Stress in Thin Wall Structures Made by Layer Additive Manufacturing

Abstract

Abstract. Manufacturing of thin wall structures is one of the main applications of additive manufacturing, where it has significant advantages over traditional milling and machining techniques or welded analogues. Such thin walled structures are common in structural aerospace components, and are also frequently made from titanium alloys. For such large-scale components, layer deposition strategy is more advantageous rather than a pixel-wise deposition approach due to the demand for high productivity and size requirements. Several techniques can be used to produce layer-wise buildups, including laser-powered Direct Metal Deposition (DMD) process or gas tungsten arc welding (GTAW). Although, in the general case of arbitrary thin wall structures the stress distribution is complex, for some simple geometries, the stress state is simple and can be well characterized within a model by a single parameter representing a layer deposition stress in the steady-state regime. The model calculations were verified by experimental results on a thin-walled sample component that was manufactured from Ti-6Al-4V by GTAW with the residual stresses measured using KOWARI neutron strain scanner at the OPAL research reactor (ANSTO).

Digital Image Correlation for Measuring Full-Field Residual Stresses in Wire and Arc Additive Manufactured Components

“…Localised heating and uneven cooling during the WAAM process introduce large thermal gradients causing distortion and residual stresses, which can affect the topology and global integrity of a WAAM component [ 3 ]. In the last decade, WAAM induced residual stresses have been experimentally investigated for various alloys, such as steel [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ], aluminium [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ], titanium [ 3 , 13 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ], nickel [ 13 , 29 , 31 , 32 , 33 ], intermetallics [ 21 , 34 , 35 ], etc. The aforementioned literature has focused on quite a few areas including but not limited to the effect of process and geometrical variables on residual stresses, the effect of interpass and side rolling on controlling/reducing residual stresses, and the effect of pre-and post-processing on residual stresses, etc.…”

Fabrication of Thin Walls with and without Close Loop Control as a Function of Scan Strategy Via Direct Energy Deposition

“…Thin-walled structures are common in aerospace, automotive and many other sectors and is one of the main applications of Additive Manufacturing (AM). The fabrication of such thin-walled structures is quite challenging due to complex stress distribution [5]. Also, it is often of interest to know the smallest possible feature which is geometrically consistent to be manufactured by DED [6].…”