Complex nonlinear behaviors of drilling shaft system in boring and trepanning association deep hole drilling

Nonlinear dynamic behaviors of drilling shaft system in boring and trepanning association deep hole drilling are investigated. The effects of the mass eccentricity and the cutting force fluctuating can be taken into consideration in the model of drilling shaft system. Nonlinear hydrodynamic forces are adopted to increase the numerical accuracy. Based on the isoparametric finite element with eight nodal points method, the nonlinear hydrodynamic forces and their Jacobian matrices of compatible accuracy are calculated simultaneously. To solve the nonlinear dynamic orbit of drilling shaft system, the period T of the periodic orbit of the nonlinear drilling shaft system is drawn into the governing equation of the system explicitly by changing the time scale. Then, the period T is taken as a parameter in the iterations of the shooting method. The periodic orbit and its period of the drilling shaft system are determined rapidly by generalized shooting method. The local stability and dynamic behaviors of periodic motion with the change of the drilling shaft design parameters value are obtained by the Floquet theory. The numerical results indicate the rich and complex dynamic behaviors of the drilling shaft system, such as periodic, quasiperiodic, jumped solution, and coexistence of multisolution and can make a good reference for the dynamic design of drilling shaft system in deep hole drilling.