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1.
Nguyen, Jason Nam.
A heuristic optimization method for the design of meso-scale truss structure for complex-shaped parts.
Degree: MS, Mechanical Engineering, 2012, Georgia Tech
URL: http://hdl.handle.net/1853/44810 
► Advances in additive manufacturing technologies have brought a new paradigm shift to both design and manufacturing. There is a much bigger design space in which…
(more)
▼ Advances in additive manufacturing technologies have brought a new paradigm shift to both design and manufacturing. There is a much bigger design space in which designers can achieve a level of complexity and customizability, which are infeasible using traditional manufacturing processes. One application of this technology is for fabrication of meso-scale lattice structures (MSLS). These types of structures are designed to have material where it is needed for specific applications. They are suitable for any weight-critical applications, particularly in industries where both low weight and high strength are desired. MSLS can easily have hundreds to thousands of individual strut, where the diameter of each strut can be treated as a design variable. As a result, the design process poses a computational challenge. Since the computational complexity of the design problem often scales exponentially with the number of design variables, topological optimization that requires multi-variable optimization algorithm is infeasible for large-scale problems.
In previous research, a new method was presented for efficiently optimizing MSLS by utilizing a heuristic that reduces the multivariable optimization problem to a problem of only two variables. The method is called the Size Matching and Scaling (SMS) method, which combines solid-body analysis and predefined unit-cell library to generate the topology of the structure. However, the method lacks a systematic methodology to generate the initial ground geometry for the design process, which limits the previous implementations of the SMS method to only simple, axis-aligned structures.
In this research, an augmented SMS method is presented. The augmented method includes the integration of free-mesh approach in generating the initial ground geometry. The software that embodies that ground geometry generation process is integrated to commercial CAD system that allows designer to set lattice size parameters through graphical user interface. In this thesis, the augmented method and the unit-cell library are applied to various design examples.
The augmented SMS method can be applied effectively in the design of conformal lattice structure with highly optimized stiffness and volume for complex surface. Conformal lattice structures are those conformed to the shape of a part's surface and that can used to stiffen or strengthen a complex and curved surface. This design approach removes the need for a rigorous topology optimization, which is a main bottleneck in designing MSLS.
Advisors/Committee Members: Rosen, David (Committee Chair), Kyum%22%29&pagesize-30">
Choi,
Seung-
Kyum (Committee Member),
Paredis, Chris (Committee Member).
Subjects/Keywords: Truss structures; Conformal lattice structures; Manufacturing processes; Rapid prototyping; Mathematical optimization; Trusses; Lattice theory
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APA (6th Edition):
Nguyen, J. N. (2012). A heuristic optimization method for the design of meso-scale truss structure for complex-shaped parts. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/44810
Chicago Manual of Style (16th Edition):
Nguyen, Jason Nam. “A heuristic optimization method for the design of meso-scale truss structure for complex-shaped parts.” 2012. Masters Thesis, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/44810.
MLA Handbook (7th Edition):
Nguyen, Jason Nam. “A heuristic optimization method for the design of meso-scale truss structure for complex-shaped parts.” 2012. Web. 15 Jan 2021.
Vancouver:
Nguyen JN. A heuristic optimization method for the design of meso-scale truss structure for complex-shaped parts. [Internet] [Masters thesis]. Georgia Tech; 2012. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/44810.
Council of Science Editors:
Nguyen JN. A heuristic optimization method for the design of meso-scale truss structure for complex-shaped parts. [Masters Thesis]. Georgia Tech; 2012. Available from: http://hdl.handle.net/1853/44810
2.
Stone, Thomas M.
Model development decisions under uncertainty in conceptual design.
Degree: MS, Mechanical Engineering, 2012, Georgia Tech
URL: http://hdl.handle.net/1853/44835
► Model development decisions are an important feature of engineering design. The quality of simulation models often dictates the quality of design decisions, seeing as models…
(more)
▼ Model development decisions are an important feature of engineering design. The quality of simulation models often dictates the quality of design decisions, seeing as models guide decision makers (DM) in choosing design decisions. A quality model accurately represents the modeled system and is helpful for exploring what-if scenarios, optimizing design parameters, estimating design performance, and predicting the effect of design changes. However, obtaining a quality model comes at a cost in terms of model development – in experimentation, labor, model development time, and simulation time. Thus, DMs must make appropriate trade-offs when considering model development decisions.
The primary challenge in model development is making decisions under significant uncertainty. This thesis addresses model development in the conceptual design phase where uncertainty levels are high. In the conceptual design phase, there are many information constraints which may include an incomplete requirements list, unclear design goals, and/or undefined resource constrains. During the embodiment design phase, the overall objective of the design is more clearly defined, and model development decisions can be made with respect to an overall objective function. For example, the objective may be to maximize profit, where the profit is a known function of the model output. In the conceptual design phase, this level of clarity is not always present, so the DM must make decisions under significant model uncertainty and objective uncertainty. In this thesis, conjoint analysis is employed to solicit the preferences of the decision maker for various model attributes, and the preferences are used to formulate a quasi-objective function during the conceptual design phase – where the overall design goals are vague. Epistemic uncertainty (i.e., imprecision) in model attributes is represented as intervals and propagated through the proposed model development framework.
The model development framework is used to evaluate the best course of action (i.e., model development decision) for a real-world packaging design problem. The optimization of medical product packaging is assessed via mass spring damper models which predict contact forces experienced during shipping and handling. Novel testing techniques are employed to gather information from drop tests, and preliminary models are developed based on limited information. Imprecision in preliminary test results are quantified, and multiple model options are considered. Ultimately, this thesis presents a model development framework in which decision makers have systematic guidance for choosing optimal model development decisions.
Advisors/Committee Members: Kyum%22%29&pagesize-30">
Choi,
Seung-
Kyum (Committee Co-Chair),
Schaefer, Dirk (Committee Co-Chair),
Jiao, Jianxin (Committee Member).
Subjects/Keywords: Model development; Conjoint analysis; Uncertainty; Decision-based-design; Engineering design; Decision support systems; Uncertainty (Information theory); Model-integrated computing
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APA (6th Edition):
Stone, T. M. (2012). Model development decisions under uncertainty in conceptual design. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/44835
Chicago Manual of Style (16th Edition):
Stone, Thomas M. “Model development decisions under uncertainty in conceptual design.” 2012. Masters Thesis, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/44835.
MLA Handbook (7th Edition):
Stone, Thomas M. “Model development decisions under uncertainty in conceptual design.” 2012. Web. 15 Jan 2021.
Vancouver:
Stone TM. Model development decisions under uncertainty in conceptual design. [Internet] [Masters thesis]. Georgia Tech; 2012. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/44835.
Council of Science Editors:
Stone TM. Model development decisions under uncertainty in conceptual design. [Masters Thesis]. Georgia Tech; 2012. Available from: http://hdl.handle.net/1853/44835
3.
Patel, Jiten.
Optimal design of mesostructured materials under uncertainty.
Degree: MS, Mechanical Engineering, 2009, Georgia Tech
URL: http://hdl.handle.net/1853/31829
► The main objective of the topology optimization is to fulfill the objective function with the minimum amount of material. This reduces the overall cost of…
(more)
▼ The main objective of the topology optimization is to fulfill the objective function with the minimum amount of material. This reduces the overall cost of the structure and at the same time reduces the assembly, manufacturing and maintenance costs because of the reduced number of parts in the final structure. The concept of reliability analysis can be incorporated into the deterministic topology optimization method; this incorporated scheme is referred to as Reliability-based Topology Optimization (RBTO). In RBTO, the statistical nature of constraints and design problems are defined in the objective function and probabilistic constraint. The probabilistic constraint can specify the required
reliability level of the system. In practical applications, however, finding global optimum in the presence of uncertainty is a difficult and computationally intensive task, since for every possible design a full stochastic analysis has to be performed for estimating various statistical
parameters. Efficient methodologies are therefore required for the solution of the stochastic part and the optimization part of the design process.
This research will explore a reliability-based synthesis method which estimates all the statistical parameters and finds the optimum while being less computationally intensive. The efficiency of the proposed method is achieved with the combination of topology optimization and stochastic approximation which utilizes a sampling technique such as Latin Hypercube Sampling (LHS) and surrogate modeling techniques such as Local Regression and Classification using Artificial Neural Networks (ANN). Local regression is comparatively less computationally intensive and produces good results in case of low probability of failures whereas Classification is particularly useful in cases where the reliability of failure has to be estimated with disjoint failure domains. Because
classification using ANN is comparatively more computationally demanding than Local regression, classification is only used when local regression fails to give the desired level of goodness of fit. Nevertheless, classification is an indispensible tool in estimating the
probability of failure when the failure domain is discontinuous.
Representative examples will be demonstrated where the method is used to design
customized meso-scale truss structures and a macro-scale hydrogen storage tank. The
final deliverable from this research will be a less computationally intensive and robust
RBTO procedure that can be used for design of truss structures with variable design
parameters and force and boundary conditions.
Advisors/Committee Members: Kyum%22%29&pagesize-30">
Choi,
Seung-
Kyum (Committee Chair),
Muhanna, Rafi (Committee Member),
Rosen, David (Committee Member).
Subjects/Keywords: Artificial neural networks; Local regression; Reliability analysis; Limit state approximation; Mesostructured materials; Topology optimization; Structural optimization; Topology; Trusses; Reliability (Engineering) Statistical methods
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APA (6th Edition):
Patel, J. (2009). Optimal design of mesostructured materials under uncertainty. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/31829
Chicago Manual of Style (16th Edition):
Patel, Jiten. “Optimal design of mesostructured materials under uncertainty.” 2009. Masters Thesis, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/31829.
MLA Handbook (7th Edition):
Patel, Jiten. “Optimal design of mesostructured materials under uncertainty.” 2009. Web. 15 Jan 2021.
Vancouver:
Patel J. Optimal design of mesostructured materials under uncertainty. [Internet] [Masters thesis]. Georgia Tech; 2009. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/31829.
