Nonlinear dynamics of friction-induced regenerative chatter in internal turning with process damping forces

Stability in internal turning operation depends on several factors such as cutting conditions, tool overhang, associated tool dynamics, regeneration, friction and process damping. In the present work, an improved friction-induced regenerative chatter mechanism is introduced for internal turning operations with the help of a two-degree of freedom (DOF) cutting tool model by considering structural nonlinearities and process damping effects. The model is initially validated with the existing linear stability analysis theory via the natural parameter continuation method. The stability lobes obtained from the proposed model predict the stable regions with good accuracy. Furthermore, the nonlinear behaviour of the cutting tool with Stribeck and regenerative effects under internal resonance and primary resonance conditions is investigated. The nonlinear dynamic responses and the cutting stability are predicted using the higher-order method of multiple time scales (MMTS). The effect of nonlinearities on the frequency response and stability is studied in detail and the system parameters for stable cutting operations are identified. In order to validate the cutting states of the stability diagrams, internal turning experiments are performed on AISI 1020 carbon steel workpieces and the stability conditions are found to be in good agreement.