Engineering Commons^™

Hydrokinetic Turbine Composite Blades And Sandwich Structures: Damage Evaluation And Numerical Simulation, Mokhtar Fal

Doctoral Dissertations

“Composite materials are gaining interest due to their high strength to weight ratio. This study deals with both experimental and numerical approaches to cover the aspects of the failure of composite materials in hydrokinetic turbine applications. In Part I, the location and magnitude of failure in the horizontal axis water turbine carbon fiber-reinforced polymer (CFRP) composite blades with different laminate stacking sequences were investigated. Two lay-up orientations were adopted for this work ([0⁰]₄ and [0⁰/90⁰]_2s). A finite element analysis model was generated to examine the stresses along the blade. Five angles were introduced to study the effect …

Performance Evaluation Of Alsi10mg Fabricated By A Selective Laser Melting Process, David Michael Murphy

Masters Theses

“Selective laser melting is becoming a widely used additive manufacturing technique that melts metal powder in a layer by layer process in order to build a desired part or geometry. Like many additive processes, selective laser melting allows for fabrication of parts with complex geometries. In order to fabricate a fully dense part there are a number of variables to take into account including: powder characteristics, laser parameters, and environmental parameters. Each of these variables can affect the microstructure and thus the mechanical performance of an additively manufactured part. In this work, the aluminum alloy AlSi10Mg was investigated. AlSi10Mg is …

3d Printing Reinforced Concrete Structures, Bryce Tyler Tafolla

Masters Theses

"This study aims to investigate a 3D printing method to directly incorporate continuous reinforcement into concrete structures. The ability to design and produce complex structures with optimized topographical configuration can be used to reduce potential material waste while maintaining the required structural strength. Furthermore, the ability to actively incorporate reinforcement into printed members substantially reduces potential labor requirements and eliminates the need to set up formwork.

The study began its initial approach with a manual extrusion process containing reinforcement to observe the necessary constraints required to achieve a printing system with this functionality. The second stage of development was designing …

Influence Of Input Energy On Mechanical Properties Of Laser Powder Bed Fused Aisi 304l Stainless Steel, Tan Pan

Masters Theses

“Powder Bed Fusion process with selective laser melting technique is popularly adopted in additive manufacturing area on account of its layer by layer manufacturing fashion capable of fabricating components with complex internal and external geometries and structures. However, the process-property map is unique and vital for different materials and AM configurations used for fabrication. The process parameter is identified as a significant factor that heavily influences the properties and performances of the printed materials.

Current work aimed to extend the existing knowledge on Laser Powder Bed Fusion fabricated AISI 304L by accessing the influence of varying energy input on the …

Additive Manufacturing Of Customized Lithium-Ion Batteries: Process Fundamentals And Applications, Xiaowei Yu

Doctoral Dissertations

“In the pasting decades, considerable efforts have been spent in developing the next-generation lithium-ion batteries (LIBs), from advanced active materials to new manufacturing methods. The development of additive manufacturing (AM) has brought new opportunities to LIBs. In this work, two AM methods are introduced for fabricating electrodes of LIBs. The first method is aerosol printing, which is a solvent-based wet additive method. Whereas the second method is a solvent-free, dry printing method. The commonly used materials for current collectors and active materials (including cathodes and anodes) of LIBs are aerosol printed and the electrochemical functionalities of the printed materials are …

A Framework For A Successful Additive Repair System, Todd E. Sparks

Doctoral Dissertations

“The goal of this research is to generate a revolutionary improvement to the usability and usefulness of additive repair technology by integrating a set of tools into a seamless work flow. Insufficient automation in the current repair process is a huge hurdle in achieving cost-effective, reliable repairs. Many opportunities have been missed due to inconsistency, quality issues and lack of robustness and flexibility. The present work addresses deficiencies in preparatory steps such as 2D and 3D geometry processing, parameter estimation, and path planning as well as on-machine execution of the path plan. The bulk of the effort is focused on …

Development Of Lightweight Materials By Meso- And Microstructure Control, Myranda Shea Spratt

Doctoral Dissertations

”In this work, two lightweight structures – lattice structures and metal matrix syntactic foams (MMSF) – were studied. Honeycomb lattices were manufactured by powder bed selective laser melting (SLM) from 304L stainless steel. The wall thicknesses of these structures ranged from 0.2 to 0.5 mm. Surface roughness was the primary cause of dimensional mismatch between the expected and as-built structures with an average wall thickness increase of 0.12 mm. The strength of the honeycombs increased with increasing wall thickness. A feature of the SLM microstructure, the melt pool boundary, was also studied as a part of this work. 3D models …