基于离散单元法的机械式挖掘机工作阻力模拟

发布时间：2018-07-23 19:56

【摘要】：矿用机械式挖掘机挖掘过程是复杂的物理过程,矿岩的挖掘阻力是设计挖掘机的主要参数之一,它直接关系到挖掘机的结构、机械强度、机重、传动方式和功率选择,该指标的准确程度对挖掘机的设计起着重要作用。目前我国机械式单斗挖掘机的挖掘阻力确定仍然采用前苏联20世纪50年代提出的计算公式。影响挖掘阻力因素主要有：土样种类、斗齿形状与爆破矿石块度。本文以矿用55m3机械式挖掘机为例,以相同土样、相同斗形,不同块度的爆破岩石为研究对象,利用离散单元理论,通过EDEM软件仿真模拟,将不同块度的爆破后风化岩石模拟为球形离散元,分析三组颗粒大小,并认为服从正态分布,建立矿堆模型、铲斗模型、挖掘轨迹得到挖掘过程中铲斗沿X方向、Y方向及Z方向的阻力曲线,通过计算得到最大切向挖掘阻力、最大法向挖掘阻力、其及出现的时间与此时的挖掘厚度。分析得到随着块度粒径的增加,最大切向挖掘阻力与最大法向挖掘阻力均增大,而出现最大挖掘阻力时斗杆的总转角与此时的挖掘厚度变化趋势大体相同。当矿石粒径主要集中在(1.3-1.6)m时,离散单元法预测最大切向阻力误差为2.63%；最大法向阻力误差为2.14%；测量提升力误差为2.98%；测量推压力误差为3.48%。当矿石粒径主要集中在(1.0～1.3)m时,离散单元法预测最大切向阻力误差为13.98%；最大法向阻力误差为12.22%；测量提升力误差为9.53%；测量推压力误差为13.69%。以上误差均在工程上可接受范围内,可见离散单元法可以作为研究挖掘过程中挖掘阻力的一种研究手段。
[Abstract]:Mining process of mining mechanical excavator is a complicated physical process. Mining resistance of ore rock is one of the main parameters of excavator design. It is directly related to the structure, mechanical strength, machine weight, transmission mode and power selection of excavator. The accuracy of this index plays an important role in the design of excavator. At present, the excavating resistance of mechanical single bucket excavator in our country is still determined by the formula put forward by the former Soviet Union in 1950s. The main factors affecting excavation resistance are: soil sample type, bucket tooth shape and blasting ore fragmentation. Taking mine 55m3 mechanical excavator as an example, the blasting rock with the same soil sample, the same bucket shape and different pieces of rock is taken as the research object. The discrete element theory is used to simulate the blasting rock by EDEM software. The weathered rock after blasting with different degrees of fragmentation is simulated as a spherical discrete element. The size of three groups of particles is analyzed, and it is considered that the ore heap model and bucket model are established according to normal distribution. The resistance curves of bucket along X direction Y direction and Z direction are obtained in the excavation process. The maximum tangential excavation resistance and the maximum normal excavation resistance are obtained by calculation, and the time when the bucket appears and the excavation thickness at this time are obtained. The results show that the maximum tangential excavation resistance and the maximum normal excavation resistance increase with the increase of the block size, and the total rotation angle of the bucket rod is approximately the same as that of the mining thickness when the maximum excavation resistance occurs. When the ore diameter is mainly concentrated at (1.3-1.6) m, the maximum tangential resistance error is 2.63, the maximum normal resistance error is 2.14, the lifting force error is 2.98 and the thrust pressure error is 3.48. When the ore diameter is mainly concentrated at (1.0 ~ 1.3) m, the maximum tangential resistance error is 13.98, the maximum normal resistance error is 12.2222, the lifting force error is 9.53 and the pressure error is 13.69. The above errors are all acceptable in engineering, so the discrete element method can be used as a research method to study the excavation resistance in the process of mining.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU621

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