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Full-Text Articles in Mechanical Engineering

Detection And Classification Of Vibrating Objects In Sar Images, Francisco German Perez Venegas Apr 2019

Detection And Classification Of Vibrating Objects In Sar Images, Francisco German Perez Venegas

Electrical and Computer Engineering ETDs

The vibratory response of buildings and machines contains key information that can be exploited to infer their operating conditions and to diagnose failures. Furthermore, since vibration signatures observed from the exterior surfaces of structures are intrinsically linked to the type of machinery operating inside of them, the ability to monitor vibrations remotely can enable the detection and identification of the machinery.

This dissertation focuses on developing novel techniques for the detection and M-ary classification of vibrating objects in SAR images. The work performed in this dissertation is conducted around three central claims. First, the non-linear transformation that the micro-Doppler return ...


Modeling And Simulation Of The Thermoforming Process In Thermoplastic-Matrix Composite Materials, Philip M. Bean Dec 2018

Modeling And Simulation Of The Thermoforming Process In Thermoplastic-Matrix Composite Materials, Philip M. Bean

Electronic Theses and Dissertations

Thermoplastic-matrix composite materials have unique advantages over traditional thermosets including faster processing, improved fracture toughness, and recyclability. These and other benefits have caused increasing interest in the use of these materials in both aerospace and automotive industries. Due to the differences in behavior, these materials require a different type of manufacturing process to thermoset matrix composites. This manufacturing process generally involves using pre manufactured tape-layers. These layers, containing both thermoplastic-matrix and fiber-reinforcement, are aligned to the desired orientation, and stacked up into a “tailored blank” using an automated tape layup machine. They are then heated to the thermoplastic melting temperature ...


Micro-Manipulation Using Learned Model, Matthew A. Lyng, Benjamin V. Johnson, David J. Cappelleri Aug 2018

Micro-Manipulation Using Learned Model, Matthew A. Lyng, Benjamin V. Johnson, David J. Cappelleri

The Summer Undergraduate Research Fellowship (SURF) Symposium

Microscale devices can be found in applications ranging from sensors to structural components. The dominance of surface forces at the microscale hinders the assembly processes through nonlinear interactions that are difficult to model for automation, limiting designs of microsystems to primarily monolithic structures. Methods for modeling surface forces must be presented for viable manufacturing of devices consisting of multiple microparts. This paper proposes the implementation of supervised machine learning models to aid in automated micromanipulation tasks for advanced manufacturing applications. The developed models use sets of training data to implicitly model surface interactions and predict end-effector placement and paths that ...


Control-Oriented Automatic Transmission- Based Powertrain Modeling And Simulation With Judder, Harshal B. Kundale Aug 2018

Control-Oriented Automatic Transmission- Based Powertrain Modeling And Simulation With Judder, Harshal B. Kundale

Master's Theses

This work presents automatic transmission-based powertrain modeling. The powertrain consists of an engine, torque converter with lock up clutch, transmission gearbox, propeller shaft, and vehicle body. Simplified powertrain component models are developed for vehicle powertrain dynamic response analysis and future control work. The powertrain components are modeled with algebraic and first order non-linear differential equations. A MATLAB-based powertrain simulation system is developed to investigate the transient characteristics during lock up of torque converter. Simulation results are used in the determination of effects of judder on torque and angular velocity. Clutch judder is a self-excited vibration that occurs during the clutch ...


The Design, Modeling, And Optimization Of A Biomimetic Soft Robot For Fluid Pumping And Thrust Generation Using Electroactive Polymer Actuators, Zakai Jedidiah Olsen May 2018

The Design, Modeling, And Optimization Of A Biomimetic Soft Robot For Fluid Pumping And Thrust Generation Using Electroactive Polymer Actuators, Zakai Jedidiah Olsen

UNLV Theses, Dissertations, Professional Papers, and Capstones

Nature is a constant source of inspiration for engineers and scientists through its simple, effective, and elegant solutions to many complex problems. Smart materials and soft robotics have been seen to be particularly well suited for developing biomimetic devices and are active fields of research. In this study, the design, modeling, and optimization of a new biomimetic soft robot is described. Preliminary work was made in the modeling of a biomimetic robot based on the locomotion and kinematics of jellyfish. Modifications were made to the governing equations for jellyfish locomotion that accounted for geometric differences between biology and the robotic ...


