A multiscale methodology for deformation modeling applied to friction stir welded steel

This paper presents a multiscale simulation methodology for the study of texture and residual strain development applied to deformation of friction stir welded material and includes a coordinated experimental program for model initialization and verification. Based on elastoviscoplastic polycrystal plasticity implemented in a finite element framework, the simulation methodology involves detailed tracking of selected elements in a relatively coarse macroscopic model followed by highly resolved simulations of the selected elements at the microscopic level. The results are compared with neutron diffraction data obtained by subjecting friction stir welded specimens to a program of in situ loadings and unloadings. The model performs well for three different specimen geometries—both at the macroscopic level in predicting deformed shape, hardness and extension, and at the microscopic level in predicting lattice strain and intensity changes.