Residual stress prediction for laser powder bed fusion parts: a critical assessment of inherent strain and block dump modelling strategies

Metal additive manufacturing, particularly laser powder bed fusion (LPBF), offers major advantages in design flexibility and near-net-shape production. However, the steep thermal gradients inherent to the process generate high residual stresses that can lead to distortion or cracking, thereby compromising part integrity. Conventional optimisation of process parameters through trial-and-error experimentation is costly and time-consuming, underscoring the need for reliable modelling strategies. In this study, two part-scale simulation approaches, the inherent strain method and the block dump method, were systematically evaluated for residual stress prediction in LPBF of Hastelloy X. Representative finite element implementations were developed and benchmarked against experimental observations, including cantilever deflections and residual stress fields obtained from neutron diffraction. Both methods captured the experimental trends with good overall consistency. The block dump method achieved slightly higher accuracy without requiring calibration, but at the expense of increased computational cost and reliance on a more comprehensive set of material input data, including temperature-dependent thermal and mechanical material properties. Sensitivity analyses further showed that predictions from the inherent strain method are highly dependent on the calibration of the inherent strain tensor, whereas the block dump method is more robust with respect to modelling assumptions. Finally, the results of this study indicate that while both strategies offer practical predictive capability, the block dump method provides better generalisation capability for residual stress prediction in LPBF components.