Manufacturing Commons^™

Shape Memory Behavior Of Dense And Porous Niti Alloys Fabricated By Selective Laser Melting, Soheil Saedi

Theses and Dissertations--Mechanical and Aerospace Engineering

Selective Laser Melting (SLM) of Additive Manufacturing is an attractive fabrication method that employs CAD data to selectively melt the metal powder layer by layer via a laser beam and produce a 3D part. This method not only opens a new window in overcoming traditional NiTi fabrication problems but also for producing porous or complex shaped structures. The combination of SLM fabrication advantages with the unique properties of NiTi alloys, such as shape memory effect, superelasticity, high ductility, work output, corrosion, biocompatibility, etc. makes SLM NiTi alloys extremely promising for numerous applications.

The SLM process parameters such as laser power, …

Torque Response Of Thin-Film Ferromagnetic Prisms In Uniform Magnetic Fields At Macro And Micro Scales, Soroosh Torabi

Theses and Dissertations--Mechanical and Aerospace Engineering

The non-contact nature of magnetic actuation makes it useful in a variety of microscale applications, from microfluidics and lab-on-a-chip devices to classical MEMS or even microrobotics. Ferromagnetic materials like nickel are particularly attractive, because they can be easily deposited and patterned using traditional lithography-based microscale fabrication methods. However, the response of ferromagnetic materials in a magnetic field can be difficult to predict. When placed in a magnetic field, high magnetization is induced in these ferromagnetic materials, which in turn generates force and/or torque on the ferromagnetic bodies. The magnitude and direction of these forces are highly dependent on the type …

A Framework And Metrics For Sustainable Manufacturing Performance Evaluation At The Production Line, Plant And Enterprise Levels, Aihua Huang

Theses and Dissertations--Mechanical and Aerospace Engineering

Sustainable manufacturing is becoming increasingly important due to scarcity of natural resources, stricter regulations and increasing customer demand for sustainable products. Sustainable manufacturing involves the use of sustainable processes and systems to produce more sustainable products. In order to meet these demands for sustainable products, manufacturing companies have to adopt numerous strategies to achieve sustainable manufacturing. The approach for evaluating sustainable products and processes have been investigated in previous work where product/process sustainability indices were proposed. However, no comprehensive methods are available for sustainable manufacturing performance evaluation at the system level. This work aims to develop two alternate methods for …

Development Of A Supplier Segmentation Method For Increased Resilience And Robustness: A Study Using Agent Based Modeling And Simulation, Adam J. Brown

Theses and Dissertations--Mechanical and Aerospace Engineering

Supply chain management is a complex process requiring the coordination of numerous decisions in the attempt to balance often-conflicting objectives such as quality, cost, and on-time delivery. To meet these and other objectives, a focal company must develop organized systems for establishing and managing its supplier relationships. A reliable, decision-support tool is needed for selecting the best procurement strategy for each supplier, given knowledge of the existing sourcing environment. Supplier segmentation is a well-established and resource-efficient tool used to identify procurement strategies for groups of suppliers with similar characteristics. However, the existing methods of segmentation generally select strategies that optimize …

Investigation Of Polishing Methods And Surface Analysis After Machining Aisi 4140 Alloy Steel, Qiang Qi

Theses and Dissertations--Mechanical and Aerospace Engineering

AISI 4140 alloy steel has been a very common material to be investigated in automotive and aerospace industries for several decades. AISI 4140 alloy steel is chromium, molybdenum, and manganese containing low alloy steel. It has high fatigue strength, abrasion and impact resistance, toughness, and torsional strength. The functional performance is largely determined by the surface states after machining.