Council of Science Editors:
Patel J. Optimal design of mesostructured materials under uncertainty. [Masters Thesis]. Georgia Tech; 2009. Available from: http://hdl.handle.net/1853/31829
4.
Rippel, Markus.
Improved robustness formulations and a simulation-based robust concept exploration method.
Degree: MS, Mechanical Engineering, 2009, Georgia Tech
URL: http://hdl.handle.net/1853/31850
► The goal when applying robust engineering design methods is to improve a system's quality by reducing its sensitivity to uncertainty that has influence on the…
(more)
▼ The goal when applying robust engineering design methods is to improve a system's quality by reducing its sensitivity to uncertainty that has influence on the performance of the product. In the Robust Concept Exploration Method (RCEM) this approach is facilitated with additionally giving the designer the possibility to search for a compromise between the desired performance and a satisfying robustness. The current version of the RCEM, however, has some limitations that render it inapplicable for nonlinear design problems. These limitations, which are demonstrated in this thesis, are mainly connected to the application of global response surfaces and the Taylor series for variance estimations.
In order to analyze the limitation of the robustness estimation, several alternative methods are developed, assessed and introduced to a modified RCEM. The developed Multiple Point Method is based on the Sensitivity Index (SI) and improves the variance estimation in RCEM significantly, especially for nonlinear problems. This approach is applicable to design problems, for which the performance functions are known explicitly.
For problems that require simulations for the performance estimation, the simulation-based RCEM is developed by introducing the Probabilistic Collocation Method (PCM) to robust concept exploration. The PCM is a surrogate model approach, which generates local response models around the points of interests with a minimum number of simulation runs. Those models are utilized in the modified-RCEM for the uncertainty analysis of the system's performance.
The proposed methods are tested with two examples each. The modified RCEM is validated with an artificial design problem as well as the design of a robust pressure vessel. The simulation-based RCEM is validated using the same artificial design problem and the design of a robust multifunctional Linear Cellular Alloy (LCA) heat exchanger for lightweight applications such as mobile computing. The structure of the theoretical and empirical validation of the methods follows the validation square.
Advisors/Committee Members: Allen, Janet K. (Committee Chair), Kyum%22%29&pagesize-30">
Choi,
Seung-
Kyum (Committee Member),
Mistree, Farrokh (Committee Member).
Subjects/Keywords: Robust design; Robust design method; Robust optimization; Engineering design method; Engineering design; Robust optimization; Computer simulation; Engineering design
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APA (6th Edition):
Rippel, M. (2009). Improved robustness formulations and a simulation-based robust concept exploration method. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/31850
Chicago Manual of Style (16th Edition):
Rippel, Markus. “Improved robustness formulations and a simulation-based robust concept exploration method.” 2009. Masters Thesis, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/31850.
MLA Handbook (7th Edition):
Rippel, Markus. “Improved robustness formulations and a simulation-based robust concept exploration method.” 2009. Web. 15 Jan 2021.
Vancouver:
Rippel M. Improved robustness formulations and a simulation-based robust concept exploration method. [Internet] [Masters thesis]. Georgia Tech; 2009. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/31850.
Council of Science Editors:
Rippel M. Improved robustness formulations and a simulation-based robust concept exploration method. [Masters Thesis]. Georgia Tech; 2009. Available from: http://hdl.handle.net/1853/31850
5.
Goksel, Lorens Sarim.
Fatigue and damage tolerance assessment of aircraft structure under uncertainty.
Degree: MS, Mechanical Engineering, 2013, Georgia Tech
URL: http://hdl.handle.net/1853/49124
► This thesis presents a new modeling framework and application methodology for the study of aircraft structures. The framework provides a ‘cradle-to-grave’ approach to structural analysis…
(more)
▼ This thesis presents a new modeling framework and application methodology for
the study of aircraft structures. The framework provides a ‘cradle-to-grave’ approach to
structural analysis of a component, where structural integrity encompasses all phases of
its lifespan.
The methodology examines the holistic structural design of aircraft components
by integrating fatigue and damage tolerance methodologies. It accomplishes this by
marrying the load inputs from a fatigue analysis for new design, into a risk analysis for an
existing design. The risk analysis incorporates the variability found from literature,
including recorded defects, loadings, and material strength properties.
The methodology is verified via formal conceptualization of the structures, which
are demonstrated on an actual hydraulic accumulator and an engine nacelle inlet. The
hydraulic accumulator is examined for structural integrity utilizing different base
materials undergoing variable amplitude loading. Integrity is accomplished through a
risk analysis by means of fault tree analysis. The engine nacelle inlet uses the damage
tolerance philosophy for a sonic fatigue condition undergoing both constant amplitude
loading and a theoretical flight design case. Residual strength changes are examined
throughout crack growth, where structural integrity is accomplished through a risk
analysis of component strength versus probability of failure.
Both methodologies can be applied to nearly any structural application, not
necessarily limited to aerospace.
Advisors/Committee Members: Jiao, Roger (advisor), Scott, David (advisor), Kyum%22%29&pagesize-30">
Choi,
Seung-
Kyum (committee member).
Subjects/Keywords: Fatigue; Damage tolerance; Aircraft structures; FEM; Risk analysis; Probability of failure probability of detection; Aluminum; Crack growth; Airframes; Airframes Fatigue; Airplanes Fuselage; Risk assessment
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APA (6th Edition):
Goksel, L. S. (2013). Fatigue and damage tolerance assessment of aircraft structure under uncertainty. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/49124
Chicago Manual of Style (16th Edition):
Goksel, Lorens Sarim. “Fatigue and damage tolerance assessment of aircraft structure under uncertainty.” 2013. Masters Thesis, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/49124.
MLA Handbook (7th Edition):
Goksel, Lorens Sarim. “Fatigue and damage tolerance assessment of aircraft structure under uncertainty.” 2013. Web. 15 Jan 2021.
Vancouver:
Goksel LS. Fatigue and damage tolerance assessment of aircraft structure under uncertainty. [Internet] [Masters thesis]. Georgia Tech; 2013. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/49124.
Council of Science Editors:
Goksel LS. Fatigue and damage tolerance assessment of aircraft structure under uncertainty. [Masters Thesis]. Georgia Tech; 2013. Available from: http://hdl.handle.net/1853/49124
Georgia Tech
6.
McKeand, Austin Monroe.
Multilevel upscaling and validation framework for simulation of turbine engine components.
Degree: MS, Mechanical Engineering, 2020, Georgia Tech
URL: http://hdl.handle.net/1853/63566
► Efficient modeling of manufacturing uncertainty is critical in the design of turbine engine components. In this research, a multilevel validation framework is developed to efficiently…
(more)
▼ Efficient modeling of manufacturing uncertainty is critical in the design of turbine engine components. In this research, a multilevel validation framework is developed to efficiently account for the geometric and material uncertainty associated with the manufacturing process to accurately predict the performance of engine components. This framework is created to handle both epistemic and aleatory uncertainty. Specifically, the spatial variability of the uncertain geometric parameters obtained from coordinate measuring machine data of manufactured parts is represented as aleatory uncertainty. Porosity and defects in the manufactured parts based on 3D X-ray CT scanned images are represented as epistemic uncertainty. Multiple efficient statistic tools are integrated into the proposed framework. Karhunen-Loeve expansion is utilized to create a set of correlated random variables from the obtained uncertainty data and a fine scale finite element model of the component is created that accounts for the uncertainties quantified by these correlated random variables. A stochastic upscaling method is then developed to form a simplified model that can represent this detailed model with high accuracy under uncertainties. In addition, a validation method for multi-variate responses is developed and used to validate the simulation results with the experimental results. The modal frequency analysis of a turbine blade example is used to demonstrate the efficacy of the proposed framework. The application results show that the proposed method effectively captures the geometric uncertainties introduced by manufacturing while providing accurate predictions under uncertainties.
Advisors/Committee Members: Kyum%22%29&pagesize-30">
Choi,
Seung-
Kyum (advisor),
Wang, Yan (committee member),
Jiao, Roger (committee member).
Subjects/Keywords: Turbine; Engine; Blade; Uncertainty; Quantification; Stochastic; Upscaling; Validation; Simulation; Design; Frequency; Analysis
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APA (6th Edition):
McKeand, A. M. (2020). Multilevel upscaling and validation framework for simulation of turbine engine components. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/63566
Chicago Manual of Style (16th Edition):
McKeand, Austin Monroe. “Multilevel upscaling and validation framework for simulation of turbine engine components.” 2020. Masters Thesis, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/63566.
MLA Handbook (7th Edition):
McKeand, Austin Monroe. “Multilevel upscaling and validation framework for simulation of turbine engine components.” 2020. Web. 15 Jan 2021.
Vancouver:
McKeand AM. Multilevel upscaling and validation framework for simulation of turbine engine components. [Internet] [Masters thesis]. Georgia Tech; 2020. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/63566.
Council of Science Editors:
McKeand AM. Multilevel upscaling and validation framework for simulation of turbine engine components. [Masters Thesis]. Georgia Tech; 2020. Available from: http://hdl.handle.net/1853/63566
Georgia Tech
7.
Alzahrani, Mahmoud Ali.
Design of truss-like cellular structures using density information from topology optimization.
Degree: MS, Mechanical Engineering, 2014, Georgia Tech
URL: http://hdl.handle.net/1853/52275
► The advances in additive manufacturing removed most of the limitations that were once stopping designers when it comes to the manufacturability of the design. It…
(more)
▼ The advances in additive manufacturing removed most of the limitations that were once stopping designers when it comes to the manufacturability of the design. It allowed designers to produce parts with high geometric complexity such as cellular structures. These structures are known for their high strength relative to their low mass, good energy absorption, and high thermal and acoustic insulation compared to their relative solid counter-parts. Lattice structures, a type of cellular structures, have received considerable attention due to their properties when producing light-weight with high strength parts. The design of these structures can pose a challenge to designers due to the sheer number of variables that are present. Traditional optimization approaches become an infeasible approach for designing them, which motivated researchers to search for other alternative approaches.
