SUMMARY

Laser powder bed fusion additive manufacturing offers enormous potential for the creation of unique and complex geometries such as lattice structures, which are favored for their high stiffness- and strength-to-weight ratios, energy absorption capacity, and functionally gradable properties. Despite this potential, the thousands to millions of sub-millimeter sized features in lattices create challenges for their manufacture, inspection, and reliability. To address these challenges, the role of manufacturability in determining the performance and failure responses of lattices is investigated in this dissertation. A high-throughput geometry characterization methodology was developed using computed tomography (CT) and advanced image processing for the creation of models relating manufacturing variables to strut geometry. The resulting models provided insight into the physical phenomena governing these relationships and were used to identify methods for manufacturability improvement. Then, full-size octahedron lattices were manufactured across a range of laser powers, dimensionally characterized, and assessed for compressive performance properties. Models were developed from this data which providing a deepened understand of the role of manufacturability in determining lattice performance. Design influences were then studied through the addition of nodal fillets to exemplar bending- and stretching-dominated designs. In-situ CT-mechanical testing was utilized to reveal the mechanisms through which these design modifications determine lattice failure response, and the different effects fillets have on these varying lattice designs. Together, these studies form a comprehensive assessment approach and understanding of the manufacturability, design, and failure of additively manufactured lattices.