Reduced Order Modeling For Virtual Building Commissioning, Sean Rosin May 2018

Reduced Order Modeling For Virtual Building Commissioning, Sean Rosin

Boise State University Theses and Dissertations

Model order reduction can help reduce the time and monetary constraints associated with building commissioning and significantly decrease overall building energy consumption through virtual commissioning. This research aimed to determine the effectiveness of using reduced order models to simulate the overall building energy consumption, and to estimate the energy savings from control-based commissioning recommendations.

A case study building was modeled using a ‘Lumped RC’ thermal model with three thermal resistances and capacitances (3R3C) for the building interior and a 2R1C model describing the building foundation. Due to energy consumption being dependent on building systems, this model was coupled with a ...


Physical Modeling Of Lithium-Ion Aging For Automotive Applications, Anurag Kamal Jan 2018

Physical Modeling Of Lithium-Ion Aging For Automotive Applications, Anurag Kamal

Dissertations, Master's Theses and Master's Reports

This thesis extends the full-scale electrochemical model for a Lithium-ion battery based on the porous electrode theory to incorporate aging mechanisms of solid electrolyte interface formation, cyclic electrode degradation, and lithium plating during overcharge, automotive vibrations, mechanical stress, and cell temperature, as reported in the existing literature. Further, the thesis presents the scope of the parameters used in the model to enable designers to extend the equations for new mechanisms and variability of other parameters.

An increased set of equations makes the complexity of the model even higher, and it would be very computationally complex to simulate this model. This ...


Development Of Novel Models To Study Deep Brain Effects Of Cortical Transcranial Magnetic Stimulation, Farheen Syeda Jan 2018

Development Of Novel Models To Study Deep Brain Effects Of Cortical Transcranial Magnetic Stimulation, Farheen Syeda

Theses and Dissertations

Neurological disorders require varying types and degrees of treatments depending on the symptoms and underlying causes of the disease. Patients suffering from medication-refractory symptoms often undergo further treatment in the form of brain stimulation, e.g. electroconvulsive therapy (ECT), transcranial direct current stimulation (tDCS), deep brain stimulation (DBS), or transcranial magnetic stimulation (TMS). These treatments are popular and have been shown to relieve various symptoms for patients with neurological conditions. However, the underlying effects of the stimulation, and subsequently the causes of symptom-relief, are not very well understood. In particular, TMS is a non-invasive brain stimulation therapy which uses time-varying ...


Large Eddy Simulations Of Industrial Burners, Siddharth Prashant Nigam Jan 2018

Large Eddy Simulations Of Industrial Burners, Siddharth Prashant Nigam

Mechanical Engineering Graduate Theses & Dissertations

During the past four years, a gift from 3M has funded a project that is at the intersection of academia and industry at the University of Colorado, Boulder (CU). The overall objective of this joint computational and experimental effort is to explore optimization and improvement of burner/chilled-roll systems for polymer film flame treatments. Using the computational and experimental tools developed in this project, existing treatment processes will be improved and new avenues of technology innovation will be explored.

In this thesis, industry-relevant heat treatment processes with catalytic and ribbon burners are studied using large eddy simulations (LES). The simulations ...


Effect Of Poisson’S Ratio On Young's Modulus Characterization Using Ultrasonic Technique By Modeling, Michael Onyetube Jan 2018

Effect Of Poisson’S Ratio On Young's Modulus Characterization Using Ultrasonic Technique By Modeling, Michael Onyetube

Electronic Theses and Dissertations

The past 27 years has witnessed a revolutionary growth in the progress of material development and application in almost all industry and business sectors, and this seems to be continuing even today. So many material-driven innovations have enabled the global spread in technology and improvements in capability, ranging from communications to aerospace and healthcare, to automotive and agriculture. Mechanical behavior of elastic materials is modeled by two main independent constants; Young’s modulus and Poisson’s ratio. An accurate measurement of both constants is necessary in most engineering applications, for example, the standard materials used for the calibration of some ...