In this research, a new method is proposed by utilizing the material density information obtained from the topology optimization of continuum structures. The efficacy of the developed method will be compared to existing methods, such as the Size Matching and Scaling (SMS) method that combines solid-body analysis and a predefined unit-cell library. The proposed method shows good potential in structures that are subjected to multiple loading conditions compared to SMS, which would be advantageous in creating reliable structures. In order to demonstrate the applicability of the proposed method to practical engineering applications, the design problem of a commercial elevator sling will be considered.
Advisors/Committee Members: Kyum%22%29&pagesize-30">
Choi,
Seung-
Kyum (advisor),
Rosen, David W. (committee member),
Wang, Yan (committee member).
Subjects/Keywords: RDM; Lattice structures; Topology optimization; Cellular structures
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APA ·
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APA (6th Edition):
Alzahrani, M. A. (2014). Design of truss-like cellular structures using density information from topology optimization. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/52275
Chicago Manual of Style (16th Edition):
Alzahrani, Mahmoud Ali. “Design of truss-like cellular structures using density information from topology optimization.” 2014. Masters Thesis, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/52275.
MLA Handbook (7th Edition):
Alzahrani, Mahmoud Ali. “Design of truss-like cellular structures using density information from topology optimization.” 2014. Web. 15 Jan 2021.
Vancouver:
Alzahrani MA. Design of truss-like cellular structures using density information from topology optimization. [Internet] [Masters thesis]. Georgia Tech; 2014. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/52275.
Council of Science Editors:
Alzahrani MA. Design of truss-like cellular structures using density information from topology optimization. [Masters Thesis]. Georgia Tech; 2014. Available from: http://hdl.handle.net/1853/52275
Georgia Tech
8.
Chang, Patrick.
An improved size, matching, and scaling synthesis method for the design of
meso-scale truss structures.
Degree: MS, Mechanical Engineering, 2011, Georgia Tech
URL: http://hdl.handle.net/1853/41138
► The recent improvement of additive manufacturing has allowed designers to achieve a level of complexity and customizability that is difficult or impossible to accomplish using…
(more)
▼ The recent improvement of additive manufacturing has allowed designers to achieve a level of complexity and customizability that is difficult or impossible to accomplish using traditional manufacturing processes. As a result, much research has been conducted on developing new methods to utilize the larger design space brought by additive manufacturing. One such research area is in the design of mesoscale lattice structures. Mesoscale lattice structures are a type of cellular structure with support element sizes on the order of magnitude of centimeters. These types of structures are engineered for high performance and have applications in industries where both low weight and high strength are desired. However, due to the small size of their struts, these structures can easily have hundreds to thousands of individual struts. As a result, design poses a unique challenge. Current methods approach design of mesoscale lattice structures as a topological optimization problem, treating each strut diameter in the structure as a design variable. For structures with a fewer number struts, these optimization methods can converge, but will generally be very time-consuming. For structures with a large number of struts, the optimization problem becomes too large for current algorithms to solve.
In previous research, a new, highly efficient design method for mesoscale lattice structures was presented that eliminates the need for global size or topological optimization. This method, termed the Size, Matching and Scaling method, used a unique combination of a solid-body finite element analysis and a library of pre-defined lattice configurations, termed the "unit-cell library," to generate lattice topologies. The results from this method were highly promising: design time was significantly reduced when compared to optimization methods. Furthermore, lattices designed using the SMS method had performance results that were either comparable or better than their optimized counterparts. However, the method developed was highly conceptual, lacking a true systematic methodology for generating topologies and suffering from some gaps in implementation.
In this research, we present a modified Size Matching and Scaling (SMS) design method. Firstly, we introduce and outline the modified methodology. This methodology particularly includes an optimization step for determining strut diameters that replaces the manual search used in the original method. Secondly, we expand and explore the unit-cell library in an attempt to improve the performance of lattices generated using the SMS method. In particular, we optimize several unit-cell configurations and compare their performance in the context of the SMS method. Finally, we test the updated SMS methodology and unit-cell library using various design examples.
Results from the various example problems indicate that optimization is not only a viable systematic method for determining diameter values, but is actually preferred to the manual, iterative process used in the original method.…
Advisors/Committee Members: Rosen, David (Committee Chair), Kyum%22%29&pagesize-30">
Choi,
Seung-
Kyum (Committee Member),
Paredis, Christiaan (Committee Member).
Subjects/Keywords: L-bracket; Simply-loaded beam; Cantilever; Truss; Trusses; Manufacturing processes; Mathematical optimization
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APA (6th Edition):
Chang, P. (2011). An improved size, matching, and scaling synthesis method for the design of
meso-scale truss structures. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/41138
Chicago Manual of Style (16th Edition):
Chang, Patrick. “An improved size, matching, and scaling synthesis method for the design of
meso-scale truss structures.” 2011. Masters Thesis, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/41138.
MLA Handbook (7th Edition):
Chang, Patrick. “An improved size, matching, and scaling synthesis method for the design of
meso-scale truss structures.” 2011. Web. 15 Jan 2021.
Vancouver:
Chang P. An improved size, matching, and scaling synthesis method for the design of
meso-scale truss structures. [Internet] [Masters thesis]. Georgia Tech; 2011. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/41138.
Council of Science Editors:
Chang P. An improved size, matching, and scaling synthesis method for the design of
meso-scale truss structures. [Masters Thesis]. Georgia Tech; 2011. Available from: http://hdl.handle.net/1853/41138
Georgia Tech
9.
Gong, Xuejian.
Collaborative-crowdsourcing product fulfillment for open design and manufacturing.
Degree: MS, Mechanical Engineering, 2018, Georgia Tech
URL: http://hdl.handle.net/1853/59956
► The open business model has attracted much attention from academia and industries alike. It implies many new opportunities for product innovatiopn to transend traditional boundaries…
(more)
▼ The open business model has attracted much attention from academia and industries alike. It implies many new opportunities for product innovatiopn to transend traditional boundaries and leaverage diverse capabilitied and resources by coherently integrating external partners into the design and manufacturing processes. Such trends lead to the decentralization of the product fulfillment process. Particularly, the open business model offers the opportunities for the small and medium enterprises to fulfill various customer needs in an innovative crowdsourcing manner. While open design and manufacturing sounds appealing, research on formal formulation of crowdsourcing product fulfillment has been very limited. The underlying challenge for adoption and reversion of the open business strategy is the difficulty in justify the population dynamics of crowdsourcing. This thesis puts forward collaborative-crowdsourcing product fulfillment (C2PF) for open design and manufacturing. This work proposes a new product fulfillment workflow to accommodate the decentralized yet collaborative product fulfillment process. The research focus is geared towards the instantiation of the open design and manufacturing with a highly individualized dental braces fulfillment process as a case study. The thesis investigates the fundamental issues underpinning open design and manufacturing. A game-theoretic decision framework is proposed to deal with such critical issues as (1) group decision-making in the product fulfillment processes, (2) dynamics analysis of the external partners’ population, and (3) collaboration-negotiation contracting scheme based on an information contents measure. Since the boundaries are opened to the external partners, the product fulfillment decision-making processes must be reengineered to adapt the collaborative-crowdsourcing process. The workflow of C2PF is established. The supply contracting mechanism is identified as the key pillars to support the product fulfillment flow. In addition, to model the population dynamics of the partners, an evolutionary competition-cooperation game theoretic model is established. The relationships among participation fraction of the partners, the balance of inter-domain capacity, and income and distribution have been established. It reveals a competition-cooperation relationship between the external partners and a co-evolutionary characteristic of the entire population. This model provides a guideline for the management of the open enterprise, with considering of the long-time prosperity. Moreover, to achieve the collaborative crowdsourcing, a generalized supply contracting evaluation mechanism has been proposed. This mechanism supports the collaborative-negotiation from the bidding perspective. The evaluation mechanism handles the uncertainty, aggregates multi-criteria evaluation results and ensures the satisfaction of the requirements. The proposed theory is applied to the open design and manufacturing, respectively. Furthermore, a case study of the dental brace product fulfillment…
Advisors/Committee Members: Jiao, Jianxin Roger (advisor), Nagi, Gebraeel (advisor), Kyum%22%29&pagesize-30">
Choi,
Seung-
Kyum (committee member),
Yao, Donggang (committee member).
Subjects/Keywords: Open enterprise; Open business model; Open innovation; Open design; Open manufacturing; Distributed product fulfillment; Crowdsourcing; Collaborative negotiation; Supply contracting; Game-theoretic decisions
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APA (6th Edition):
Gong, X. (2018). Collaborative-crowdsourcing product fulfillment for open design and manufacturing. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/59956
Chicago Manual of Style (16th Edition):
Gong, Xuejian. “Collaborative-crowdsourcing product fulfillment for open design and manufacturing.” 2018. Masters Thesis, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/59956.
MLA Handbook (7th Edition):
Gong, Xuejian. “Collaborative-crowdsourcing product fulfillment for open design and manufacturing.” 2018. Web. 15 Jan 2021.
Vancouver:
Gong X. Collaborative-crowdsourcing product fulfillment for open design and manufacturing. [Internet] [Masters thesis]. Georgia Tech; 2018. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/59956.
Council of Science Editors:
Gong X. Collaborative-crowdsourcing product fulfillment for open design and manufacturing. [Masters Thesis]. Georgia Tech; 2018. Available from: http://hdl.handle.net/1853/59956
Georgia Tech
10.
Wang, Shu.
Workforce scheduling with large-scale mixed integer programming using column generation and 2D genetic algorithms: An application to airport ground staff scheduling.
