基于振动模型的掘进机截割系统稳定性预测

Stability Prediction of Roadheader Cutting System Based on Vibration Model

掘进机截割过程受动态径向和轴向载荷影响,截割臂会产生水平和竖直方向的摆动,摆动截割过程由煤岩反作用力产生的截割振动对截齿冲击最大,其振动量大小直接影响截割头的稳定性。为判断截割过程截割载荷是否稳定,首先,基于岩石断裂力学和煤岩破碎理论,建立掘进机截割系统物理本构模型,构建截齿和截割头截割载荷谱函数;其次,基于牛顿差值多项式方法进行截割过程截割稳定性预测,构建多因素耦合的非线性截割系统动力学方程,求解动态振动稳定域截割曲线(截割稳定性叶瓣图);然后,提出一种基于相关系数的无量纲截割振动判定准则,从理论和实际两方面判定截割头不同时刻的截割状态;最后,通过搭建截割系统实验台,进行截割系统模态参数辨识实验,测试破岩过程截割头截齿随机载荷特性,研究不同截割参数组合下截割载荷变化规律,得出截割头转速与截割深度的最佳匹配关系,从而证明截割稳定性叶瓣图的正确性。

The cutting process of roadheader is affected by dynamic radial and axial loads,and the cutting arm will swing in both horizontal and vertical directions.The cutting vibration generated by the reaction force of coal rock in the swing cutting process has the greatest impact on the pick,and its vibration directly affects the stabili-ty of the cutting head.In order to judge whether the cutting load is stable or not,firstly,based on rock fracture mechanics and coal-rock breaking theory,the physical constitutive model of roadheader cutting system is estab-lished,and the cutting load spectrum function of pick and cutting head is constructed.Secondly,based on the Newton difference polynomial method,the cutting stability of the cutting process is predicted,and the dynamic equation of the multi-factor coupled nonlinear cutting system is constructed to solve the cutting curve of the dy-namic vibration stability domain(the cutting stability lobe diagram).A dimensionless cutting vibration criterion based on correlation coefficient is proposed to determine the cutting state of cutting head at different time from both theoretical and physical aspects.Finally,by setting up the cutting system test bench,the modal parameter identification experiment of the cutting system is carried out,the random load characteristics of the cutting head cutting teeth in the rock breaking process are tested,and the cutting load variation law under different cutting parameter combinations is studied.The best matching relationship between the cutting head speed and the cut-ting depth is obtained,which proves the correctness of the cutting stability lobe diagram.