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Articles 1 - 25 of 25
Full-Text Articles in Mechanical Engineering
Effects Of Iteration On Concept Development, Shivraj Ranganathan
Effects Of Iteration On Concept Development, Shivraj Ranganathan
All Theses
Iteration in the conceptual design stage is defined as repetition of design tasks to incorporate new information. A more concise definition of iteration relevant to this research would be the progression of design through different abstraction levels or design stages, defining and refining design solutions while progressing from initial concepts to a more detailed design. Although it is believed that iteration has a positive effect on the quality of ideas in the design process, this experimental study presents an opportunity to determine the effects of iteration on quality of concepts and the factors that lead to increased quality of concepts. …
Knowledge Base Representation With Axiomatic Design Rules For Concept Level Up Implement In Ontological Framework, Zhuochen Shi
Knowledge Base Representation With Axiomatic Design Rules For Concept Level Up Implement In Ontological Framework, Zhuochen Shi
All Theses
Axiomatic Design has been applied and developed as a tool, offering a scientific basis for design and improving design activities. Axiomatic Design has been used in various fields such as software system design, structure design, and product design. However, several challenges and limitations exist in Axiomatic Design including: the inconsistency in identifying design parameters, existence of coupled design, and multiple groups of functional requirements and design parameters. Aimed at using Axiomatic Design to generate conceptual solutions in engineering design while overcoming its limitations, a formal ontology is developed. The ontology defines functional requirements, design parameters, concepts, components and variables and …
Phonon Transport Analysis Of Semiconductor Nanocomposites Using Monte Carlo Simulations, Mayank Malladi
Phonon Transport Analysis Of Semiconductor Nanocomposites Using Monte Carlo Simulations, Mayank Malladi
All Theses
Nanocomposites are composite materials which incorporate nanosized particles, platelets or fibers. The addition of nanosized phases into the bulk matrix can lead to significantly different material properties compared to their macrocomposite counterparts. For nanocomposites, thermal conductivity is one of the most important physical properties. Manipulation and control of thermal conductivity in nanocomposites have impacted a variety of applications. In particular, it has been shown that the phonon thermal conductivity can be reduced significantly in nanocomposites due to the increase in phonon interface scattering while the electrical conductivity can be maintained. This extraordinary property of nanocomposites has been used to enhance …
A Study Of Gallery Method To Increase Idea Quality In Conceptual Design, Liz Mathew
A Study Of Gallery Method To Increase Idea Quality In Conceptual Design, Liz Mathew
All Theses
The objective of this research is to evaluate whether gallery method increases idea quality in conceptual design for engineering design problems. The gallery method is a group ideation process which allows individuals to first generate ideas individually, followed by pooling of ideas to conduct group ideation. Design engineers are often encouraged to work in groups to generate concepts and solutions for design problems. However, past research argues that individual ideation results in higher quality design concepts compared to the group ideation methods. The limitations of group ideation such as free riding, production blocking, evaluation apprehension, and goal incongruity are identified …
An Exploratory Study On The Effects Of Goal Alignment, Interventions, And Motivational Factors On Innovative Engineering Design Projects, Blake Linnerud
An Exploratory Study On The Effects Of Goal Alignment, Interventions, And Motivational Factors On Innovative Engineering Design Projects, Blake Linnerud
All Theses
Innovation has become an important facet of engineering design, both in industry and the academy. Many senior-level engineering design courses encourage students to develop innovative solutions to open design projects from industry sponsors. Like industry, these academic problems are tackled by teams of students. Student teams that function at the highest level are more likely to reach the innovative solutions for which they are searching. The research presented in this work focuses on two main areas: (1) understanding what motivates engineers when working on innovative design projects and (2) determining the effects of goal alignment interventions on design teams working …
Knowledge Extraction From Work Instructions Through Text Processing And Analysis, Abhiram Koneru
Knowledge Extraction From Work Instructions Through Text Processing And Analysis, Abhiram Koneru
All Theses
The objective of this thesis is to design, develop and implement an automated approach to support processing of historical assembly data to extract useful knowledge about assembly instructions and time studies to facilitate the development of decision support systems, for a large automotive original equipment manufacturer (OEM). At a conceptual level, this research establishes a framework for sustainable and scalable approach to extract knowledge from big data using techniques from Natural Language Processing (NLP) and Machine Learning (ML). Process sheets are text documents that contain detailed instructions to assemble a portion of the vehicle, specification of parts and tools to …