Degree: MS, Electrical and Computer Engineering, 2019, Georgia Tech
URL: http://hdl.handle.net/1853/62356
► Due to the large volume of transportation that takes place on the airport every day, airlines need to efficiently manage their employees and tasks to…
(more)
▼ Due to the large volume of transportation that takes place on the airport every day, airlines need to efficiently manage their employees and tasks to guarantee necessary operations are performed well and on time. The quality of the workforce scheduling has an important influence on both the task performance and costs of labor and operations that airlines will take. In this regard, this thesis proposes a mathematical modeling for airport ground staff scheduling with corresponding algorithms, including a 2D GA for shift planning with daily-wise shift formats, column generation for rostering and task dispatching, and integer programming for disruption management. The presented optimization-based workforce scheduling can replace the manual planning or serve as a reference for practitioners.
Advisors/Committee Members: Jiao, Roger (advisor), Meliopoulos, A. P. (advisor), Kyum%22%29&pagesize-30">
Choi,
Seung-
Kyum (advisor),
Zhang, Ying (advisor).
Subjects/Keywords: Workforce scheduling; Genetic algorithm; Column generation; Integer programming; Shift planning; Rostering
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APA (6th Edition):
Wang, S. (2019). Workforce scheduling with large-scale mixed integer programming using column generation and 2D genetic algorithms: An application to airport ground staff scheduling. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/62356
Chicago Manual of Style (16th Edition):
Wang, Shu. “Workforce scheduling with large-scale mixed integer programming using column generation and 2D genetic algorithms: An application to airport ground staff scheduling.” 2019. Masters Thesis, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/62356.
MLA Handbook (7th Edition):
Wang, Shu. “Workforce scheduling with large-scale mixed integer programming using column generation and 2D genetic algorithms: An application to airport ground staff scheduling.” 2019. Web. 15 Jan 2021.
Vancouver:
Wang S. Workforce scheduling with large-scale mixed integer programming using column generation and 2D genetic algorithms: An application to airport ground staff scheduling. [Internet] [Masters thesis]. Georgia Tech; 2019. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/62356.
Council of Science Editors:
Wang S. Workforce scheduling with large-scale mixed integer programming using column generation and 2D genetic algorithms: An application to airport ground staff scheduling. [Masters Thesis]. Georgia Tech; 2019. Available from: http://hdl.handle.net/1853/62356
Georgia Tech
11.
Hwang, Sungkun.
Predicting reliability in multidisciplinary engineering systems under uncertainty.
Degree: MS, Mechanical Engineering, 2016, Georgia Tech
URL: http://hdl.handle.net/1853/54955
► The proposed study develops a framework that can accurately capture and model input and output variables for multidisciplinary systems to mitigate the computational cost when…
(more)
▼ The proposed study develops a framework that can accurately capture and model input and output variables for multidisciplinary systems to mitigate the computational cost when uncertainties are involved. The dimension of the random input variables is reduced depending on the degree of correlation calculated by relative entropy. Feature extraction methods; namely Principal Component Analysis (PCA), the Auto-Encoder (AE) algorithm are developed when the input variables are highly correlated. The Independent Features Test (IndFeaT) is implemented as the feature selection method if the correlation is low to select a critical subset of model features. Moreover, Artificial Neural Network (ANN) including Probabilistic Neural Network (PNN) is integrated into the framework to correctly capture the complex response behavior of the multidisciplinary system with low computational cost. The efficacy of the proposed method is demonstrated with electro-mechanical engineering examples including a solder joint and stretchable patch antenna examples.
Advisors/Committee Members: Kyum%22%29&pagesize-30">
Choi,
Seung-
Kyum (advisor),
Wang, Yan (committee member),
Zhang, Ying (committee member).
Subjects/Keywords: Stretchable electronics; Dimension reduction; Feature extraction; Feature selection; Artificial neural network; Probabilistic neural network
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Manager
APA (6th Edition):
Hwang, S. (2016). Predicting reliability in multidisciplinary engineering systems under uncertainty. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/54955
Chicago Manual of Style (16th Edition):
Hwang, Sungkun. “Predicting reliability in multidisciplinary engineering systems under uncertainty.” 2016. Masters Thesis, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/54955.
MLA Handbook (7th Edition):
Hwang, Sungkun. “Predicting reliability in multidisciplinary engineering systems under uncertainty.” 2016. Web. 15 Jan 2021.
Vancouver:
Hwang S. Predicting reliability in multidisciplinary engineering systems under uncertainty. [Internet] [Masters thesis]. Georgia Tech; 2016. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/54955.
Council of Science Editors:
Hwang S. Predicting reliability in multidisciplinary engineering systems under uncertainty. [Masters Thesis]. Georgia Tech; 2016. Available from: http://hdl.handle.net/1853/54955
Georgia Tech
12.
Hammoud, Nader.
Enhancement of Parking Spot Detection Using an Affordable Laser Range Sensor.
Degree: MS, Mechanical Engineering, 2015, Georgia Tech
URL: http://hdl.handle.net/1853/56225
► To gain a better understanding of the impact of parking spaces on traffic congestion, road infrastructure, time spent searching for parking and ultimately CO2 emissions,…
(more)
▼ To gain a better understanding of the impact of parking spaces on traffic congestion, road infrastructure, time spent searching for parking and ultimately CO2 emissions, several parking surveys have been undertaken. Traditionally these surveys were performed by individuals manually logging parking lot information, thus limiting spatial and temporal coverage due to high labor costs. As a result, the need for automating the data collection process for open parking spaces is paramount when one starts looking into using parking lot information in real-time applications and across a large area such as a city, state, or even an entire country. Some studies have been conducted looking into this automation process, such as using ultrasonic sensors, 2D LIDARs, vision sensors, parking lot cameras and sensors for individual parking spots in a lot. Most of these methods generated promising results, but were either expensive or not suitable for real-time processing.
This thesis describes an affordable method to detect parking spots in real-time by installing a low cost, off-the-shelf laser range sensors onto a probe car. Several algorithms will investigate the effect of having a stationary sensor and enabling a vertical motion of the sensor, with hopes of obtaining 3D images of a parking lot. The experiments are conducted for different parking configurations, in normal and adverse weather conditions. The results were compared to onboard ground truth camera recordings of the experiments. Statistical analyses were also performed to determine how effective a laser range sensor is in mapping a parking lot in one run; and how many runs were necessary to map the parking lot with a certain confidence.
Results show that the stationary laser range sensor maps parking spots with high accuracy, successfully generating a 2D and 3D layout of the parking configuration. Moreover, it has been shown that the sensor’s accuracy does not diminish for adverse weather conditions. The vertical motion of the sensor on the other hand helps with detecting some black cars, which are not as efficiently identified by the stable sensor.
Advisors/Committee Members: Bras, Bert (advisor), Kyum%22%29&pagesize-30">
Choi,
Seung-
Kyum (committee member),
Jiao, Roger (committee member).
Subjects/Keywords: Parking; Laser Sensor; Detection
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APA (6th Edition):
Hammoud, N. (2015). Enhancement of Parking Spot Detection Using an Affordable Laser Range Sensor. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/56225
Chicago Manual of Style (16th Edition):
Hammoud, Nader. “Enhancement of Parking Spot Detection Using an Affordable Laser Range Sensor.” 2015. Masters Thesis, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/56225.
MLA Handbook (7th Edition):
Hammoud, Nader. “Enhancement of Parking Spot Detection Using an Affordable Laser Range Sensor.” 2015. Web. 15 Jan 2021.
Vancouver:
Hammoud N. Enhancement of Parking Spot Detection Using an Affordable Laser Range Sensor. [Internet] [Masters thesis]. Georgia Tech; 2015. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/56225.
Council of Science Editors:
Hammoud N. Enhancement of Parking Spot Detection Using an Affordable Laser Range Sensor. [Masters Thesis]. Georgia Tech; 2015. Available from: http://hdl.handle.net/1853/56225
13.
Dietz, Timothy Paul.
Conceptual design of multi-domain systems: products and materials.
Degree: MS, Mechanical Engineering, 2010, Georgia Tech
URL: http://hdl.handle.net/1853/33867
► A key challenge facing designers creating innovative products is concept generation. Conceptual design is more effective when the design space is broadened by using an…
(more)
▼ A key challenge facing designers creating innovative products is concept generation. Conceptual design is more effective when the design space is broadened by using an integrated design of product and material concepts approach. Conceptual design can also be accelerated by including problem solving and solution triggering tools in its structure. In this approach, structured analogy is used to transfer underlying principles from a solution suitable in one domain (i.e., product or mechanical domain) to an analogous solution in another domain (i.e., material domain). The nature of design analogy does not require as full of an exploration of the target domain as would otherwise be necessary; affording the possibility of a more rapid development. The addition of problem solving and solution triggering tools to a design method also decreases the design time and/or improves the quality of the final solution.
This approach is formulated through a combination of the Theory of Inventive Problem Solving (TRIZ) proposed by Altshuller, and the systematic approach of Pahl and Beitz, for products that are jointly considered at the product and material level. These types of problems are ones where customer performance requirements are fulfilled through both the designed product and the designed material. The systematic approach of Pahl and Beitz is used as the base method through which TRIZ is used as a means of transferring abstract information about the design problem between the domains with the aim of accelerating conceptual design. This also allows for multi-domain design tools such as Su-Field-Model integration with design repositories for the transfer of information at different levels of abstraction; expanding the design space and effectively directing the designer. The explanation of this approach is presented through a simple example of a spring design improvement and validated through concept generation of a reactive material containment system.
Advisors/Committee Members: Mistree, Farrokh (Committee Chair), Allen, Janet K. (Committee Member), kyum%22%29&pagesize-30">
Choi,
Seung-
kyum (Committee Member),
McDowell, David (Committee Member).
Subjects/Keywords: TIPS; TRIZ; Systematic design; Materials design; Product design; Design; Multi-domain systems; Engineering design; Problem solving; Decision support systems
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APA (6th Edition):
Dietz, T. P. (2010). Conceptual design of multi-domain systems: products and materials. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/33867
Chicago Manual of Style (16th Edition):
Dietz, Timothy Paul. “Conceptual design of multi-domain systems: products and materials.” 2010. Masters Thesis, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/33867.
