Numerical Assessments of Cyclic Plastic Deformation and Strain Gradients in Dissimilar Metal Welds

The present work is aimed at numerical assessment of dissimilar metal welds under pure axial and pure torsion cyclic loading conditions. Finite element analyses have been performed to quantify the strain gradient on hot-wire narrow-groove DMWs of SA508 Gr.3 Cl.1 and SS304LN with SS308L filler material. The elastic plastic finite element analyses have been performed using three-decomposed Chaboche material models of these segments (two parent materials and one weld material). The remote strain is controlled to attain maximum total von-Mises equivalent strain amplitudes of 1%, 0.75%, 0.5%, and 0.35% in the gauge region of weldment. The quantifications of strain gradients under different strain amplitudes and remote loading conditions have been performed in radial and axial directions. Fatigue life estimation is performed for different equivalent strain amplitudes, utilizing material specific strain-life equations.