Analyzing Requirement Type Influence On Generated Solutions, Emily Worinkeng
Analyzing Requirement Type Influence On Generated Solutions, Emily Worinkeng
All Theses
Several ideation methods are available and used by engineering designers to enable the generation of alternative designs [1]. However, there has been little work done to understand the role that the design problem given to participants plays in the ideation process. The contribution of this research is found through the proposed guidelines with respect to the type of requirements to include as part of the design problem in order to achieve the desired quantity, quality, novelty, and variety of solutions during the early stages of the design process. This work is the first attempt at analyzing the effect of requirement …
Nonlinear Energy Harvesting Under White Noise, Qifan He
Nonlinear Energy Harvesting Under White Noise, Qifan He
All Theses
While purposeful introduction of stiffness nonlinearities into the dynamics of energy harvesters is aimed at enhancing performance under non-stationary and random excitations, most of the conclusions reported in the current literature are based on the steady-state response which assumes a harmonic fixed-frequency excitation. As a result, we still do not have a clear understanding of how the nature of the excitation influences the output power, or what role stiffness nonlinearities play in the transduction of energy harvesters under random excitations. To fill this gap in the current knowledge, this thesis investigates the response of nonlinear mono- and bi-stable energy harvesters …
Development Of Stationary And Mobile Tailgating Detection Solutions For Ground Vehicles, Tyler Zellmer
Development Of Stationary And Mobile Tailgating Detection Solutions For Ground Vehicles, Tyler Zellmer
All Theses
Improving the safety of North American roadways is a top priority for government agencies and transportation organizations alike. Regulations on appropriate driving behavior have been developed to minimize the likelihood of crashes occurring, but law enforcement tools remain to be fully developed and applied in the field. One prominent example of this is tailgating – the dangerous act of one ground vehicle following another too closely. This activity is responsible for thousands of crashes every year, but police officers currently have few tools to accurately detect and document tailgating events. Though tailgating often occurs in a wide variety of vehicle …
Design Optimization Of Geometrical Parameters And Material Properties Of Vibrating Bimorph Cantilever Beams With Solid And Honeycomb Substrates For Maximum Energy Harvested, Jasmin Adeshara
All Theses
The objective of this thesis is to maximize the energy harvested from a vibrating bimorph cantilever beam by optimizing the geometrical parameters and the material properties of the piezoelectric beam. A three-dimensional finite element (FEA) model is developed to design a vibrating bimorph cantilever beam for energy harvesting. The reference piezoelectric material used in the design is Lead Zirconate Titanate (PZT-5H) and the substrate sandwiched between the two piezoelectric plates is brass. Three types of models are analyzed and compared in this work by modifying the brass substrate geometry- a solid homogenous substrate, a regular honeycomb substrate and an auxetic …
Particle Electrophoresis And Magnetophoresis In Microchannels, Litao Liang
Particle Electrophoresis And Magnetophoresis In Microchannels, Litao Liang
All Theses
In current pharmaceutical and biotechnology industries with clinical applications, an increased demand for flow control and cell manipulation on the micrometer scale has emerged. Electrokinetic, magnetic and many other physics fields have been exploited to meet this demand. However, due to the requirement for sophisticated micro-structures and the interference of the increasing significance of many `trivial' physics properties (surface potential, permittivity, etc.) at the smaller scale, most applications encounter poor maneuverability and high operation/fabrication complexity issues. Very few attempts have been made to bypass these requirements while maintaining the same control and efficiency. This thesis research investigates the fundamental behaviors …
Novel Side-Vent-Channel Based Blast Mitigation Concept For Light Tactical Vehicles, Ramin Yavari
Novel Side-Vent-Channel Based Blast Mitigation Concept For Light Tactical Vehicles, Ramin Yavari
All Theses
A new concept solution for improving survivability of the light tactical military vehicles to blast-loads resulting from a shallow-buried mine detonated underneath such vehicles is proposed and critically assessed using computational engineering methods and tools. The solution is inspired by the principle of operation of the rocket-engine nozzles, in general and the so called 'pulse detonation' rocket engines, in particular, and is an extension of the recently introduced so-called 'blast chimney' concept (essentially a vertical channel connecting the bottom and the roof and passing through the cabin of a light tactical vehicle).
