2022/05/16 by Will Yeadon, Yeadon, Will
Engineering · Mathematics · Physics and Astronomy · #Arc welding #Composite material #Computer science #Engineering #FOS: Physical sciences #Finite element method #Fluid Dynamics (physics.flu-dyn) #Gas Dynamics and Kinetic Theory #Gas tungsten arc welding #High Energy Physics - Experiment (hep-ex) #Materials science #Mechanical engineering #Mechanics #Metallurgy #Multiphysics #Physics #Solver #Structural engineering #Titanium #Tube (container) #Vacuum and Plasma Arcs #Weld pool #Welding #Welding Techniques and Residual Stresses #hep-ex #physics.flu-dyn
paper · pdf · doi:10.48550/arxiv.2205.07687
published in arXiv (Cornell University) (Cornell University) · Final PhD thesis on ATLAS cooling system joinery. 218 Pages, 95 figures
arxiv created 2022/05/16 · openalex publication_date 2022/05/16 · arxiv updated 2022/05/17 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
This thesis presents a novel multiphysics solver, named gtawFoam, for Gas Tungsten Arc Welding (GTAW) that is applied to simulate orbital GTAW on ultra-thin-walled titanium tubing. In this thesis, ultra-thin-walled tubing refers to tubing where the wall thicknesses are less than 500 μm. Orbital welding of tubing with this wall thickness requires both a sufficient heat input to weld the tubing and an internal buttressing gas flow to ensure the tube retains its geometrical integrity. The specific use case is for the commercially pure grade 2 titanium tubing used in the ATLAS ITk cooling system which is 2.275 mm outer diameter and 300 μm wall thickness at the weld. The solver is created using the open source computational fluid dynamics library OpenFOAM and each component of the solver is benchmarked against an appropriate case. With the solver established, it is used to simulate a series of welding procedures that were performed experimentally on the aforementioned titanium tubing. Both the experimental and simulation results show a `goldilocks' region where the weld heat input and inner buttressing gas flow are moderated to a level where a fully penetrating weld is created but the geometric integrity of the tube is not compromised. gtawFoam is then used to simulate hypothetical tubing with larger and smaller wall thicknesses between 250 μm and 350 μm. The results suggest that the required buttressing gas pressure once achieved is relatively transferable between wall thickness changes but applying enough heat so as to achieve full penetration is critical. These results are then used to predict effective welding procedures for this hypothetical tubing. gtawFoam is subsequently applied to the welding of turbine blades. This includes the addition of multiple layers of filler metal to mimic additive manufacturing.