The aim of the present study is to explore the polishing methods and surface analysis after machining AISI 4140 alloy steel in different cutting speeds and cooling conditions. The surface analysis includes surface roughness, hardness and residual stresses. Compared to traditional …

Product Disassemblability And Remanufacturability Assessment: A Quantitative Approach, Ammar Ali

Theses and Dissertations--Mechanical and Aerospace Engineering

Majority of the products get discarded at end-of-life (EoL), causing environmental pollution, and resulting in a complete loss of all materials and embodied energy. Adopting a closed-loop material flow approach can aid preventing such losses and enable EoL value recovery from these products. Design and engineering decisions made and how products are used impact the capability to implement EOL strategies such as disassembly and remanufacturing. Some underlying factors affecting the capability to implement these EOL strategies have been discussed in previous studies. However, relevant metrics and attributes are not well defined and comprehensive methods to quantitatively evaluate them are lacking. …

Energy Resources Use Metrics, Rahul Y. Nehete

Theses and Dissertations--Mechanical and Aerospace Engineering

Energy resources use has been considered as a key component of sustainable development. Data related to global, regional, state, sector, industry and process demonstrate that a significant reduction of energy resources for a given production rate in manufacturing processes requires an introduction of transformational technologies at the process level, propagating the impact to higher scales, leading not just to a gradual improvement of traditional technologies but to more sustainable development.

The study offers two approaches to the formulation of the limits of energy use in the context of sustainable development. The first is to construct a map of key selected …

Cryogenic Processing Of Al 7050-T7451 Alloy For Improved Surface Integrity, Bo Huang

Theses and Dissertations--Mechanical and Aerospace Engineering

Al 7050-T7451 alloy with good combinations of strength, stress corrosion cracking resistance and toughness, is used broadly in the aerospace/aviation industry for fatigue-critical airframe structural components. However, it is also considered as a highly anisotropic alloy as the crack growth behavior along the short transverse direction is very different from the one in the long transverse direction, due to the inhomogeneous microstructure with the elongated grains distributed in the work material used in the sheet/plate applications. Further processes on these materials are needed to improve its mechanical and material properties and broaden its applications.

The material with ultra-fine or nano …

Effect Of Heating And Ionization Of Four Atomizing Gases On The Spray Characteristics Of A High Volume Low Pressure Spray Atomizer, Anthony V. Adornato

Theses and Dissertations--Mechanical and Aerospace Engineering

The disintegration of a liquid jet emerging from a nozzle by a high speed gas stream has been under investigation of several decades. A result of the liquid jet disintegration is droplet formation. This process is referred to as atomization. Industrial applications use atomization as a method for applying coatings to substrates. It has been reported that the use of other atomizing gases instead of compressed plant air will positively affect paint droplet size distributions, spray patterns and finish qualities; furthermore, the ionization and heating of the atomizing gas was reported to positively affect finish qualities. Although ionization techniques have …

A Framework For Sustainable Material Selection For Multi-Generational Components, Ryan T. Bradley

Theses and Dissertations--Mechanical and Aerospace Engineering

The early stages of a product’s design are a critical time for decisions that impact the entire life-cycle cost. Product designers have mastered the first generation; however, they currently do not have the ability to know the impact of their decisions on the multi-generational view. This thesis aims at closing the gap between total life-cycle information and the traditional design process in order to harbor sustainable value creation among all stakeholders involved. A framework is presented that uses a combination of a life-cycle costing methodology and an evolutionary algorithm in order to achieve a sustainability assessment for a true multi-generational …

Joint Formation Under Severely Altered Background Atmosphere In Controlled Atmosphere Brazing Of Aluminum, Cheng-Nien Yu

Theses and Dissertations--Mechanical and Aerospace Engineering

Adverse changes of background atmosphere in a brazing chamber cause qualitative and quantitative deterioration of joint formation in an aluminum brazing process. This study offers an insight into the adverse effects with gradually adjusted atmospheric conditions in terms of oxygen and humidity levels. Corresponding responses of the molten clad flow and the joint formation upon resolidification vs. atmospheric conditions are documented by comparative tests involving self-fluxing and surface-fluxing brazing sheets: 1) in situ and in real time study of the onset of melting, clad flow, and joint formation, and 2) inclined wedge-tee mating tests for brazeability assessment. The surface-fluxing brazing …

An Analysis Of Energy Resources Utilization For Two Metal Joining Manufacturing Processes, Jonathan Gasser

Theses and Dissertations--Mechanical and Aerospace Engineering

Sustainable manufacturing involves utilizing energy resources efficiently. Currently, the state of sustainability for a given manufacturing process is described by most in a qualitative sense as opposed to using quantitative metrics. This thesis offers a segment of analysis needed to understand the state of sustainability in the context of energy resource utilization. This was accomplished by measuring the order of magnitude difference between the energy consumption of a manufacturing process vs. the theoretical minimum amount of energy required to complete the same task (aluminum T-joint bond). This analysis was completed for a TIG welding process and a controlled atmosphere brazing …

