Surface stress distribution of thin-walled spherical pure iron component after turning process

Abstract

There is still gap for predicting the residual stress distribution of machined surface for curved components effectively in academic research. In order to obtain the spatial distribution of surface residual stress for such workpieces, a new approach which considering three-dimensional (3D) finite element (FE) model at sample points and corresponding mapping techniques is proposed. The machining of curved component is equivalent to turning of a series of continuous points. According to the idea of discrete method, regular cutting positions are chosen. A 3D FE model is then established for predicting residual stress profile in these fixed turning positions according to the real cutting parameters. These simulated stress profiles act as the given information for stress field construction. For any point in the stress layer area, the stresses are acquired by using linear interpolation of the stress information and then transformed into the global system. Relevant mathematical algorithms are developed for mapping predicted residual stresses into the target component by secondary development of the Abaqus software. Its innovation lies in that the non-uniformity of spatial stress field which is caused by changing machining-parameters and tool-workpiece contact is modeled. The spatial distribution of surface stresses for a turned spherical component made of pure iron are given as an example and analyzed in detail. The analysis shows that cutting and feeding stresses on the spherical surface first increase rapidly, then slowly increase along the generatrix. Moreover, predicted residual stresses are in accordance with the X-ray diffraction measured ones, which confirms the reliability of the developed model to predict stress distribution of curved components after turning process.