Prediction Model for the Evolution of Residual Stresses and Machining Deformation of Uneven Milling Plate Blanks

Abstract

During aerospace thin-walled component processing, the prediction and control of machining deformation have gained increasing attention. The initial residual stress in the blank is a major factor leading to the occurrence of machining deformation. This paper proposes the concept of uneven milling during the workpiece machining process, which is caused by the variation in local cutting depth resulting in uneven material removal thickness. Based on the elasticity theory, an analytical model is established to predict the evolution of overall residual stress and machining deformation in beam-like aluminum alloy components under uneven milling conditions. The effectiveness of the model is verified through finite element simulations and experiments. The results are as follows: (1) Under uneven milling conditions, the analytical model can accurately predict the distribution of residual stress and the machining deformation within the ZX section of the workpiece. (2) The uneven distribution of bending stress arises from the different curvature radii of various positions after workpiece deformation, leading to a 1 MPa to 3 MPa difference in stress between the middle and both ends of the workpiece. (3) During the layer-by-layer milling process, the magnitude of workpiece deformation is related to the stress state of the material removed, and there is a deformation superposition effect on the lower surface of the workpiece, further exacerbating the overall machining deformation.

Semi-Analytical Solution Model for Bending Deformation of T-Shaped Aviation Aluminium Alloy Components under Residual Stress

“…It becomes apparent that the relationship between the plate dimension ratio (W/L) and deflection values is not linear. The data from Table 5 were fitted using MAT-LAB (the version used in the study is matlab2013a) to derive formulas for calculating deflection values, presented as Equations ( 13) and (14). Equation ( 13) represents the formula for calculating deflection values under the influence of M x = 100 N•m and M y = −198 N•m, while Equation ( 14) for the influence of M x = 100 N•m and M y = 198 N•m.…”

“…Conducting finite element analysis, Li et al modelled the layered milling of straight-face micro-thin-walled features with varying thicknesses to explore deformation patterns along the height and length of thin walls [13]. By adjusting the milling depth, Zheng et al explored the machining deformation and stress distribution patterns under different cutting thicknesses, proposing a predictive model for machining deformation under varied milling conditions based on the theory of elastic deformation [14]. Zhu et al considered both initial residual stresses and the operational loads on workpieces, creating a comprehensive model that includes equilibrium equations and stress boundary conditions through finite element methods to predict the resulting deformation in workpieces [15].…”