MLA Handbook (7th Edition):
Dietz, Timothy Paul. “Conceptual design of multi-domain systems: products and materials.” 2010. Web. 15 Jan 2021.
Vancouver:
Dietz TP. Conceptual design of multi-domain systems: products and materials. [Internet] [Masters thesis]. Georgia Tech; 2010. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/33867.
Council of Science Editors:
Dietz TP. Conceptual design of multi-domain systems: products and materials. [Masters Thesis]. Georgia Tech; 2010. Available from: http://hdl.handle.net/1853/33867
Georgia Tech
14.
Park, Sang-In.
Estimating mechanical properties of cellular solid materials from additive manufacturing processes.
Degree: PhD, Mechanical Engineering, 2016, Georgia Tech
URL: http://hdl.handle.net/1853/59124
► the inherent limitations of the AM process. This research aims to develop a mechanical property-estimation procedure for additively manufactured cellular materials by considering the effects…
(more)
▼ the inherent limitations of the AM process. This research aims to develop a mechanical property-estimation procedure for additively manufactured cellular materials by considering the effects of AM processes. In order to clearly understand the AM process, related parameters are categorized into four groups: (a) Design and Manufacturing process parameters (DMP), (b) Layer deposition parameters (LDP), (c) Structural element parameters (SEP), and (d) Cellular material properties (CMP). Three transformations are defined among these groups. Firstly, the functional relationship between DMPs and LDPs is established based on process-modeling simulation. The variation in LDPs due to manufacturing instabilities is quantified in the form of a stochastic distribution. Next, an as-fabricated voxel modeling approach is developed for describing the propagation of geometrical degradation from LDPs to SEPs. The effective values of SEPs are determined based on semi-rigid joint frame element formulation. Finally, a discrete homogenization approach is implemented with the semi-rigid elements to integrate the effects of AM processes into the mechanical XVI property estimation procedure. The estimation framework developed in this research can be applied to analyze the performance of additively manufactured cellular materials and help to design of cellular materials.
Advisors/Committee Members: Rosen, David (advisor), Kyum%22%29&pagesize-30">
Choi,
Seung-
Kyum (committee member),
Wang, Yan (committee member),
Ruzzene, Massimo (committee member),
Duty, Chad (committee member).
Subjects/Keywords: As-fabricated voxel model; Homogenization; Semi-rigid joint frame
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APA (6th Edition):
Park, S. (2016). Estimating mechanical properties of cellular solid materials from additive manufacturing processes. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/59124
Chicago Manual of Style (16th Edition):
Park, Sang-In. “Estimating mechanical properties of cellular solid materials from additive manufacturing processes.” 2016. Doctoral Dissertation, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/59124.
MLA Handbook (7th Edition):
Park, Sang-In. “Estimating mechanical properties of cellular solid materials from additive manufacturing processes.” 2016. Web. 15 Jan 2021.
Vancouver:
Park S. Estimating mechanical properties of cellular solid materials from additive manufacturing processes. [Internet] [Doctoral dissertation]. Georgia Tech; 2016. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/59124.
Council of Science Editors:
Park S. Estimating mechanical properties of cellular solid materials from additive manufacturing processes. [Doctoral Dissertation]. Georgia Tech; 2016. Available from: http://hdl.handle.net/1853/59124
15.
Spurlock, Chad M.
Influence of hull configuration and vessel propulsion systems on sea turtle shell injuries.
Degree: PhD, Civil and Environmental Engineering, 2012, Georgia Tech
URL: http://hdl.handle.net/1853/44886
► Loggerhead sea turtles in coastal waters often sustain injuries from vessel impacts. The influences of vessel hull configuration and propulsion system type on the incidence…
(more)
▼ Loggerhead sea turtles in coastal waters often sustain injuries from vessel impacts. The influences of vessel hull configuration and propulsion system type on the incidence and severity of wounds in turtle/vessel interaction were investigated. Full-scale field tests using two vessels with deep-vee hulls were performed. An artificial carapace with a sandwich composite design of a closed-cell polyurethane foam core with faces constructed of polyester resin infused with glass microspheres was developed. As a basis for comparison, a number of cold-stunned green turtle carcasses were also used in the field experiments. Two vessels, a 5.4 m boat with an inboard jet-drive engine and a 7.3 m boat with an outboard 4-bladed propeller, were operated at planing speed, 40 km/h. The field test results revealed similar patterns and severity of injuries between the synthetic turtles and the green turtle carcasses. Statistical analysis of the field test results indicated the influence of hull type alone on the severity of turtle damage was minimal, and none of the tests conducted using a jet drive engine resulted in injuries to the shell that would be considered lethal, regardless of the vessel hull type, speed, or the animal's depth in the water at impact. Conversely, injuries occurring as a result of propeller and/or skeg impact at planing speed were always classified as fatal. A finite element analysis of the artificial turtle was performed to determine the force at which a carapace fractures from hull impact alone. The results of the finite element analysis suggest that hull impacts of common recreational jet-propulsion vessels are unlikely to cause lethal carapace fractures in loggerhead sea turtles.
Advisors/Committee Members: Scott, David (Committee Chair), Kyum%22%29&pagesize-30">
Choi,
Seung-
Kyum (Committee Member),
Jacobs, Laurence (Committee Member),
Kurtis, Kimberly (Committee Member),
Work, Paul (Committee Member).
Subjects/Keywords: Loggerhead; Vessel strikes; Sea turtle; Loggerhead turtle; Endangered species; Wildlife recovery
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APA (6th Edition):
Spurlock, C. M. (2012). Influence of hull configuration and vessel propulsion systems on sea turtle shell injuries. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/44886
Chicago Manual of Style (16th Edition):
Spurlock, Chad M. “Influence of hull configuration and vessel propulsion systems on sea turtle shell injuries.” 2012. Doctoral Dissertation, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/44886.
MLA Handbook (7th Edition):
Spurlock, Chad M. “Influence of hull configuration and vessel propulsion systems on sea turtle shell injuries.” 2012. Web. 15 Jan 2021.
Vancouver:
Spurlock CM. Influence of hull configuration and vessel propulsion systems on sea turtle shell injuries. [Internet] [Doctoral dissertation]. Georgia Tech; 2012. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/44886.
Council of Science Editors:
Spurlock CM. Influence of hull configuration and vessel propulsion systems on sea turtle shell injuries. [Doctoral Dissertation]. Georgia Tech; 2012. Available from: http://hdl.handle.net/1853/44886
16.
Patel, Jiten.
Enhanced classification approach with semi-supervised learning for reliability-based system design.
Degree: PhD, Mechanical Engineering, 2012, Georgia Tech
URL: http://hdl.handle.net/1853/44872
► Traditionally design engineers have used the Factor of Safety method for ensuring that designs do not fail in the field. Access to advanced computational tools…
(more)
▼ Traditionally design engineers have used the Factor of Safety method for ensuring that designs do not fail in the field. Access to advanced computational tools and resources have made this process obsolete and new methods to introduce higher levels of reliability in an engineering systems are currently being investigated. However, even though high computational resources are available the computational resources required by reliability analysis procedures leave much to be desired. Furthermore, the regression based surrogate modeling techniques fail when there is discontinuity in the design space, caused by failure mechanisms, when the design is required to perform under severe externalities. Hence, in this research we propose efficient Semi-Supervised Learning based surrogate modeling techniques that will enable accurate estimation of a system's response, even under discontinuity. These methods combine the available set of labeled dataset and unlabeled dataset and provide better models than using labeled data alone. Labeled data is expensive to obtain since the responses have to be evaluated whereas unlabeled data is available in plenty, during reliability estimation, since the PDF information of uncertain variables is assumed to be known. This superior performance is gained by combining the efficiency of Probabilistic Neural Networks (PNN) for classification and Expectation-Maximization (EM) algorithm for treating the unlabeled data as labeled data with hidden labels.
Advisors/Committee Members: Kyum%22%29&pagesize-30">
Choi,
Seung-
Kyum (Committee Chair),
Ellingwood, Bruce (Committee Member),
Muhanna, Rafi (Committee Member),
Neu, Richard (Committee Member),
Rosen, David (Committee Member).
Subjects/Keywords: Labeled and unlabeled data; Semi-supervised learning; Probability of failure; Structural reliability; System design; Classification; Safety factor in engineering; Reliability (Engineering); Surrogate-based optimization; Supervised learning (Machine learning); Expectation-maximization algorithms
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APA (6th Edition):
Patel, J. (2012). Enhanced classification approach with semi-supervised learning for reliability-based system design. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/44872
Chicago Manual of Style (16th Edition):
Patel, Jiten. “Enhanced classification approach with semi-supervised learning for reliability-based system design.” 2012. Doctoral Dissertation, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/44872.
MLA Handbook (7th Edition):
Patel, Jiten. “Enhanced classification approach with semi-supervised learning for reliability-based system design.” 2012. Web. 15 Jan 2021.
Vancouver:
Patel J. Enhanced classification approach with semi-supervised learning for reliability-based system design. [Internet] [Doctoral dissertation]. Georgia Tech; 2012. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/44872.
Council of Science Editors:
Patel J. Enhanced classification approach with semi-supervised learning for reliability-based system design. [Doctoral Dissertation]. Georgia Tech; 2012. Available from: http://hdl.handle.net/1853/44872
17.
Goulding, Ashley Nelson.
Implementing the materials genome initiative: Best practice for developing meaningful experimental data sets in aluminum-zinc-magnesium-copper alloys.