Development Mems Acoustic Emission Sensors, Adrian Enrique Avila Gomez Nov 2017

Development Mems Acoustic Emission Sensors, Adrian Enrique Avila Gomez

Graduate Theses and Dissertations

The purpose of this research is to develop MEMS based acoustic emission sensors for structural health monitoring. Acoustic emission (AE) is a well-established nondestructive testing technique that is typically used to monitor for fatigue cracks in structures, leaks in pressurized systems, damages in composite materials or impacts. This technology can offer a precise evaluation of structural conditions and allow identification of imminent failures or minor failures that can be addressed by planned maintenances routines. AE causes a burst of ultrasonic energy that is measured as high frequency surface vibrations (30 kHz to 1 MHz) generated by transient elastic waves that ...


Thermoelectric System Modeling And Design, Buddhima Pasindu Gamarachchi Aug 2017

Thermoelectric System Modeling And Design, Buddhima Pasindu Gamarachchi

Boise State University Theses and Dissertations

Thermoelectric generators (TEGs) convert heat to electricity by way of the Seebeck effect. TEGs have no moving parts and are environmentally friendly and can be implemented with systems to recover waste heat. This work examines complete thermoelectric systems, which include the (TEG) and heat exchangers or heat sinks attached to the hot and cold sides of the TEG to maintain the required temperature difference across the TEG. A 1-D steady state model is developed to predict the performance of a TEG given the required temperatures and device dimensions. The model is first validated using a 3-D model and then is ...


The Effect Of Bone And Ligament Morphology Of Ankle Joint Loading In The Neutral Position, Jinhyuk Kim Jul 2017

The Effect Of Bone And Ligament Morphology Of Ankle Joint Loading In The Neutral Position, Jinhyuk Kim

Mechanical & Aerospace Engineering Theses & Dissertations

Computational modeling of joints is used to investigate the effect of injuries, to plan surgeries, and to answer questions about joints that cannot be answered experimentally. Existing models of the ankle joint are moving toward being able to model specific patients, however, they do not include all of the anatomy (e.g., bones and/or ligaments) and have restrictive boundary conditions. These simplification in anatomy are made to minimize pre-processing and computation time. Because biomechanical modeling is increasingly focused on the implementation of patient specific cases, the effects of including more anatomical structures and determining how they affect the model ...


Characterizing The Viscoelastic Behavior Of Pdms/Pdps Copolymers, Mark E. Small Jun 2017

Characterizing The Viscoelastic Behavior Of Pdms/Pdps Copolymers, Mark E. Small

Mechanical Engineering ETDs

Viscoelasticity is the property of materials that exhibits both viscous and elastic characteristics when undergoing deformation. In polymeric materials, the mechani- cal behavior is dominated by this viscoelastic phenomenon. Creating computational models for these materials can be quite complicated due to their frequency depen- dent and temperature dependent material properties. The research presented in this paper will use state of the art methods to fully develop a material model for a filled polydimethylsiloxane-polydiphenynlsiloxane (PDMS/PDPS) copolymer foam that has yet to be characterized. Mechanical properties of PDMS/PDPS copoly- mers are currently being studied to assess engineering performance, and to ...


Modeling Of Selective Laser Sintering/ Selective Laser Melting, Xuan Wang, Connor West Jan 2017

Modeling Of Selective Laser Sintering/ Selective Laser Melting, Xuan Wang, Connor West

Industrial and Manufacturing Engineering

Selective laser sintering and selective laser melting are powder based additive manufacturing (AM) process that can rapidly manufacture parts with comparable mechanical properties to conventional manufacturing methods directly from digital files. However, the processing recipe development and design optimization of AM parts are often based on trial and error which erodes the benefit of AM. Modeling is a powerful tool to enable faster development cycle by significantly reducing the experimental efforts. In this paper we discussed the current status of selective laser sintering/melting modeling, in which the laser and powder interaction was studied to understand and predict the process ...


