A tooth-by-tooth dynamic redistribution model for the prediction of milling-induced residual stress

Existing milling residual stress models usually assume a static stress state following material removal and fail to account for the dynamic stress evolution that occurs on a tooth-by-tooth basis during milling. In fact, cutting actions associated with successive tooth cycles continuously disturb the stress equilibrium through coupled mechanisms of stress release, redistribution, and thermo–mechanical interactions, significantly impacting the final residual stress distribution. To address this limitation, this study proposes a model for predicting milling-induced residual stresses by effectively considering the dynamic redistribution occurring between individual cutter tooth cycles. Stress equilibrium relations at actual milling instants are established by comprehensively accounting for the initial workpiece stress state, as well as the coupling relationships among workpiece deformation, stresses in the removed material area, and newly generated stresses, based on moment balance conditions and a validated milling residual stress model. This model combines the time-varying stresses generated during the tooth-by-tooth material removal process with the initial residual stresses, thereby providing a precise depiction of how stresses evolve at different cutting instants under the combined influences of material removal and thermo–mechanical loading. Blind-hole method measurements, milling tests, and finite element simulations are performed on titanium alloy Ti6Al4V and aluminum alloy 7075 components, and good agreement between the predicted and measured residual stresses and their induced deformations confirm the correctness and reliability of the proposed model.