Degree: PhD, Materials Science and Engineering, 2016, Georgia Tech
URL: http://hdl.handle.net/1853/55016
► The Materials Genome Initiative was announced by the White House in June of 2011, and is a multi-agency initiative which calls the materials community to…
(more)
▼ The Materials Genome Initiative was announced by the White House in June of 2011, and is a multi-agency initiative which calls the materials community to find ways to discover, develop, manufacture, and deploy advanced materials systems faster and more cost-efficiently. Currently, the amount of time it takes to discover and develop a new material system, optimize its properties, integrate it in to a system, certify that system, and develop the manufacturing capability so that it can be deployed in a commercial component takes at least 20 years. Since this trend holds regardless of the material system in question, the implication is that it is the process by which we as a community move through these seven steps, which causes the lengthy timeline. Historically, the discovery, development, and property optimization of a material system relies heavily on deep scientific knowledge, intuition and trial-and-error physical experimentation. Therefore much of the design and testing of materials in these early stages is currently performed through time-consuming and repetitive experimental and characterization feedback loops. Some of these feedback loops could be eliminated in the property optimization step with improved powerful and accurate computational modeling tools. However, while the ability of computational models to be used in this way is not new, models that have been developed in this space have consistently underperformed. Oftentimes, these models fail because they fail to accurately account for the various physical and chemical mechanisms that are driving the system, or because they fail to account for all of the variables which must be included. Here we propose a standard method of communication for these relationships in the form a process-structure-property-performance map, which leverages the known knowledge database of the material system to clearly and visually communicate the relevant variables and their various relationships in a defined materials design space. Such a map is developed here for high-strength Al-Zn-Mg-Cu alloys, which offer a good example of a material system which could benefit from such a standard. This class of alloys, which are typically utilized in aircraft components, have been incorporated in commercial components for nearly 75 years, and due to its long history is a well characterized and well developed system that is highly suited to this kind of examination. In Part I of this work, we develop this standard by first examining the known knowledge database in this system to deduce what the important process, microstructure, and mechanical property variables are that are of interest. Once these variables and the relationships between them are identified, they are organized into a PSPP map according to a proposed set of steps, and can act as a visual standard that can clearly communicate critical information about the mechanisms of the system. For example, if a model developed within this system does not include a variable or a mechanism depicted within the map, it can be used to…
Advisors/Committee Members: Neu, Richard W. (advisor), Sanders, Tom H. (advisor), McDowell, David L. (committee member), Singh, Preet (committee member), Kyum%22%29&pagesize-30">
Choi,
Seung-
Kyum (committee member).
Subjects/Keywords: Materials genome initiative; Aluminum; Process-structure-property relations
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APA (6th Edition):
Goulding, A. N. (2016). Implementing the materials genome initiative: Best practice for developing meaningful experimental data sets in aluminum-zinc-magnesium-copper alloys. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/55016
Chicago Manual of Style (16th Edition):
Goulding, Ashley Nelson. “Implementing the materials genome initiative: Best practice for developing meaningful experimental data sets in aluminum-zinc-magnesium-copper alloys.” 2016. Doctoral Dissertation, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/55016.
MLA Handbook (7th Edition):
Goulding, Ashley Nelson. “Implementing the materials genome initiative: Best practice for developing meaningful experimental data sets in aluminum-zinc-magnesium-copper alloys.” 2016. Web. 15 Jan 2021.
Vancouver:
Goulding AN. Implementing the materials genome initiative: Best practice for developing meaningful experimental data sets in aluminum-zinc-magnesium-copper alloys. [Internet] [Doctoral dissertation]. Georgia Tech; 2016. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/55016.
Council of Science Editors:
Goulding AN. Implementing the materials genome initiative: Best practice for developing meaningful experimental data sets in aluminum-zinc-magnesium-copper alloys. [Doctoral Dissertation]. Georgia Tech; 2016. Available from: http://hdl.handle.net/1853/55016
18.
Cho, HwanJune.
Uncertainty management in prognosis of electric vehicle energy system.
Degree: PhD, Electrical and Computer Engineering, 2018, Georgia Tech
URL: http://hdl.handle.net/1853/60797
► The body of work described here seeks to understand uncertainties that are inherent in the system prognosis procedure, to represent and propagate them, and to…
(more)
▼ The body of work described here seeks to understand uncertainties that are inherent in the system prognosis procedure, to represent and propagate them, and to manage or shrink uncertainty distribution bounds under long-term and usage-based prognosis for accurate and precise results. Uncertainty is an inherent attribute of prognostic technologies, in which we estimate the End-Of-Life (EOL) and Remaining-Useful-Life (RUL) of a failing component or system, with the time evolution of the incipient failure increasing the uncertainty bounds as the fault horizon also increases. In the given testbed case, the life of the electric vehicle energy system is not measurable. It is only estimated, thereby increasing the importance of uncertainty management. Therefore, methods are needed to handle this uncertainty appropriately in order to improve the accuracy and precision of prognosis via shrinking the uncertainty bounds. To this end, this thesis introduces novel methodologies for the RUL prognosis then the enabling technologies build upon a three-tiered architecture that aims to shrink EOL/RUL bounds: uncertainty representation, uncertainty propagation, and uncertainty management.
Advisors/Committee Members: Vachtsevanos, George (advisor), Bennett, Gisele (committee member), Vela, Patricio Antonio (committee member), Durgin, Gregory David (committee member), Kyum%22%29&pagesize-30">
Choi,
Seung-
Kyum (committee member).
Subjects/Keywords: RUL; EOL; Uncertainty; Electric vehicle energy system; Electric vehicle traction systems; Prognosis
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APA (6th Edition):
Cho, H. (2018). Uncertainty management in prognosis of electric vehicle energy system. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/60797
Chicago Manual of Style (16th Edition):
Cho, HwanJune. “Uncertainty management in prognosis of electric vehicle energy system.” 2018. Doctoral Dissertation, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/60797.
MLA Handbook (7th Edition):
Cho, HwanJune. “Uncertainty management in prognosis of electric vehicle energy system.” 2018. Web. 15 Jan 2021.
Vancouver:
Cho H. Uncertainty management in prognosis of electric vehicle energy system. [Internet] [Doctoral dissertation]. Georgia Tech; 2018. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/60797.
Council of Science Editors:
Cho H. Uncertainty management in prognosis of electric vehicle energy system. [Doctoral Dissertation]. Georgia Tech; 2018. Available from: http://hdl.handle.net/1853/60797
19.
Liu, Yitao.
Game theoretic optimization for high variety assembly system design.
Degree: PhD, Mechanical Engineering, 2016, Georgia Tech
URL: http://hdl.handle.net/1853/56263
► Continuous growing demands of customized products, increasing competition among manufacturing industries and increasing labor cost are demanding mass customization to be realized in all spectrum…
(more)
▼ Continuous growing demands of customized products, increasing competition among
manufacturing industries and increasing labor cost are demanding mass customization to be
realized in all spectrum of industry. However, mass customization has largely not lived up to its
promise. The assembly system, being identified as the breaking point to enable mass
customization, also bring challenges when dealing with high variety products which is typical
situation in mass customization. The topic of this dissertation is identified as game theoretic
optimization for high variety assembly system design. It suggests itself as a key enabler of mass
customization paradigm, which should allow companies to supply high variety product for
today’s market that demands customization without too much tradeoff. The proposed work is
geared towards a game theory based solution to solve complex engineering system design problem, and using the high variety assembly system design as an example. The dissertation
reveals the fundamental issues underlying high variety assembly system design and decision
making in complex engineered systems. In order to tackle the fundamental issues, a technical
framework of game theoretic optimization of high variety assembly system design is proposed. Accordingly, mathematical and computational models are developed within the framework to
support 1) variety propagation from product to assembly process, 2) assembly system layout
design, 3) assembly process design and resource allocation, and 4) assembly process planning.
Advisors/Committee Members: Jiao, Jianxin (advisor), Kyum%22%29&pagesize-30">
Choi,
Seung-
Kyum (committee member),
Wang, Yan (committee member),
Fu, Katherine (committee member),
Hora, Manpreet S. (committee member).
Subjects/Keywords: Game theory; Bi-level; Assembly system; High variety; High mix; Joint optimization; Genetic algorithm; Layout design; Process variety; Product variety; Modular design; Mass customization; Product family design
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APA (6th Edition):
Liu, Y. (2016). Game theoretic optimization for high variety assembly system design. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/56263
Chicago Manual of Style (16th Edition):
Liu, Yitao. “Game theoretic optimization for high variety assembly system design.” 2016. Doctoral Dissertation, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/56263.
MLA Handbook (7th Edition):
Liu, Yitao. “Game theoretic optimization for high variety assembly system design.” 2016. Web. 15 Jan 2021.
Vancouver:
Liu Y. Game theoretic optimization for high variety assembly system design. [Internet] [Doctoral dissertation]. Georgia Tech; 2016. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/56263.
Council of Science Editors:
Liu Y. Game theoretic optimization for high variety assembly system design. [Doctoral Dissertation]. Georgia Tech; 2016. Available from: http://hdl.handle.net/1853/56263
20.
Shin, Jiuk.
Multi-hazard performance criteria for non-ductile reinforced concrete frame buildings retrofitted with an FRP column jacketing system.
Degree: PhD, Civil and Environmental Engineering, 2017, Georgia Tech
URL: http://hdl.handle.net/1853/58728
► Many existing reinforced concrete building structures designed in accordance with pre-1971 codes have non-seismic detailing, which can lead to premature failure under natural and man-made…
(more)
▼ Many existing reinforced concrete building structures designed in accordance with pre-1971 codes have non-seismic detailing, which can lead to premature failure under natural and man-made disasters (e.g. earthquakes and blast events). The premature failure can potentially be prevented through the installation of a fiber-reinforced polymer (FRP) column jacketing system. This retrofit system can be used to ensure that existing structures have adequate seismic and blast performance levels as specified in current design codes. However, code-defined performance criteria are composed of different structural demand limits depending on the loading type. These different demand limits may lead to retrofit designs that are insufficient for multi-hazard loading or overly conservative and therefore not cost-effective. The objective of this dissertation is to propose a multi-hazard performance criteria with energy-based damage limits for non-ductile reinforced concrete frames retrofitted with fiber-reinforced polymer jacketing systems. This study performed a series of full-scale seismic dynamic experiments on a non-ductile reinforced concrete test frame retrofitted with a fiber-reinforced polymer jacketing system to measure the seismic response and quantify the effectiveness of the retrofit system. The measured dynamic responses are utilized to propose and verify a seismic modeling methodology that represents a realistic assessment of bond-slip effects between reinforcing bars and the surrounding concrete. Additionally, a blast modeling methodology, which includes bond-slip effects and an advanced blast load modeling technique, was verified with the experimental responses from previous research. The finite element models are incorporated into the development of fast running models using an artificial neural network. Finally, a multi-hazard performance criteria integrating the energy-based damage demands is derived using the fast running models to determine seismic and blast damage limits corresponding to code-defined performance levels. This multi-hazard criteria is used to develop an effective retrofit design for an FRP column jacketing system under specific seismic and blast loads.