Relative to the blast-chimney concept, the new solution …
Topology Optimization Using A Level Set Penalization With Constrained Topology Features, Luis Fernandez
Topology Optimization Using A Level Set Penalization With Constrained Topology Features, Luis Fernandez
All Theses
Topology optimization techniques have been applied to structural design problems in order to determine the best material distribution in a given domain. The topology optimization problem is ill-posed because optimal designs tend to have infinite number of holes. In order to regularize this problem, a geometrical constraint, for instance the perimeter of the design (i.e., the measure of the boundary of the solid region, length in 2D problems or the surface area in 3D problems) is usually imposed. In this thesis, a novel methodology to solve the topology optimization problem with a constraint on the number of holes is proposed. …
Finite Element Analysis Of Effective Mechanical Properties, Vibration And Acoustic Performance Of Auxetic Chiral Core Sandwich Structures, Hrishikesh Joshi
Finite Element Analysis Of Effective Mechanical Properties, Vibration And Acoustic Performance Of Auxetic Chiral Core Sandwich Structures, Hrishikesh Joshi
All Theses
Honeycomb cellular materials are widely used in engineering applications due to their high strength to weight ratio and controllable effective mechanical properties. The effective properties are controlled by varying the geometry of the repetitive unit cells of honeycomb structure. Sandwich panels made of honeycomb cores are beneficial in many applications including vibration isolation and sound transmission reduction. Sandwich panels with standard honeycomb core configurations have previously been studied with regards to sound transmission behavior. It has been established that the auxetic honeycomb cores, having negative in-plane Poisson's ratio, exhibit higher sound transmission loss as compared to regular honeycomb cores. In …
Computational Representation Of Linguistic Semantics For Requirement Analysis In Engineering Design, Alex Lash
Computational Representation Of Linguistic Semantics For Requirement Analysis In Engineering Design, Alex Lash
All Theses
The objective of this research is to use computational linguistics to identify semantic implicit relationships between text-based relationships. Specifically, natural language processing is used to implement linguistic semantics in requirement analyzers. Linguistic semantics is defined as the meaning of words beyond their string form, part of speech, and syntactic function. Many existing design tools use part of speech tagging and sentence parsing as the foundation of their requirement analysis but ultimately use string algorithms to evaluate requirements. These string algorithms cannot capture the implicit knowledge in requirements. This research compares five methods of requirement analysis. A manual analysis provides the …
Identification Of And Effects On The Depth Of The Machining Affected Zone In Nickel-Based Superalloys, Boyce Richardson
Identification Of And Effects On The Depth Of The Machining Affected Zone In Nickel-Based Superalloys, Boyce Richardson
All Theses
The formation of subsurface damage during machining of nickel-based superalloys is a critical quality concern for the manufacture of gas turbine components. The identification and understanding of this zone are critical to the reduction of destructive testing and scrap costs in an ever changing manufacturing environment. This thesis seeks to provide a novel objective method for identification of the depth of this zone and an empirical model for the effects of machining parameters on this zone. This allows for optimal machining parameters to be used in manufacturing reducing the need for destructive testing, while also reducing manufacturing costs by reducing …
Computational Modeling Of The Friction Stir Welding (Fsw) Process And Of The Performance Of Fsw Joints, Ajay Prasad Arakere
Computational Modeling Of The Friction Stir Welding (Fsw) Process And Of The Performance Of Fsw Joints, Ajay Prasad Arakere
All Theses
Friction Stir Welding (FSW) is a solid-state metal-joining process. Within FSW, a (typically) cylindrical tool-pin (threaded at the bottom and terminated with a circular-plate shape shoulder, at the top) is driven between two firmly-clamped plates (placed on a rigid backing support). Due to a high normal downward pressure applied to the shoulder and due to frictional sliding and plastic-deformation, substantial amount of heat is generated at the tool/work-piece interface and in the region underneath the tool shoulder. Thermally plasticized work-piece material is then extruded around the traveling tool and forged into a welding-joint behind the tool. Due to its solid-state …
Modal Analysis To Minimize Gearbox Induced Noise Of General Electric Wind Turbines, Matthew Evans
Modal Analysis To Minimize Gearbox Induced Noise Of General Electric Wind Turbines, Matthew Evans
All Theses
With the current global emphasis on alternative green energy sources, wind turbine technologies have seen significant growth in recent years. Today, wind turbines are being produced and constructed at unprecedented levels with their sites inching closer and closer to residential communities. With that, wind turbine companies have been receiving growing complains about the noise emitted from these turbines during operation. To resolve this issue, many of these companies are spending more resources to design and manufacture quieter wind turbines. In particular, General Electric (GE) intends to reduce the noise created by their 2.5 MW CGDT wind turbines. Previous studies showed …
Magnetic Manipulation Of Particles And Cells In Ferrofluid Flow Through Straight Microchannels Using Two Magnets, Jian Zeng
All Theses
