Residual stresses have been identified as one of the biggest challenges in each Directed Energy Deposition process (DED). Residual stresses can significantly affect the dimensional accuracy, mechanical performance, and service life of additively manufactured components. This study develops and validates a three-dimensional thermo–mechanical finite element model to predict residual stresses in a thin wall component fabricated by DED of 316 L stainless steel. The model employs Goldak’s double-ellipsoid heat source, element activation (birth) technique, and temperature-dependent material properties. Validation of model predictions was done by comparing with experimental values for residual stresses measured using X-ray diffraction, which showed good matching between model predictions and experimental values. Full factorial Design of Experiments was used with process variables such as laser power, dwell time, and baseplate thickness. Analysis of variance showed that baseplate thickness is a significant parameter that significantly affects residual stresses. The optimized variables resulted in about 45% reduction in tensile residual stresses compared to the original situation.
Turki et al. (Mon,) studied this question.