Advisors/Committee Members: Scott, David W. (advisor), Stewart, Lauren K. (committee member), DesRoches, Reginald (committee member), Kyum%22%29&pagesize-30">
Choi,
Seung-
Kyum (committee member),
Yang, Chuang-Sheng (committee member).
Subjects/Keywords: Multi-hazard performance criteria; Non-ductile reinforced concrete frame buildings; Fiber-reinforced polymer column jacketing system; Full-scale dynamic testing; Finite element simulation; Fast running model
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APA (6th Edition):
Shin, J. (2017). Multi-hazard performance criteria for non-ductile reinforced concrete frame buildings retrofitted with an FRP column jacketing system. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/58728
Chicago Manual of Style (16th Edition):
Shin, Jiuk. “Multi-hazard performance criteria for non-ductile reinforced concrete frame buildings retrofitted with an FRP column jacketing system.” 2017. Doctoral Dissertation, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/58728.
MLA Handbook (7th Edition):
Shin, Jiuk. “Multi-hazard performance criteria for non-ductile reinforced concrete frame buildings retrofitted with an FRP column jacketing system.” 2017. Web. 15 Jan 2021.
Vancouver:
Shin J. Multi-hazard performance criteria for non-ductile reinforced concrete frame buildings retrofitted with an FRP column jacketing system. [Internet] [Doctoral dissertation]. Georgia Tech; 2017. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/58728.
Council of Science Editors:
Shin J. Multi-hazard performance criteria for non-ductile reinforced concrete frame buildings retrofitted with an FRP column jacketing system. [Doctoral Dissertation]. Georgia Tech; 2017. Available from: http://hdl.handle.net/1853/58728
Georgia Tech
21.
Gorguluarslan, Recep Muhammet.
A multi-level upscaling and validation framework for uncertainty quantification in additively manufactured lattice structures.
Degree: PhD, Mechanical Engineering, 2016, Georgia Tech
URL: http://hdl.handle.net/1853/56326
► Multiscale modeling techniques are playing an ever increasing role in the effective design of complex engineering systems including aircraft, automobiles, etc. Lightweight cellular lattice structures…
(more)
▼ Multiscale modeling techniques are playing an ever increasing role in the effective design of complex engineering systems including aircraft, automobiles, etc. Lightweight cellular lattice structures (CLSs) gained interest recently since their complex structure, composed of a network of interconnected strut members, can be fabricated by additive manufacturing (AM). However, uncertainties in the fabricated strut members of CLSs are introduced by the layer-by-layer manufacturing process. These fine scale uncertainties influence the overall product performance resulting in inaccurate predictions of reality and increased complexity in simulations. In this research, a multi-level upscaling and validation framework is established that will enable accurate estimation of the performance of AM-fabricated CLSs under uncertainties. An improved stochastic upscaling method based on Polynomial Chaos Expansion (PCE) is employed to quantify and propagate the uncertainties across multiple levels efficiently. The upscaling method is integrated with a hierarchical validation approach to ensure that accurate predictions are made with the homogenized models. The u-pooling method is incorporated with the Kolmogorov-Smirnov test as the validation metric to efficiently use the limited experimental data during validation. The framework is applied to representative examples to demonstrate its efficacy in accurately characterizing the elastic properties of CLSs under uncertainties. The framework is also used to show its applicability in designing CLSs under uncertainties without the use of expensive simulations and optimization processes. The proposed framework is generalized to apply to any complex engineering structure that incorporates computationally intensive simulations and/or expensive experiments associated with fine scale uncertainties.
Advisors/Committee Members: Kyum%22%29&pagesize-30">
Choi,
Seung-
Kyum (advisor),
Rosen, David W. (committee member),
McDowell, David L. (committee member),
Saldana, Christopher J. (committee member),
Muhanna, Rafi L. (committee member).
Subjects/Keywords: Uncertainty quantification; Additive manufacturing; Cellular lattice structure; Validation
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APA (6th Edition):
Gorguluarslan, R. M. (2016). A multi-level upscaling and validation framework for uncertainty quantification in additively manufactured lattice structures. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/56326
Chicago Manual of Style (16th Edition):
Gorguluarslan, Recep Muhammet. “A multi-level upscaling and validation framework for uncertainty quantification in additively manufactured lattice structures.” 2016. Doctoral Dissertation, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/56326.
MLA Handbook (7th Edition):
Gorguluarslan, Recep Muhammet. “A multi-level upscaling and validation framework for uncertainty quantification in additively manufactured lattice structures.” 2016. Web. 15 Jan 2021.
Vancouver:
Gorguluarslan RM. A multi-level upscaling and validation framework for uncertainty quantification in additively manufactured lattice structures. [Internet] [Doctoral dissertation]. Georgia Tech; 2016. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/56326.
Council of Science Editors:
Gorguluarslan RM. A multi-level upscaling and validation framework for uncertainty quantification in additively manufactured lattice structures. [Doctoral Dissertation]. Georgia Tech; 2016. Available from: http://hdl.handle.net/1853/56326
Georgia Tech
22.
Kumar, Abhishek.
A tolerance allocation framework using fuzzy comprehensive evaluation and decision support processes.
Degree: MS, Mechanical Engineering, 2010, Georgia Tech
URL: http://hdl.handle.net/1853/37212
► Tolerances play an important role in product fabrication. Tolerances impact the needs of the designer and the manufacturer. Engineering designers are concerned with the impact…
(more)
▼ Tolerances play an important role in product fabrication. Tolerances impact the needs of the designer and the manufacturer. Engineering designers are concerned with the impact of tolerances on the variation of the output, while manufacturers are more concerned with the cost of fitting the parts. Traditional tolerance control methods do not take into account both these needs. In this thesis, the author proposes a framework that overcomes the drawbacks of the traditional tolerance control methods, and reduces subjectivity via fuzzy set theory and decision support systems (DSS). Those factors that affect the manufacturing cost (geometry, material etc) of a part are fuzzy (i.e. subjective) in nature with no numerical measure. Fuzzy comprehensive evaluation (FCE) is utilized in this thesis as a method of quantifying the fuzzy (i.e. subjective) factors. In the FCE process, the weighted importance of each factor affects the manufacturing cost of the part. There is no systematic method of calculating the importance weights. This brings about a need for decision support in the evaluation of the weighted importance of each factor. The combination of FCE and DSS, in the form of Conjoint Analysis (CA), is used to reduce subjectivity in calculation of machining cost. Taguchi's quality loss function is considered in this framework to reduce the variation in the output. The application of the framework is demonstrated with three practical engineering applications. Tolerances are allocated for three assemblies; a friction clutch, an accumulator O-ring seal and a Power Generating Shock Absorber (PGSA) using the proposed framework. The output performances of the PGSA and the clutch are affected by the allocated tolerances. On using the proposed framework, there is seen to be a reduction in variation of output performance for the clutch and the PGSA. The use of CA is also validated by checking efficiency of final tolerance calculation with and without use of CA.
Advisors/Committee Members: Kyum%22%29&pagesize-30">
Choi,
Seung-
Kyum (Committee Chair),
Muhanna, Rafi (Committee Member),
Schaefer, Dirk (Committee Member).
Subjects/Keywords: Tolerance allocation; Fuzzy comprehensive evaluation; Conjoint analysis; O-ring; O-ring seal; Clutch; Power generating shock absorber; Tolerance (Engineering); Fuzzy decision making; Decision support systems
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APA (6th Edition):
Kumar, A. (2010). A tolerance allocation framework using fuzzy comprehensive evaluation and decision support processes. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/37212
Chicago Manual of Style (16th Edition):
Kumar, Abhishek. “A tolerance allocation framework using fuzzy comprehensive evaluation and decision support processes.” 2010. Masters Thesis, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/37212.
MLA Handbook (7th Edition):
Kumar, Abhishek. “A tolerance allocation framework using fuzzy comprehensive evaluation and decision support processes.” 2010. Web. 15 Jan 2021.
Vancouver:
Kumar A. A tolerance allocation framework using fuzzy comprehensive evaluation and decision support processes. [Internet] [Masters thesis]. Georgia Tech; 2010. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/37212.
Council of Science Editors:
Kumar A. A tolerance allocation framework using fuzzy comprehensive evaluation and decision support processes. [Masters Thesis]. Georgia Tech; 2010. Available from: http://hdl.handle.net/1853/37212
Georgia Tech
23.
Ruderman, Alex Michael.
A framework for simulation-based multi-attribute optimum design with improved conjoint analysis.