Shape Memory Behavior Of Single And Polycrystalline Nickel Rich Nickel Titanium Alloys, Irfan Kaya

Theses and Dissertations--Mechanical and Aerospace Engineering

NiTi is the most commonly used shape memory alloy (SMA) and has been widely used for bio-medical, electrical and mechanical applications. Nickel rich NiTi shape memory alloys are coming into prominence due to their distinct superelasticity and shape memory properties as compared to near equi-atomic NiTi shape memory alloys. Besides, their lower density and higher work output than steels makes these alloys an excellent candidate for aerospace and automotive industry. Shape memory properties and phase transformation behavior of high Ni-rich Ni₅₄Ti₄₆ (at.%) polycrystals and Ni-rich Ni₅₁Ti₄₉ (at.%) single-crystals are determined. Their properties are sensitive …

Precipitation, Orientation And Composition Effects On The Shape Memory Properties Of High Strength Nitihfpd Alloys, Emre Acar

Theses and Dissertations--Mechanical and Aerospace Engineering

NiTiHf high temperature shape memory alloys are attractive due to their high operating temperatures (>100 ^oC) and acceptable transformation strain compared to NiTi. However, NiTiHf has limitations due to their lack of ductility and low strength, resulting in poor shape memory properties. In this study, Pd has been added to NiTiHf alloys in an attempt to improve their shape memory behavior. A combined approach of quaternary alloying and precipitation strengthening was used.

The characterization of a Ni_45.3Ti_29.7Hf₂₀Pd₅ (at. %) polycrystalline alloy was performed in compression after selected aging treatments. Transmission electron …

Combining Sustainable Value Stream Mapping And Simulation To Assess Manufacturing Supply Chain Network Performance, Daniel T. Sparks

Theses and Dissertations--Mechanical and Aerospace Engineering

Sustainable Value Stream Mapping (Sus-VSM) builds upon traditional VSM to capture additional sustainability aspects of the product flow, such as environmental and societal aspects. This work presents research to expand the utility of Sus-VSM to supply chain networks, develop a general approach towards improving supply chain sustainability, and examine the benefits of implementing simulation and a design of experiments (DOE) style analysis. Metrics are identified to assess economic, environmental, and societal sustainability for supply chain networks and visual symbols are developed for the Supply Chain Sus-VSM (SC Sus-VSM) to allow users to easily identify locations where sustainability can be improved. …

A Metrics-Based Sustainability Assessment Of Cryogenic Machining Using Modeling And Optimization Of Process Performance, Tao Lu

Theses and Dissertations--Mechanical and Aerospace Engineering

The development of a sustainable manufacturing process requires a comprehensive evaluation method and fundamental understanding of the processes. Coolant application is a critical sustainability concern in the widely used machining process. Cryogenic machining is considered a candidate for sustainable coolant application. However, the lack of comprehensive evaluation methods leaves significant uncertainties about the overall sustainability performance of cryogenic machining. Also, the lack of practical application guidelines based on scientific understanding of the heat transfer mechanism in cryogenic machining limits the process optimization from achieving the most sustainable performance.

In this dissertation, based on a proposed Process Sustainability Index (ProcSI …

Lean Fire Management: A Focused Analysis Of The Incident Command System Based On Toyota Production System Principles, Jeremiah S. Fugate

Theses and Dissertations--Mechanical and Aerospace Engineering

A primary role of the Incident Command System is to learn from past incidents, as illustrated by its origins in the wildland firefighting community. Successful emergency response operations under the Incident Command System has prompted its nationwide spread, this promulgation critically relies on the system’s capability to stabilize and continuously improve various aspects of emergency response through effective organizational learning. The objective of this study is to evaluate the potential to apply fundamental principles of the Toyota Production System (Lean manufacturing) to improve learning effectiveness within the Incident Command System. An in-depth review of literature and training documents regarding both …

