碟盘刀具振动切削煤岩的理论力学模型与载荷特性

Theoretical mechanical model and load characteristics of coal and rock vibra-tion cutting with disc cutter

  • 摘要: 针对煤岩机械刀具破碎煤岩寿命和效率低的问题,提出一种具有轴向振动与径向切削破碎煤岩的方法,为探明碟盘刀具在轴向振动与径向切削破碎煤岩的力学特性,通过分析煤岩崩落面积、当量崩落角、载荷的集中力及其作用位置角,以单位断裂面上受力极限强度和最小能量法的准则,构建碟盘刀具破碎煤岩力学模型。基于扩展线性Drucker-Prager塑性本构模型,采用ABAQUS软件模拟碟盘刀具破碎煤岩的应力云图和载荷特性,在振动切削试验台上通过设定振动频率和振幅等参数测试不同切削厚度下的碟盘刀具破碎煤岩的载荷谱,提取数值模拟和试验碟盘刀具破碎煤岩的载荷特征,对比分析理论模型计算值与数值模拟载荷峰值均值和数值模拟峰值的均值。结果表明:碟盘刀具破碎煤岩的破裂范围呈现月牙状,由中间向两侧递减;振动切削煤岩时其径向载荷明显小于单作用径向切削煤岩的载荷;碟盘刀具在轴向振动与径向切削时不同切削厚度径向载荷理论模型计算值与数值模拟载荷峰值均值的平均误差为9.12%,与试验载荷峰值均值的平均误差为4.88%;轴向载荷理论模型计算值与数值模拟载荷峰值均值的平均误差为9.25%,与试验载荷峰值均值的平均误差为8.34%。通过数值模拟和试验研究验证了碟盘刀具理论模型的准确性,为高效破碎煤岩的截割刀具研制与解决高效掘进硬煤岩巷道截割技术的瓶颈奠定了基础。

     

    Abstract: Aiming at the problem of short life and low efficiency of coal rock cutting machine,a method of cutting coal and rock with axial vibration and radial cutting is proposed to investigate the mechanical properties of the disc cutter in the axial vibration and radial cutting of the fractured coal-rock,the mechanical model of breaking coal and rock with disc cutter is constructed according to the criterion of ultimate strength per unit fracture surface and minimum energy method based on the analysis of caving area and equivalent caving angle and the concentrated force of load and its action position angle. Based on the extended linear Drucker-Prager plastic constitutive model,the stress cloud and load characteristics of the disk rock crushed is simulated using the ABAQUS software. The discs under different cutting thicknesses are tested on the vibration cutting test bench by setting parameters such as vibration frequency and amplitude. The load spectrum of the broken coal rock of the disc cutter,the numerical simulation and the load characteristics of the crushed coal rock of the disc cutter are extracted. The average value of the theoretical model calculation value and the numerical simulation load peak mean value and numerical simulation peak value are compared and analyzed.The results show that the fracture range of coal-rock broken by disc cutter is crescent shape and decreases from middle to both sides. The radial load of the cutting coal-rock is obviously smaller than that of the single-acting radial cutting coal-rock. When the disc cutter is in axial vibration and radial cutting,the average error between the theoretical model of radial load with different cutting thickness and the mean value of peak value of simulated load is 9. 12% and 4. 88% . The average error between the theoretical model of axial load and the mean value of peak value of numerical simulation load is 9. 25% ,and the average error between the theoretical model of axial load and the mean value of peak value of experimental load is 8. 34% . The accuracy of the theoretical model of the disc cutter is verified by numerical simulation and experiment.

     

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