Applied Mechanics Commons^™

An Efficient Computational Frameworks For Design And Analysis Of Metamaterials, Raj Pradip Khawale

All Dissertations

Advancement in additive manufacturing helps in building artificial lattice structures with unique properties that are not available in naturally occurring materials or in continuum structures. Specifically, beam-based lattices are well known for producing lightweight structures with very high strength, auxetic behavior, and energy absorption capabilities. In recent years, numerous research studies have been conducted on generating algorithms and frameworks to obtain unusual properties based on the variation in the cell geometry and material properties. However, the exploration of the full design space is hampered in practice primarily due to restrictions on cell tiling variation. Additionally, the lattices are very intricate, …

Novel Vector Assignment Approach For Inherent Strain Modeling Of Laser Powder Bed Fusion Manufacturing, Lucas M. Morand

All Dissertations

The expansion of the design space due to additive manufacturing (AM) has been a large motivator for the success of this family of processes. Despite the complexity of the physics in metal laser powder bed fusion AM causing significant stresses and strains in finished parts, the design advantages and subsequent performance improvements continue to drive the expansion of AM. Because the trial-and-error approach to AM part development is cost prohibitive, simulation of prints has become crucial. However, full thermo-mechanical simulation is susceptible to the same pitfall of time and computational cost in order to attain part-scale results. The development of …

Experimental Investigations And Optimization Of 3d Printed Cellular Structures For Protection Against Traumatic Brain Injury, Aaron R. Jackson

Mechanical and Aerospace Engineering Dissertations - Archive

Traumatic Brain Injury (TBI) disrupts brain function due to head impacts, blast exposures, and ballistic penetrations. It is a significant cause of mental health issues and disability, particularly among military personnel. Historically, combat helmets were designed primarily to protect against fragments. However, recent data highlights the need for helmets that also protect against blast and blunt impacts. Effective TBI prevention requires helmets that address various energy threats while remaining lightweight. A critical metric in this effort is head acceleration, which is closely linked to injury across different scales of brain damage.

Four lattice structures were 3D printed using Digital ABS …

In-Situ Tribology Of Engineered Surfaces With 3d-Printed Micro/Nano-Textures, Mahyar Afshar Mohajer

Graduate Theses and Dissertations

Surface texturing is an effective way to reduce the adhesion and friction between two contacting surfaces by reducing the real area of contact between them, providing a potential solution for adhesion and friction-induced failures, for example, failures in micro-/nano-electromechanical systems (MEMS/NEMS). Surface texturing is also essential to the realization of functional surfaces such as superhydrophobic/philic and icephobic surfaces. However, textures are prone to deformation due to being subjected to higher contact pressures. The advancement of 3D nanoprinting by two-photon lithography (TPL), combined with the ability to make an in-situ observation of the interplay between the forces and the sliding surfaces …

The Temperature Dependent Mechanical Response Of M250 Maraging Steel And Its Implications On Wire Arc Additive Manufacturing, Frank M. Brinkley Iii

Theses and Dissertations

Wire-arc additive manufacturing (WAAM) is becoming increasingly common for large scale additive manufacturing (AM) applications because of its high deposition rate (2-3 kg/hr.). The rapid temperature changes and subsequent evolution of mechanical properties during AM can lead to large distortion and residual stresses. Finite element modeling of the AM process shows promise to minimize part distortion and residual stresses through improved path planning and process parameter optimization. However, accurate material properties of M250 before and after heat treatment are needed to properly characterize the property evolution from annealed to AM, to aged. Due to limited data on annealed M250, this …

Autonomous Material Refill For Swarm 3d Printing, William C. Jones

Mechanical Engineering Undergraduate Honors Theses

3D printing currently offers robust and cheap rapid prototyping solutions. While standard 3D printing remains at the periphery of mass production, the technology serves as a starting point for the development of swarm manufacturing. Since swarm manufacturing is predicated upon autonomy, swarm technology companies such as AMBOTS are seeking to minimize human involvement in the swarm’s functions. At present, the 3D printing swarm consists of the printers, a transporter which can take them between job sites, and the floor tiles which provide power and support the build surfaces. To add to this ecosystem, this project is focused on the design …

Design, Fabrication, And Reliability Effects Of Additively Manufactured First Level Compliant Interconnects For Microelectronics Application, Tumininu David Olatunji

Graduate Theses and Dissertations

Semiconductor packaging and development is greatly dependent on the magnitude of interconnect and on-chip stress that ultimately limits the reliability of electronic components. Thermomechanical related strains occur because of the coefficient of thermal expansion mismatch from different conjoined materials being assembled to manufacture a device. To curb the effect of thermal expansion mismatch between conjoined parts, studies have been done in integrating compliant structures between dies, solder balls, and substrates. Initial studies have enabled the design and manufacturing of these structures using a photolithography approach which involves a high number of fabrication steps depending on the complexity of the structures …

Microheater Array Powder Sintering (Maps) For Printing Flexible Electronics, Nicholas Holt

Graduate Theses and Dissertations

Microheater array powder sintering (MAPS) is a novel additive manufacturing process that uses an array of microheaters to selectively sinter powder particles. MAPS shows great promise as a new method of printing flexible electronics by enabling digital curing of conductive inks on a variety of substrates. MAPS operation relies on establishing a precision air gap of a few microns between an array of microheaters, which can reach temperatures of 600°C, and a layer of conductive ink which can be deposited onto a flexible substrate. This system presents challenges, being: the fabrication of a microheater that can reach suitable temperatures in …