Kinetics Of Wedge-Tee Joint Formation During Brazing Of An Aluminum Alloy Under Controlled Atmosphere, Fangxiao Dong

Theses and Dissertations--Mechanical and Aerospace Engineering

This work involves investigation of the kinetics data of a joint formation during aluminum alloy brazing. Data was generated by several groups of experiments conducted under conditions of a controlled oxygen level of the background brazing atmosphere. Generated data are examined to identify the phases of the joint formation and the time frame of its evolution. Specifically, the triple line kinetics data are analyzed to verify whether a power law between (1) the triple line of the molten metal preceding joint formation and (2) the formation time can be established for each formation phase. In addition, both initial and residual …

Experimental Investigation To Inform Optimal Configurations For Dynamic Near-Field Passive Uhf Rfid Systems, Donnie E. Proffitt Ii

Theses and Dissertations--Mechanical and Aerospace Engineering

RFID has been characterized as a “disruptive technology” that has the potential to revolutionize numerous key sectors. A key advantage of passive RFID applications is the ability to wirelessly transmit automatic identification and related information using very little power. This paper presents an experimental investigation to inform the optimal configuration for programming passive ultra-high frequency (UHF) RFID media in dynamic applications. Dynamic programming solutions must be designed around the tag’s functionality, the physical programming configuration and environment. In this investigation, we present a methodology to determine an optimal configuration to maximize the systems programming efficiency for dynamic applications.

Process-Induced Surface Integrity In Machining Of Niti Shape Memory Alloys, Yusuf Kaynak

Theses and Dissertations--Mechanical and Aerospace Engineering

NiTi alloys have been the focus of Shape Memory Alloys (SMA) research and applications due their excellent ductility and shape memory properties, and these alloys have been extensively used in automotive, aerospace, and in biomedical applications.

The effects of machining on the surface integrity and the corresponding material and mechanical properties of alloys can be best studied by utilizing NiTi alloys as workpiece material since their physical and mechanical properties are highly microstructure dependent. However, due to very poor machining performance of NiTi shape memory alloys, no comprehensive or systematic investigation on this topic has been conducted by researchers as …

The Development Of A Predictive Probability Model For Effective Continuous Learning And Improvement, Michael Abbot Maginnis

Theses and Dissertations--Mechanical and Aerospace Engineering

It is important for organizations to understand the factors responsible for establishing sustainable continuous improvement (CI) capabilities. This study uses learning curves as the basis to examine learning obtained by team members doing work with and without the application of fundamental aspects of the Toyota Production System. The results are used to develop an effective model to guide organizational activities towards achieving the ability to continuous improve in a sustainable fashion.

This research examines the effect of standardization and waste elimination activities supported by systematic problem solving on team member learning at the work interface and system performance. The results …

Cryogenic Burnishing Of Co-Cr-Mo Biomedical Alloy For Enhanced Surface Integrity And Improved Wear Performance, Shu Yang

Theses and Dissertations--Mechanical and Aerospace Engineering

The functional performance of joint implants is largely determined by the surface layer properties in contact. Wear/debris-induced osteolysis and aseptic loosening has been identified as the major cause of failure of metal-on-metal joint implants. A crucial requirement for the long-term stability of the artificial joint is to minimize the release of debris particles.

Severe plastic deformation (SPD) processes have been used to modify the surface integrity properties by generating ultrafine, or even nano-sized grains and grain size gradients in the surface region of many materials. These fine grained materials often exhibit enhanced surface integrity properties and improved functional performance (wear …

Transport Phenomena Associated With Liquid Metal Flow Over Topographically Modified Surfaces, Wen Liu

Theses and Dissertations--Mechanical and Aerospace Engineering

Brazing and soldering, as advanced manufacturing processes, are of significant importance to industrial applications. It is widely accepted that joining by brazing or soldering is possible if a liquid metal wets the solids to be joined. Wetting, hence spreading and capillary action of liquid metal (often called filler) is of significant importance. Good wetting is required to distribute liquid metal over/between the substrate materials for a successful bonding.

Topographically altered surfaces have been used to exploit novel wetting phenomena and associated capillary actions, such as imbibitions (a penetration of a liquid front over/through a rough, patterned surface). Modification of surface …