机械式单斗挖掘机挖掘阻力模拟

Simulation on excavating resistance of mechanical single-bucket excavator

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,而本文通过采用离散单元法模拟爆破后矿石的挖掘过程,以预测挖掘阻力。首先将爆破后可挖掘的不规则、不同块度的矿石等效成半径不同的球体离散元,并认为球体半径分布服从高斯分布,离散元之间的接触模拟采用线性刚度模型与滑动接触模型;以Ⅳ级土壤为研究对象、以某样机为例,建立了矿堆模型、铲斗模型和挖掘轨迹。模拟计算表明,预测的挖掘阻力及最大挖掘阻力的作用位置与设计及同类型的某挖掘机测试结果基本符合,挖掘阻力的最小误差为7.4%。该方法具有开拓意义。

At present, the excavating resistance of the mechanical single-bucket excavator was still determinedby the formulae of former Soviet Union, while the paper applied discrete element method to simulate excavation of exploded ore blocks, so as to predict the excavating resistance. First, the various-shaped and various-sized exploded ore blocks were equaled as various-diametered spherical discrete objects that were considered to obey Gauss distribution, and linear rigid model and sliding contact model were applied to the simulation of contact among discrete objects. And then, soil IV was taken as the study objective and a certain excavator prototype as the example, heap model, bucket model and the excavating trajectory were established. Simulation and calculation showed that the predicted excavating resistance and the position of the maximum excavating resistance coincided with the test results of a same-typed excavator with minimum error of excavating resistance being 7.4%. The method was of some innovative signifi cance.