Degree: MS, Mechanical Engineering, 2009, Georgia Tech
URL: http://hdl.handle.net/1853/31811
► Decision making is necessary to provide a synthesis scheme to design activities and identify the most preferred design alternative. There exist several methods that address…
(more)
▼ Decision making is necessary to provide a synthesis scheme to design activities and identify the most preferred design alternative. There exist several methods that address modeling designer preferences in a graphical manner to aid the decision making process. For instance, the Conjoint Analysis has been proven effective for various multi-attribute design problems by utilizing a ranking- or rating-based approach along with the graphical representation of the designer preference. However, the ranking or rating of design alternatives can be inconsistent from different users and it is often difficult to get customer responses in a timely fashion. The high number of alternative comparisons required for complex engineering problems can be exhausting for the decision maker. In addition, many design objectives can have interdependencies that can increase complexity and uncertainty throughout the decision making process. The uncertainties apparent in the attainment of subjective data as well as with system models can reduce the reliability of decision analysis results. To address these issues, the use of a new technique, the Improved Conjoint Analysis, is proposed to enable the modeling of designer preferences and trade-offs under the consideration of uncertainty. Specifically, a simulation-based ranking scheme is implemented and incorporated into the traditional process of the Conjoint Analysis. The proposed ranking scheme can reduce user fatigue and provide a better schematic decision support process. In addition, the incorporation of uncertainty in the design process provides the capability of producing robust or reliable products. The efficacy and applicability of the proposed framework are demonstrated with the design of a cantilever beam, a power-generating shock absorber, and a mesostructured hydrogen storage tank.
Advisors/Committee Members: Kyum%22%29&pagesize-30">
Choi,
Seung-
Kyum (Committee Chair),
Allen, Janet K. (Committee Member),
Paredis, Chris (Committee Member).
Subjects/Keywords: Conjoint analysis; Optimization; Multi-attribute decision analysis; Multidisciplinary design optimization; Conjoint analysis (Marketing); Uncertainty (Information theory); Multiple criteria decision making
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Export
to Zotero / EndNote / Reference
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APA (6th Edition):
Ruderman, A. M. (2009). A framework for simulation-based multi-attribute optimum design with improved conjoint analysis. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/31811
Chicago Manual of Style (16th Edition):
Ruderman, Alex Michael. “A framework for simulation-based multi-attribute optimum design with improved conjoint analysis.” 2009. Masters Thesis, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/31811.
MLA Handbook (7th Edition):
Ruderman, Alex Michael. “A framework for simulation-based multi-attribute optimum design with improved conjoint analysis.” 2009. Web. 15 Jan 2021.
Vancouver:
Ruderman AM. A framework for simulation-based multi-attribute optimum design with improved conjoint analysis. [Internet] [Masters thesis]. Georgia Tech; 2009. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/31811.
Council of Science Editors:
Ruderman AM. A framework for simulation-based multi-attribute optimum design with improved conjoint analysis. [Masters Thesis]. Georgia Tech; 2009. Available from: http://hdl.handle.net/1853/31811
Georgia Tech
24.
Engelbrecht, Sarah.
Design of meso-scale cellular structure for rapid manufacturing.
Degree: MS, Mechanical Engineering, 2009, Georgia Tech
URL: http://hdl.handle.net/1853/33876
► Customized cellular material is a relatively new area made possible by advancements in rapid manufacturing technologies. Rapid manufacturing is ideal for the production of customized…
(more)
▼ Customized cellular material is a relatively new area made possible by advancements in rapid manufacturing technologies. Rapid manufacturing is ideal for the production of customized cellular structure, especially on the meso scale, due to the size and complexity of the design. The means to produce this type of structure now exist, but the processes to design the structure are not well developed. The manual design of customized cellular material is not realistic due to the large number of features. Currently there are few tools available that aid in the design of this type of material. In this thesis, an automated tool to design customized cellular structure is presented.
Advisors/Committee Members: Rosen, David (Committee Chair), Kyum%22%29&pagesize-30">
Choi,
Seung-
Kyum (Committee Member),
Sitaraman, Suresh (Committee Member).
Subjects/Keywords: Meso-scale; Rapid manufacturing; Lattice; Truss; Cellular structure; SLA; SLS; Manufacturing processes; Manufacturing cells; Rapid prototyping
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APA (6th Edition):
Engelbrecht, S. (2009). Design of meso-scale cellular structure for rapid manufacturing. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/33876
Chicago Manual of Style (16th Edition):
Engelbrecht, Sarah. “Design of meso-scale cellular structure for rapid manufacturing.” 2009. Masters Thesis, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/33876.
MLA Handbook (7th Edition):
Engelbrecht, Sarah. “Design of meso-scale cellular structure for rapid manufacturing.” 2009. Web. 15 Jan 2021.
Vancouver:
Engelbrecht S. Design of meso-scale cellular structure for rapid manufacturing. [Internet] [Masters thesis]. Georgia Tech; 2009. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/33876.
Council of Science Editors:
Engelbrecht S. Design of meso-scale cellular structure for rapid manufacturing. [Masters Thesis]. Georgia Tech; 2009. Available from: http://hdl.handle.net/1853/33876
Georgia Tech
25.
Chu, Chen.
Design synthesis for morphing 3D meso-scale structure.
Degree: MS, Mechanical Engineering, 2009, Georgia Tech
URL: http://hdl.handle.net/1853/34676
► Rapid prototyping (RP) can be used to make complex shapes with very little or even no constraint on the form of the parts. New design…
(more)
▼ Rapid prototyping (RP) can be used to make complex shapes with very little or even no constraint on the form of the parts. New design methods are needed for parts that can take advantage of the unique capabilities of RP. Although current synthesis methods can successfully solve simple design problems, practical applications with thousands to millions elements are prohibitive to generate solution for.
Two factors are considered. One is the number of design variables; the other is the optimization method. To reduce the number of design variables, parametric approach is introduced. Control diameters are used to control all strut size across the entire structure by utilizing a concept similar to control vertices and Bezier surface. This operation allows the number of design variables to change from the number of elements to a small set of coefficients.
In lattice structure design, global optimization methods are popular and widely used. These methods use heuristic strategies to search the design space and thus perform, as oppose to traditional mathematical programming (MP) methods, a better global search. This work propose that although traditional MP methods find local optimum near starting point, given a quick convergence rate, it will be more efficient to perform such method multiple times to integrate global search than using a global optimization method. Particle Swarm Optimization and Levenburg-Marquardt are chosen to perform the experiments.
Advisors/Committee Members: Rosen, David (Committee Chair), Kyum%22%29&pagesize-30">
Choi,
Seung-
Kyum (Committee Member),
Hague, Richard (Committee Member).
Subjects/Keywords: Design synthesis method; Optimization; Parametric approach; Compliant mechanism; Meso-scale cellular structures; Rapid prototyping
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APA (6th Edition):
Chu, C. (2009). Design synthesis for morphing 3D meso-scale structure. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/34676
Chicago Manual of Style (16th Edition):
Chu, Chen. “Design synthesis for morphing 3D meso-scale structure.” 2009. Masters Thesis, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/34676.
MLA Handbook (7th Edition):
Chu, Chen. “Design synthesis for morphing 3D meso-scale structure.” 2009. Web. 15 Jan 2021.
Vancouver:
Chu C. Design synthesis for morphing 3D meso-scale structure. [Internet] [Masters thesis]. Georgia Tech; 2009. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/34676.
Council of Science Editors:
Chu C. Design synthesis for morphing 3D meso-scale structure. [Masters Thesis]. Georgia Tech; 2009. Available from: http://hdl.handle.net/1853/34676
Georgia Tech
26.
Moore, Roxanne Adele.
Variable fidelity modeling as applied to trajectory optimization for a hydraulic backhoe.
Degree: MS, Mechanical Engineering, 2009, Georgia Tech
URL: http://hdl.handle.net/1853/28146
► Modeling, simulation, and optimization play vital roles throughout the engineering design process; however, in many design disciplines the cost of simulation is high, and designers…
(more)
▼ Modeling, simulation, and optimization play vital roles throughout the engineering design process; however, in many design disciplines the cost of simulation is high, and designers are faced with a tradeoff between the number of alternatives that can be evaluated and the accuracy with which they can be evaluated. In this thesis, a methodology is presented for using models of various levels of fidelity during the optimization process. The intent is to use inexpensive, low-fidelity models with limited accuracy to recognize poor design alternatives and reserve the high-fidelity, accurate, but also expensive models only to characterize the best alternatives. Specifically, by setting a user-defined performance threshold, the optimizer can explore the design space using a low-fidelity model by default, and switch to a higher fidelity model only if the performance threshold is attained. In this manner, the high fidelity model is used only to discern the best solution from the set of good solutions, so that computational resources are conserved until the optimizer is close to the solution. This makes the optimization process more efficient without sacrificing the quality of the solution. The method is illustrated by optimizing the trajectory of a hydraulic backhoe. To characterize the robustness and efficiency of the method, a design space exploration is performed using both the low and high fidelity models, and the optimization problem is solved multiple times using the variable fidelity framework.
Advisors/Committee Members: Paredis, Chris (Committee Chair), Bras, Bert (Committee Member), Burkhart, Roger (Committee Member), Kyum%22%29&pagesize-30">
Choi,
Seung-
Kyum (Committee Member).
Subjects/Keywords: Modeling; Variable-fidelity; Simulation; Optimization; Backhoe; Fluid power; Hydrualics; Backhoes; Trajectory optimization
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Manager
APA (6th Edition):
Moore, R. A. (2009). Variable fidelity modeling as applied to trajectory optimization for a hydraulic backhoe. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/28146
Chicago Manual of Style (16th Edition):
Moore, Roxanne Adele. “Variable fidelity modeling as applied to trajectory optimization for a hydraulic backhoe.” 2009. Masters Thesis, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/28146.
MLA Handbook (7th Edition):
Moore, Roxanne Adele. “Variable fidelity modeling as applied to trajectory optimization for a hydraulic backhoe.” 2009. Web. 15 Jan 2021.
Vancouver:
Moore RA. Variable fidelity modeling as applied to trajectory optimization for a hydraulic backhoe. [Internet] [Masters thesis]. Georgia Tech; 2009. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/28146.
Council of Science Editors:
Moore RA. Variable fidelity modeling as applied to trajectory optimization for a hydraulic backhoe. [Masters Thesis]. Georgia Tech; 2009. Available from: http://hdl.handle.net/1853/28146
. 
Open Access Theses and Dissertations
