D.H. Lammlein PhD Dissertation - Vanderbilt University

Figure 51: A thermal camera image taken during the steady state weld period of a
1000rpm, 4 ipm, blind-T weld
Model Geometry
Two model geometries were creating representing a centered tool case and an
offset case of 0.05 inches to the advancing and retreating side. The tool rotation is varied
in the latter to simulate offsets to the retreating and to the advancing side of the weld.
The mesh was created in a mesh generation and preprocessing program called Gambit.
The model was divided into several continuum zones to account for material type. The
models contain approximately 960,000 tetrahedral elements. The work material has been
divided into a refined zone of plastic aluminum behavior around the tool and zones of
solid aluminum and steel behavior away from the tool where only heat conduction
equations are solved. The zone immediately in front and the zone immediately behind
the central refined zone are also modeled using a plastic aluminum formulation to create
a stabilized flow into and out of the zone of interest around the tool. A velocity inlet set
to the traverse rate and an outflow boundary condition are used to establish a relative
velocity between the tool and workpiece.
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