滚刀振动切削岩石动力学特性

Dynamic Characteristic of Rock Cutting by Vibrational Disc Cutter

为深入研究滚刀振动切削岩石动力学特性,开展了滚刀与岩石互作用力特性以及振动引入对滚刀切削破岩影响的分析,实验结果表明:切削破碎载荷呈近似的刚度双折线特征,滚刀与岩石之间存在弱接触和局部切削行为,适当的振动引入可以明显地提高滚刀切削破岩效率和降低滚刀扭矩。进而,基于弹簧、阻尼、质量块以及滑动器建立了滚刀振动切削岩石动力学模型,构建了包含滚刀与岩石之间五种相互作用形式的连续无量纲方程组,运用四阶龙格-库塔法求解微分方程组,获得了不同参数组合下系统的分岔图、速度、位移、庞加莱截面和相空间轨迹等,结合实验研究表明:所建立的动力学模型能够较好地重现滚刀振动切削岩石过程;破岩系统主要存在周期和混沌运动状态,混沌运动时破岩系统相空间轨迹杂乱,相轨迹没有确定的形状周期,位移和速度随时间变化也没有明显规律,破岩效率一般较低;当静态力、激振力幅值以及激振频率改变时,系统的运动状态和岩石破碎效率也随之发生变化,分析滚刀速度分岔图、岩石破碎位移获得了给定条件下静态力、激振力幅值以及激振频率的较优范围,它们对应的系统运动状态总是为P-1-I-1-Pr-1(滚刀在一个激振周期内碰撞岩石一次,且阶跃性破碎岩石一次)。

To investigate the dynamic characteristics of rock cutting by vibrational disc cutter deeply, the effect of vibration application on rock cutting performance and the interacted force between rock and disc cutter are investigated through experiments,and the results show: the rock cutting force presents approximatively double broken line feature of contact stiffness;there are weak contact and local cutting behaviour between rock and disc cutter;the reasonable vibration application can improve cutting efficiency of disc cutter and reduce cutting torque distinctly. Further, the dynamic model of rock cutting by vibrational disc cutter is developed using spring, damp, mass and slider elements, and the continuous-dimensionless equations including five interaction statuses between disc cutter and rock are established. The bifurcation diagram, velocity, displacement, Poincare section and phase diagram under different conditions are obtained by solving the differential equations, which can conclude some results with experiments: the developed dynamic model can well reappear the rock cutting process by vibrational disc cutter;the cutting system mainly including periodic and chaos motions, the phase diagram, velocity and displacement of cutting system under chaos motion are irregular, and its rock breakage efficiency is generally low;the motion state and rock breakage efficiency alter with the variation of static force,dynamic force amplitude and vibration frequency accordingly;the optimal ranges of static force, dynamic force amplitude and vibration frequency can be obtained according to bifurcation diagram and rock breakage displacement, and the corresponding states of cutting system are always P-1-I-1-Pr-1(one impact between disc cutter and rock in one period, and rock step-breakage once).