A unified bond-based peridynamic framework for welding residual-stress analysis with process-generated weld geometry and transformation-induced volumetric strain

A unified bond-based peridynamic framework is developed for welding residual-stress analysis with process-generated weld geometry and transformation-induced volumetric strain. Filler material is represented by material points that undergo melting, gravity-driven redistribution, resolidification, and stress-free bond reconstruction. The formulation couples transient heat conduction, apparent-heat-capacity latent-heat treatment, solid–liquid switching, mushy-zone stiffness degradation, thermal and transformation eigenstrains, and committed incremental J 2 plasticity. The fixed-geometry thermal–mechanical branch is assessed against the thermo-elasto-plastic finite element results of Deng and Murakawa, reproducing the characteristic tensile–compressive–recovery residual-stress profile with a correlation coefficient of 0.933 and R 2 of 0.868. In the process-generated examples, a prescribed 1% volumetric transformation strain reduces the maximum displacement and equivalent plastic strain by 5.12% and 5.01%, respectively, while redistributing residual stress. An energy-matched heat-input perturbation changes the number of resolidified filler points from 54 to 61 and direct filler–base bonds from 13 to 29, demonstrating that equal total heat input does not uniquely determine the melt/reconstruction history or final load-carrying topology. The fully cooled final states satisfy the adopted constitutive and equilibrium criteria. The framework provides a mechanics-oriented basis for coupling evolving weld geometry, topology reconstruction, transformation strain, and residual stress, while not resolving full weld-pool hydrodynamics or transformation plasticity.