Turbulent Spray Combustion Modeling Using Direct Integration Of Chemistry And Flamelet Generated Manifolds, Ashraya Goyal Jan 2017

Turbulent Spray Combustion Modeling Using Direct Integration Of Chemistry And Flamelet Generated Manifolds, Ashraya Goyal

Wayne State University Theses

Turbulent spray combustion of n-dodecane was modeled at engine relevant conditions using various combustion models (Direct Integration of Chemistry and Flamelet Generated Manifolds) and turbulence models (Dynamic Structure Large Eddy Simulation and RNG Reynolds-Averaged Naiver-Stokes). A recently developed n-dodecane mechanism was utilized and the turbulent spray was simulated at various combustion chamber initial gas temperature and pressure conditions. Mesh with size of 31 microns was utilized to resolve small eddies around the spray. The pressure-based ignition delay, flame lift-off length, and spray and jet penetrations were studied and compared with experimental measurements. The Direct Integration of Chemistry and Flamelet Generated ...


Statistical Shape Modeling To Quantify Variation In The Proximal Humeral Anatomy, Paul B. Sade Sr. Jan 2017

Statistical Shape Modeling To Quantify Variation In The Proximal Humeral Anatomy, Paul B. Sade Sr.

Electronic Theses and Dissertations

The fit of the humeral prosthesis to the intramedullary canal and the replication of the anatomic humeral head center are important factors in Total Shoulder Arthroplasty (TSA). The objective of this thesis was to develop a Statistical Shape Model (SSM) of the cortical and cancellous bone regions of the proximal humerus, and to assess potential shape differences with gender and ethnicity, with a goal of informing implant design. An SSM was used and Principal Component Analysis (PCA) was applied to data that represented both the cancellous and cortical humeral bone of 63 healthy subjects and cadavers. Anatomical measurements and PC ...


Evaluating The Performance Of Passive Chilled Beams With Respect To Energy Efficiency And Thermal Comfort, Janghyun Kim Dec 2016

Evaluating The Performance Of Passive Chilled Beams With Respect To Energy Efficiency And Thermal Comfort, Janghyun Kim

Open Access Dissertations

Existing modeling approaches for passive chilled beams determined from tests on individual chilled beams in a laboratory are not adequate for assessing overall energy usage and occupant comfort within building simulation programs. In addition, design guidelines for passive chilled beam systems are needed for identifying appropriate applications and optimal configurations. This thesis includes (i) extensive experimental studies for characterizing the performance of passive chilled beams, in both laboratory settings and in field studies, (ii) development of passive chilled beam performance prediction models, (iii) integration of these models into building simulation models/tools and (iv) use of building simulation for overall ...


Fundamental Studies Of Electrochemical Reactions And Microfluidics In Proton Exchange Membrane Electrolyzer Cells, Jingke Mo Dec 2016

Fundamental Studies Of Electrochemical Reactions And Microfluidics In Proton Exchange Membrane Electrolyzer Cells, Jingke Mo

Doctoral Dissertations

In electrochemical energy devices, including fuel cells, electrolyzers and batteries, the electrochemical reactions occur only on triple phase boundaries (TPBs). The boundaries provide the conductors for electros and protons, the catalysts for electrochemical reactions and the effective pathways for transport of reactants and products. The interfaces have a critical impact on the overall performance and cost of the devices in which they are incorporated, and therefore could be a key feature to optimize in order to turn a prototype into a commercially viable product. For electrolysis of water, proton exchange membrane electrolyzer cells (PEMECs) have several advantages compared to other ...


Modeling Of A Continuously Variable Transmission And Clutching Of A Snowmobile, Camerin Michael Seigars May 2016

Modeling Of A Continuously Variable Transmission And Clutching Of A Snowmobile, Camerin Michael Seigars

Honors College

This thesis describes the conceptual operation of a continuously variable transmission (CVT) and develops a model of a CVT system. The purpose is to form a framework for understanding how CVTs work, what factors go into their design, why they are used on almost all modern snowmobiles, and how they can be tuned for better performance. By developing a model using rigid body analysis, computer modeling, and a list of structured equations, a CVT can be tuned more efficiently. The model is used to calculate values difficult or tedious to evaluate by hand with visual aide for clearer understanding of ...


