Date of Award

5-2007

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Mechanical Engineering

Advisor

Fadel, Georges M

Abstract

Ultrasonic Consolidation is a combination of additive and subtractive
manufacturing processes resulting in considerable material waste. This waste is a
function of the geometry of the part being manufactured and of the relative
placement of the layer with respect to the metal bands. Thus the waste may be
minimized by careful choice of the layer angle and offset from the original
position.
Previous work done in this field had developed an automated algorithm which
optimally places and orients the individual slices of the STL file of the artifact
being manufactured. However, the problem was solved on a 2-D scale and the 3-
D nature of the part was not considered for the development of the algorithm. The
earlier algorithm employed approximation on the input data to minimize the
computational expense. This resulted in convergence of the optimizer to suboptimal
solutions. Further, as the final part is made of anisotropic material the
relative angles and overlap between subsequent layers also plays an important
role in the final part strength. Finally, it is noted that the build time required for
the ultrasonic consolidation process is a function of the number of bands required
to form each slice.
Considering these limitations and opportunities, this thesis presents an algorithm
which optimally orients and places the part layers with respect to aluminum bands
in order to minimize the waste formed and the build time required. The algorithm
has the capability of increasing the part strength by forming crisscross and brick
structures using the metal foils. This research work also improves on the previous
algorithm by extending the functionality of the algorithm by building in capability
to handle multiple loops within the same slice and non convex slice data. Further,
the research studies the choice of optimizer that needs to be employed for
different types of input data.

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