Microfluidic devices have been increasingly used in the past two decades for particle and cell manipulations in many chemical and biomedical applications. A variety of force fields have been demonstrated to control particle and cell transport in these devices including electric, magnetic, acoustic, and optical forces etc. Among these particle handling techniques, the magnetic approach provides clear advantages over others such as low cost, noninvasive, and free of fluid heating issues. However, the current knowledge of magnetic control of particle transport is still very limited, especially lacking is the handling of diamagnetic particle. This thesis is focused on the magnetic …
An Experimental Study On The Influence That Failure Number, Specialization, And Domain Have On Confidence In Predicting System Failures, Somaiah Thimmaiah
An Experimental Study On The Influence That Failure Number, Specialization, And Domain Have On Confidence In Predicting System Failures, Somaiah Thimmaiah
All Theses
Design reviews are typically used for three types of design activities: 1) identifying errors, 2) assessing the impact of the errors, and 3) suggesting solutions for the errors. This experimental study focuses on understanding the second issue as it relates to the number of errors considered, the existence of controls, and the level of domain familiarity of the assessor. A set of design failures and associated controls developed for a completed industry sponsored project is used as the experimental design problem. Non-domain individuals (psychology class students), domain generalists (first year engineering students), and domain specialists (graduate mechanical students) are provided …
Vibration And Acoustic Properties Of Honeycomb Sandwich Structures Subject To Variable Incident Plane-Wave Angle Pressure Loads, Jiaxue Yan
All Theses
Honeycomb structures are widely used in many areas for their material characteristics such as high strength-to-weight ratio, stiffness-to-weight, sound transmission, and other properties. Honeycomb structures are generally constructed from periodically spaced tessellations of unit cells. It can be shown that the effective stiffness and mass properties of honeycomb are controlled by the local geometry and wall thickness of the particular unit cells used. Of particular interest are regular hexagonal (6-sided) honeycomb unit cell geometries which exhibit positive effective Poisson's ratio, and modified 6-sided auxetic honeycomb unit cells with Poisson's ratio which is effectively negative; a property not found in natural …
Decision Support Systems For Assembly Line Planning -Modular Subsytems For A Large Scale Production Management System, Rahul Renu
All Theses
In the domain of assembly lines, process sheets are entities that carry assembly process descriptions (work instructions), assembly time estimations, product workspaces and other configuration management and control information. These process sheets get assigned to workstations during the process of assembly line balancing. In this research two tools have been developed to aid in the assembly line planning process. In order to ensure that assembly line workers do not intrude upon each other's workspace, two assembly processes operating on the same product workspace must not be assigned to the same station. Generating and maintaining product workspace information for every process …
Laser-Assisted Printing Of Alginate And Cellular Tubes, Jingyuan Yan
Laser-Assisted Printing Of Alginate And Cellular Tubes, Jingyuan Yan
All Theses
Laser-assisted printing such as laser-induced forward transfer (LIFT) has found increasing biofabrication applications as an orifice-free cell/organ printing approach. Unfortunately, there have been very few studies on its efficacy of three-dimensional (3D) printing performance. In addition, the effects of printing parameters on jet/droplet formation during the printing of Newtonian and non-Newtonian fluids are lacking. Therefore, it is important to investigate its printing process and quality. The resulting knowledge will help to better control the resulting printing quality and feature resolution.
The objective of this study is to investigate the feasibility of laser-assisted 3D printing process and its applicability in making …
Three-Dimensional Finite Element Analysis Of Sound Transmission Performance Of Honeycomb Sandwich Structures, Xin Wang
All Theses
Due to the lighter weight of honeycomb structures compared with a cuboid of similar material, honeycomb is widely used in applications requiring a high stiffness to weight ratio. One important honeycomb meta-structure is sandwich composites designed with a honeycomb core between two thin panel layers. The geometry of the honeycomb is formed from periodically spaced, non-overlapping unit cells. An important advantage of cellular materials such as honeycomb is that vibration and acoustic properties can be changed simply by changing the unit cell geometry variables such as included angle, cell wall thickness and length, while keeping the overall dimensions of the …
A Model-Free Approach To Vehicle Stability Control, Chinmay Pandit
A Model-Free Approach To Vehicle Stability Control, Chinmay Pandit
All Theses
This project explored the feasibility of using measured responses of a passenger car together with a fuzzy logic based control algorithm to sense the onset of under-steer (or loss of steering control) and mitigate or eliminate it. The controller is simple and robust and, unlike existing controllers, instead of comparing the vehicle response to that of an idealized model it makes decisions based solely upon the measured response of the car.
Simulations were conducted (using CarSim) of various vehicles executing the skid pad and the double lane change tests to characterize the vehicle behavior. Consistent and qualitatively similar patterns in …