Anthropometric Human Modeling On The Shape Manifold, Samuel Spicer Mate May 2016

Anthropometric Human Modeling On The Shape Manifold, Samuel Spicer Mate

Theses and Dissertations

The accuracy of modern digital human models has led to the development of human simulation engines capable of performing a complex analysis of the biometrics and kinematics / dynamics of a digital model. While the capabilities of these simulations have seen much progress in recent years, they are hindered by a fundamental limitation regarding the diversity of the models compatible with the simulation engine, which in turn results in a reduction in the scope of the applications available to the simulation. This is typically due to the necessary implementation of a musculoskeletal structure within the model, as well as the inherent ...


Modeling And Control Of Fuel Cell-Battery Hybrid Energy Sources, Nima Lotfi Jan 2016

Modeling And Control Of Fuel Cell-Battery Hybrid Energy Sources, Nima Lotfi

Doctoral Dissertations

"Environmental, political, and availability concerns regarding fossil fuels in recent decades have garnered substantial research and development in the area of alternative energy systems. Among various alternative energy systems, fuel cells and batteries have attracted significant attention both in academia and industry considering their superior performances and numerous advantages. In this dissertation, the modeling and control of these two electrochemical sources as the main constituents of fuel cell-battery hybrid energy sources are studied with ultimate goals of improving their performance, reducing their development and operational costs and consequently, easing their widespread commercialization. More specifically, Paper I provides a comprehensive background ...


On The Role Of Cell Distribution In Hydrolytically Degradable Hydrogels For Tissue Engineering, Gaspard De Roucy Jan 2016

On The Role Of Cell Distribution In Hydrolytically Degradable Hydrogels For Tissue Engineering, Gaspard De Roucy

Civil Engineering Graduate Theses & Dissertations

Degradable hydrogels have recently become prominent materials in the field of tissue engineering. They can be submitted to two degradation process: hydrolytic and enzymatic. For hydrolytically degradable systems, results seem to differ between samples. Yet the reasons for such a phenomenon have not been clearly understood. The objective of this thesis is to establish a multiscale model for such hydrogels. With the hypothesis that cross-linking density varies within a cell-seeded hydrogel, the present thesis aims to interpret experimental results to model and predict their behavior. First, a three-dimensional cell distribution is generated based on the analysis of experimental microscopy images ...


An Experimental Investigation Of The Effect Of Temperature And Space Velocity On The Performance Of A Cu-Zeolite Flow-Through Scr And A Scr Catalyst On A Dpf With And Without Pm Loading, Vaibhav Kadam Jan 2016

An Experimental Investigation Of The Effect Of Temperature And Space Velocity On The Performance Of A Cu-Zeolite Flow-Through Scr And A Scr Catalyst On A Dpf With And Without Pm Loading, Vaibhav Kadam

Dissertations, Master's Theses and Master's Reports

Abstract The heavy-duty diesel (HDD) engines use the diesel oxidation catalyst (DOC), catalyzed particulate filter (CPF) and urea injection based selective catalytic reduction (SCR) systems in sequential combination, to meet the US EPA 2010 PM and NOₓ emission standards. The SCR along with a NH₃ slip control catalyst (AMOX) offer NOₓ reduction >90 % with NH₃ slipHowever, there is a strong desire to further improve the NOₓ reduction performance of such systems, to meet the California Optional Low NOₓ Standard implemented since 2015. Integrating SCR functionality into a diesel particulate filter (DPF), by coating the SCR catalyst on the DPF, offers ...


Modeling The Feasibility Of Corn Stover Combustion As A Heat Source At Corn Ethanol Plants, Sulekha Tamvada Dec 2015

Modeling The Feasibility Of Corn Stover Combustion As A Heat Source At Corn Ethanol Plants, Sulekha Tamvada

Theses and Dissertations

Alternative energy sources are of prime interest for most of the nations across the world. Rising fuel prices and depleting petroleum reserves are of serious national and global concern. Bio-fuels if proved feasible for larger scale implementation could become the ideal breakthrough in easing the extensive dependence on fossil fuels and retaining the current engine technology of fossil fuels. Current methods of producing bio-fuels rely heavily on the consumption of non-renewable energy in the production process. Therefore, it is desirable to find renewable alternatives to these non-renewable energy sources.

