Initial residual stress measurement based on piecewise calculation methods for predicting machining deformation of aeronautical monolithic components

摘要

Release and rebalance of initial residual stress of pre-stretched aluminum alloy plates in processing is the main factor affecting the machining deformation of aeronautic monolithic components. Precision measurement of the initial residual stress is of great significance for predicting and controlling the machining deformation. In this paper, two piecewise calculation methods for calculating the initial residual stress were presented. A test method based on superposition principle of elastic deformation was proposed to calculate the residual stress in the outer layer. Another method to calculate residual stress in the outer layer was crack compliance method using frontal strain instead of back strain. Then, the residual stress in the inner layer was calculated by the crack compliance method, and the influence of the order of interpolation polynomials on the results was studied. The accuracy of the two new methods were verified by finite element simulation and machining experiments. Considering only the initial residual stress, a relatively higher prediction accuracy of machining deformation can be obtained.