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Mechanical Engineering Commons™

Open Access. Powered by Scholars. Published by Universities.®

2015

Clemson University

All Theses

Articles 1 - 9 of 9

Full-Text Articles in Mechanical Engineering

Experimental Investigation Of Heat Leakage And Air Leakage In Domestic Refrigerators, Shervin Shoai Naini Dec 2015

Experimental Investigation Of Heat Leakage And Air Leakage In Domestic Refrigerators, Shervin Shoai Naini

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The optimization of the energy consumption in household refrigerators should consider the influence of the gasket which determines the heat transfer and air infiltration rate. In this research project, engineering methods are developed to evaluate the heat leakage due to the gasket and air infiltration in domestic refrigerators. In the first study, experimental and numerical approaches are applied to evaluate the gasket heat transfer based on the “Reverse Heat Load Method”. The main objective is to find the effective heat leakage with the dimensions of energy leakage per gasket length per temperature difference (W/m.K). An insulated cubic box with a …

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Co-Design Of Dynamic Real-Time Scheduling And Cooperative Control For Human-Agent Collaboration Systems Based On Mutual Trust, Xiaotian Wang Dec 2015

Co-Design Of Dynamic Real-Time Scheduling And Cooperative Control For Human-Agent Collaboration Systems Based On Mutual Trust, Xiaotian Wang

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Mutual trust is a key factor in human-human collaboration. Inspired by this social interaction, we analyze human-agent mutual trust in the collaboration of one human and (semi)autonomous multi-agent systems. In the thesis, we derive time-series human-agent mutual trust models based on results from human factors engineering. To avoid both over- trust and under-trust, we set up dynamic timing models for the multi-agent scheduling problem and develop necessary and sufficient conditions to test the schedulability of the human multi-agent collaborative task. Furthermore, we extend the collaboration between one human and multiple agents into the collaboration between multi-human network and swarm-based agents …

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Structural Optimization Using Parametric Programming Method, Krupakaran Ravichandraan Dec 2015

Structural Optimization Using Parametric Programming Method, Krupakaran Ravichandraan

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The Parametric Programming method is investigated to consider its applicability to structural optimization problems. It is used to solve optimization problems that have design variables as implicit functions of some independent input parameter(s). It provides optimal solutions as a parametric function of the input parameter(s) for the entire parameter space of interest. It does not require the detailed discrete optimizations needed at a large number of parameter values as in traditional non-parametric optimization. Parametric programming is widely used in optimal controls, model predictive control, scheduling, process synthesis and material design under uncertainty due to the above mentioned benefits. Its benefits …

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A Novel Approach To Evaluating Compact Finite Differences And Similar Tridiagonal Schemes On Gpu-Accelerated Clusters, Ashwin Trikuta Srinath Dec 2015

A Novel Approach To Evaluating Compact Finite Differences And Similar Tridiagonal Schemes On Gpu-Accelerated Clusters, Ashwin Trikuta Srinath

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Compact finite difference schemes are widely used in the direct numerical simulation of fluid flows for their ability to better resolve the small scales of turbulence. However, they can be expensive to evaluate and difficult to parallelize. In this work, we present an approach for the computation of compact finite differences and similar tridiagonal schemes on graphics processing units (GPUs). We present a variant of the cyclic reduction algorithm for solving the tridiagonal linear systems that arise in such numerical schemes. We study the impact of the matrix structure on the cyclic reduction algorithm and show that precomputing forward reduction …

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Design Of A Meta-Material With Targeted Nonlinear Deformation Response, Zachary Satterfield Dec 2015

Design Of A Meta-Material With Targeted Nonlinear Deformation Response, Zachary Satterfield

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The M1 Abrams tank contains track pads consist of a high density rubber. This rubber fails prematurely due to heat buildup caused by the hysteretic nature of elastomers. It is therefore desired to replace this elastomer by a meta-material that has equivalent nonlinear deformation characteristics without this primary failure mode. A meta-material is an artificial material in the form of a periodic structure that exhibits behavior that differs from its constitutive material. After a thorough literature review, topology optimization was found as the only method used to design meta-materials. Further investigation determined topology optimization as an infeasible method to design …

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Control Of Thermoforming Process Parameters To Manufacture Surfaces With Pin-Based Tooling, Vijay Sarthy Mysore Sreedhara Dec 2015

Control Of Thermoforming Process Parameters To Manufacture Surfaces With Pin-Based Tooling, Vijay Sarthy Mysore Sreedhara

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Many manufacturing processes used to mass produce parts rely on expensive and time consuming tooling. These processes include sheet metal forming, injection molding, casting, and thermoforming. The time invested in design and development of tooling can be justified for high-production volumes. However, for low-volume production and customized products, the tooling investment cannot be amortized. Flexible tooling has been developed to address the needs of smaller production volumes. Reconfigurable pin tooling is an example of flexible tooling that relies on a matrix of adjustable-height pins to produce approximate surfaces. A key challenge in pin-based tooling is achieving accurate high quality surfaces …

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Analysis And Synthesis Of Effective Human-Robot Interaction At Varying Levels In Control Hierarchy, David Spencer Dec 2015

Analysis And Synthesis Of Effective Human-Robot Interaction At Varying Levels In Control Hierarchy, David Spencer

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Robot controller design is usually hierarchical with both high-level task and motion planning and low-level control law design. In the presented works, we investigate methods for low-level and high-level control designs to guarantee joint performance of human-robot interaction (HRI). In the first work, a low-level method using the switched linear quadratic regulator (SLQR), an optimal control policy based on a quadratic cost function, is used. By incorporating measures of robot performance and human workload, it can be determined when to utilize the human operator in a method that improves overall task performance while reducing operator workload. This method is demonstrated …

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A Method For The Characterization And Selection Of Compliant Joints, Ronald George Saleeby May 2015

A Method For The Characterization And Selection Of Compliant Joints, Ronald George Saleeby

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A compliant joint is a connection between two bodies that derives its movement from the deflection of flexible members rather than rigid connections, like traditional joints. Compliant joints have potential advantages that include longer part life, reduction of parts in assemblies, and reduced wear. Traditional compliant mechanism design methodologies have limitations involving the burden of necessary knowledge required to satisfactorily use them. The method presented in this thesis was developed to provide compliant joint design solutions independent of the traditional methods of compliant joint design by allowing the selection of compliant joints from a repository. The repository is populated by …

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Computational Modeling Of Alternating Current Potential Drop Measurement For Crack Detection Of Multi-Functional Ceramic Coated Structures, Simha Sandeep Rao May 2015

Computational Modeling Of Alternating Current Potential Drop Measurement For Crack Detection Of Multi-Functional Ceramic Coated Structures, Simha Sandeep Rao

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Non-destructive testing and evaluation (NDT&E) is a set of techniques commonly used to evaluate a material for the presence of any flaws without actually degrading the material itself. The Alternating Current Potential Drop (ACPD) test method is one of the NDT surface methods used to determine the electrically insulating defects beneath the surface by injection of currents in the structure and measurement of the resulting voltage difference between two or more points on the surface. The presence of defects generally increases the resistance of the structure and hence causes the drop of measured voltage. The inversion of this data can …

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