Although bio-mass based fuels have been tested and proven to be ...


Computations And Detailing Of Pressure Vessels Having Unusual Requirements In Design, Anil Patnaik, Ashenafi Hegana, Tirumalai Srivatsan Aug 2015

Computations And Detailing Of Pressure Vessels Having Unusual Requirements In Design, Anil Patnaik, Ashenafi Hegana, Tirumalai Srivatsan

Anil Patnaik

The provisions of Australian Standard AS 1210-1989 for design and detailing of unfired pressure vessels can be applied to commonly encountered design situations where the shells have small openings. The technique of finite element analysis is a convenient and powerful tool for the purpose of computational stress analysis when the design requirements are such that either the openings are large, or where concentrated loads and/or thermal movements are present. This paper provides a summary of one such practical design of a pressure vessel. While the computational technique using finite element analysis simplifies the stress analysis of pressure vessels considerably ...


Systems Modeling And Economic Analysis Of Photovoltaic (Pv) Powered Water Pumping Brackish Water Desalination For Agriculture, Michael A. Jones May 2015

Systems Modeling And Economic Analysis Of Photovoltaic (Pv) Powered Water Pumping Brackish Water Desalination For Agriculture, Michael A. Jones

All Graduate Theses and Dissertations

Global growing demand for agricultural production has put increased pressure on freshwater resources in various global locations. Many areas have saline groundwater resources which have not been utilized for agriculture due to the economics associated with water pumping and desalination. Limited availability to electricity and high operational costs of diesel generators are major obstacles to utilization of these resources. Reduced costs associated with large-scale renewable energy have renewed interest in understanding the potential impacts of developing distributed photovoltaic (PV) powered water pumping and desalination systems for agriculture. In order to determine the economic feasibility of solar-powered water pumping and desalination ...


Modeling Of Environmentally Assisted Fatigue Crack Growth Behavior, Sree Phani Chandar Reddy May 2015

Modeling Of Environmentally Assisted Fatigue Crack Growth Behavior, Sree Phani Chandar Reddy

Dissertations

The formation of fatigue cracks and their propagation due to cyclic loading in metals have been a concern for more than hundred years. Since fatigue failure were first reported by the railroad industry in 1840s, tremendous progress has been achieved in understanding fatigue behavior of metals. But fatigue damage is still a concern due to its complex dependency on various environmental variable like humidity, temperature, time and corrosive environment. Although numerous theories and models have been proposed in the past, the effects of environment on fatigue crack growth (FCG) is not completely understood. This dissertation aims to shed light on ...


Creep And Shrinkage Behavior Of Fly Ash Based Geopolymer Concrete, Md Rashedul Islam Apr 2015

Creep And Shrinkage Behavior Of Fly Ash Based Geopolymer Concrete, Md Rashedul Islam

Doctoral Dissertations

The manuscript presented herein is based on the investigation of the short and long term properties of fly ash based geopolymer concrete (GPC) and their link to fly ash characteristics. Fly ash (FA) exhibits a significantly different particle morphology, which impacts the mechanical properties of the resulting GPC and typically contains impurities that fluctuate from one FA source to another. A key contribution of this research work is the capturing of the variability posed by the FA stockpile with a wide range of physical, chemical, and crystallographic characteristics as a source material to select the GPC mix design. In the ...


Molecular Modeling Of Epon 862-Detda / Carbon Composites, Cameron Hadden Jan 2015

Molecular Modeling Of Epon 862-Detda / Carbon Composites, Cameron Hadden

Dissertations, Master's Theses and Master's Reports - Open

The thermoset epoxy resin EPON 862, coupled with the DETDA hardening agent, are utilized as the polymer matrix component in many graphite (carbon fiber) composites. Because it is difficult to experimentally characterize the interfacial region, computational molecular modeling is a necessary tool for understanding the influence of the interfacial molecular structure on bulk-level material properties. The purpose of this research is to investigate the many possible variables that may influence the interfacial structure and the effect they will have on the mechanical behavior of the bulk level composite. Molecular models are established for EPON 862-DETDA polymer in the presence of ...