Design and Analysis of Additively Manufactured Components with Integrated Lattice Structures
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Examensarbete för masterexamen
Modellbyggare
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Volymtitel
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Sammanfattning
Additive Manufacturing (AM) for metals is a fast growing field which is almost ready
for industrialisation. Structural optimisation(SO) tools like Topology optimisation(TO)
are now the most beneficial tools to the area of structural design. But, these tools give
a design output that is very difficult to be manufactured by conventional manufacturing
techniques like casting. This is where AM comes into the picture as it helps to overcome
the rigid boundaries of other manufacturing methods due to its ability in helping produce
objects of complex shapes and functionality. Lattice structures are very useful elements
in structural design but are very difficult to produce by other methods , especially for the
purpose as infill for objects. This gives an opportunity to use AM for producing objects
with integrated lattice structure.
The are various types of lattice structures like octet, gyroid etc. By properly aligning
the lattice structure inside an object instead of completely filling it, structures with low
density and weight can be achieved while also being strong. Lattice structures have been
used as temporary support material for AM prints, but here they will also be a part of the
final component itself serving as functional structures. This master thesis conducted at
RISE IVF consists of first studying various types of self-supporting lattices and conducting
virtual tests with regard to shear, tension, compression stresses etc. The second part of
the thesis concerns topology optimization of a structural component design provided by
Volvo Cars. This is done in order to get a design output that is suitable to be integrated
with lattice structure to achieve lightweighting with minimal changes to the strength
characteristics. A homogenized model is developed to verify the effects of the lattice unit
cell in the optimized component.
The final results of the linear analysis of the homogenized model was compared to the
linear analysis of the steel sheet metal pivot bracket given by Volvo Cars. The final result
comparison and analysis showed that the topology optimized pivot bracket component
with integrated lattice structure was slightly lighter than the steel sheet metal pivot
bracket designed by Volvo Cars and of comparable stiffness. This methodology allowed
the authors to create a component design that is integrated with lattice structure and
has a comparative stiffness design parameter of the original component. The design is
also potentially manufacturable by AM, but the time limit prevented the actual printing
process and hence all results were verified virtually. This methodology can be used for
components that are fit for manufacturing via additive manufacturing for the purpose of
lightweighting without much loss of structural integrity.
Beskrivning
Ämne/nyckelord
Unit Lattice Cell, Topology Optimisation, Lattice Optimisation, Homogenisation, Additive Manufacturing