BTA深孔加工钻杆系统的稳定性及分岔

Stability and Bifurcation of the Drilling Shaft System in Processing Deep Hole Based on Boring and Trepanning Association

研究了BTA深孔加工钻杆系统的稳定性和分岔。考虑了钻杆质量偏心和切削力波动的影响,利用切削液非线性流体力以增加数值计算的精度。通过引入变分约束原理的有限元方法,同时完成了非线性分析所需的流体力及其Jacobian矩阵的计算。在稳定性分析中,通过改变系统的时间尺度,将非线性钻杆系统周期轨迹的周期显式地出现在钻杆系统的系统方程中;然后对传统打靶法进行改造,将周期也作为一个参数一起加入打靶法的迭代过程,确定了钻杆运行周期轨迹并有效减少了周期计算量。结合Floquet稳定性理论,将理论计算与实验结果相结合验证了上述方法的正确性和有效性。

The stability and bifurcation of the drilling shaft system in processing deep hole based on boring and trepanning association were analyzed.Taking effects of the mass eccentricity and the cutting force fluctuating on the stability and bifurcation into account,nonlinear hydrodynamic force was adopted to increase the numerical accuracy.Based on the isoparametric finite element with eight node method,the nonlinear hydrodynamic force and their Jacobian matrices of compatible accuracy were calculated simultaneously.In the stability analysis,by changing the time scale,the period of the periodic orbit of the nonlinear drilling shaft system was drawn into the governing equation of the system explicitly;the generalized shooting procedure was recompiled;the period took part into the iteration procedure of the shooting method as a parameter,and thus the periodic orbit and its period of the drilling shaft system were determined rapidly.Correctness and effectiveness of the proposed method were verified by combining the theoretical computation with the experimented results based on the Floguet stability theory.