Eigenstrain Reconstruction of Residual Stress for Thermo-Chemical Surface Treatment in Arbitrary 3D Geometries

A modified procedure is presented to reconstruct the residual stress fields obtained from surface treatments in arbitrary three-dimensional geometries by employing the eigenstrain method based on the finite element (FE) method and is implemented through the ANSYS APDL scripts. Initially, the finite element data is collected and then the related distance and orientation computation is carried out using the ANSYS APDL script. This method is proven to be insensitive to the complexity of the curvature treated surface and able to decrease the related errors caused by the differentiation operations during the use of Wall's distance module in COMSOL within the previous works of literature. In this work, a thermo-chemical treatment of notched component obtained from the literature is analyzed, followed by validation of the presented methodology and its efficiency to rebuild the residual stress fields for complex geometry in a thermochemical treatment case. The suggested framework is a general and versatile solution to introduce the eigenstrain method into complex geometries through FEA software for the design of industrial applications.