Numerical Analysis on Stress Evolution During GTA-Additive Manufacturing of Thin-Walled Aluminum Alloys

GTA-Additive Manufacturing (GTA-AM) is one of the Wire Arc Additive Manufacturing (WAAM) technologies based on Gas Tungsten Arc Welding (GTAW). During the GTA-AM process, non-uniform heating, as well as rapid heating and cooling of deposited materials lead to inevitable temperature stress, while repeated remelting in subsequent deposition introduces complexity to the evolution of it. Finite element modeling was conducted in this work to investigate the stress evolution during the GTA-AM of thin-walled 5183-Al. Several thin-walled 5183-Al components with different bead widths are included to understand the influences brought about by geometry dimensions. Hole-drilling method is used to measure the residual stress of 5183-Al components manufactured by GTA-AM, which proves the reliability of this numerical model. Results of modeling show that the temperature stress is generated and released alternately and repeatedly as the deposition proceeds. The cycles of equivalent stress are in synchronization with the thermal cycles, in which equivalent stress reaches peak when temperature gets to its valley value. However, as the deposition layers pile up, the peak value of equivalent stress decreases gradually, and finally achieves stability after a certain layer. As for the influences of geometry dimensions, larger bead width results in higher level of stress due to much larger heat input as well as grater constraints. (paper)