煤的动态力学性质进行模拟,结果以发现煤的破坏从两端和中间开始,并逐渐贯通,直至破碎。整合数值模拟的应力与应变数据,得到煤的动态应力-应变曲线,相应的加载速度为3m/s、4m/s、5m/s和6m/s。通过比较,该应力与应变的变化趋势与实验曲线吻合,从而证明了实验的正确性。
[Abstract]:The west of China is rich in coal reserves and is the main producing area of coal production at present. However, due to the influence and effect of coal forming characteristics and production technology (including fully mechanized coal mining, mechanical transportation, reloading, etc.), the raw coal is more broken, the pulverized coal is more, and the lump rate is low, which seriously restricts the use value of coal. In view of this, people have begun to carry out various aspects of research, with the intention to improve the block rate of raw coal, the ultra-long deep-hole blasting in coal seam is one of the effective technical means, and the study of dynamic mechanical properties of coal is its basis. Therefore, taking the raw coal of Yangyangpan Coal Mine as an example, the dynamic mechanical properties of coal impact are studied by combining the laboratory impact test with numerical simulation. In this paper, the impact test of coal with 桅 50mm conical rod was carried out by using split Hopkinson pressure bar SHPB. the dynamic mechanical properties of coal under different pressure of 0.15 MPA ~ 0.20 MPA ~ 0.30 MPA ~ 0.40 MPa ~ (0. 50 MPA ~ (-1) were investigated. The experiments were carried out at a speed of 2 m / s to 7 m / s under no confining pressure and passive confining pressure respectively. The stress, strain and strain rate are obtained by three wave method, and the stress, strain and strain rate time history curves and stress-strain curves are obtained by data processing software. The experimental results show that the strain rate has obvious correlation with the loading speed, and the fitting results show that 蔚 = 3.750v2-3.624v 43. With the increase of loading speed, the stress-strain curve increases as a whole, and the curve has a short elastic stage in the early stage of loading. The strain continues to increase in a very short period of time, and the stress remains unchanged. Finally, when the strain enters the unloading stage, the strain will appear springback under passive confining pressure. The failure resistance of coal is enhanced, the stress-strain curve is increased, the axial stress is increased by 1.0 ~ 1.3 times than that without confining pressure, and the strain springback is obvious, which indicates that the sleeve can enhance the deformation resistance of the coal specimen. The dynamic mechanical properties of coal are simulated by ANSYS/LS-DYNA. The results show that the destruction of coal starts from the two ends and the middle, and goes through gradually until it is broken. The dynamic stress-strain curves of coal are obtained by integrating the stress and strain data of numerical simulation. The corresponding loading speeds are 3 m / s ~ 4 m / s ~ 4 m / s ~ 5 m / s and 6 m / s / s. By comparison, the variation trend of the stress and strain is in agreement with the experimental curve, which proves the correctness of the experiment.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD315

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