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Articles 2671 - 2700 of 13128
Full-Text Articles in Entire DC Network
The Relationship Between Mechanism Geometry And The Centers Of Stiffness And Compliance, Shuguang Huang, Joseph M. Schimmels
The Relationship Between Mechanism Geometry And The Centers Of Stiffness And Compliance, Shuguang Huang, Joseph M. Schimmels
Mechanical Engineering Faculty Research and Publications
A significant amount of research has been directed toward developing a more intuitive appreciation of spatial elastic behavior. Results of these analyses have often been described in terms of the elastic behavior (stiffness or compliance) centers. This paper investigates the properties of centers of stiffness and compliance and provides a fresh view of elastic center locations, specifically, the locus of centers associated with a given mechanism’s topology and geometry. We show that the location of the center of stiffness (compliance) for a set of elastic components connected in parallel (in serial) can be described in terms similar to the …
Juggling A Devil-Stick: Hybrid Orbit Stabilization Using The Impulse Controlled Poincaré Map, Nilay Kant, Ranjan Mukherjee
Juggling A Devil-Stick: Hybrid Orbit Stabilization Using The Impulse Controlled Poincaré Map, Nilay Kant, Ranjan Mukherjee
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The control design for juggling a devil-stick between two symmetric configurations is proposed. Impulsive forces are applied to the devil-stick at the two configurations; and impulse of the force and its point of application are modeled as the control inputs. The dynamics of the devil-stick is described by a single return Poincaré map, and it is shown that the control objective of juggling can be achieved by stabilizing a hybrid orbit. The impulse controlled Poincaré map (ICPM) approach, recently proposed for stabilization of continuous-time orbits of underactuated systems, is extended to achieve asymptotic stabilization of the hybrid orbit. The applicability …
Passive Intermodulation Under Different Spring Contact Conditions, Shengxuan Xia, Emmanuel Olugbade, Yuchu He, Yansheng Wang, Hanfeng Wang, Krishna Rao, Marco Poort, Haicheng Zhou, Warren Lee, Nicholas Mcdonnell, Jonghyun Park, Chulsoon Hwang
Passive Intermodulation Under Different Spring Contact Conditions, Shengxuan Xia, Emmanuel Olugbade, Yuchu He, Yansheng Wang, Hanfeng Wang, Krishna Rao, Marco Poort, Haicheng Zhou, Warren Lee, Nicholas Mcdonnell, Jonghyun Park, Chulsoon Hwang
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Modularized designs have been widely used in today's consumer electronic devices and flexible RF springs are used for electrical connections between the modules. In the meantime, aluminum alloy material becomes a common chassis option. It is well known that the oxidized chassis surface introduces a certain level of nonlinearity when contacted by the springs, as known as passive intermodulation (PIM). PIM is one of the well-known root causes of the RF desensitization (desense). This paper is focused on investigating the relationship between PIM and contact conditions of the springs, especially contact area. The PIM level behavior is explained mathematically by …
Feature Learning For Optimal Control With B-Spline Representations, Vinay Kenny, Sixiong You, Chaoying Pei, Ran Dai
Feature Learning For Optimal Control With B-Spline Representations, Vinay Kenny, Sixiong You, Chaoying Pei, Ran Dai
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The paper develops a feature learning-based method to solve optimal control problems using B-splines to approximate the optimal solutions. The feature learning-based optimal control method can quickly generate near-optimal trajectories for general optimal control problems subject to system dynamics and constraints. The steps in the proposed method are as follows: Firstly, by representing the state and control variables with B-spline functions, the optimal control problem is converted into an approximate nonlinear programming (NLP) problem, where parameters of the B-splines are identified as features of the optimal solution. Secondly, for a specific problem with designated inputs, a dataset of the optimal …
Model Predictive Control Of Energy Systems For Heat And Power Applications, Chethan Ramakrishna Reddy
Model Predictive Control Of Energy Systems For Heat And Power Applications, Chethan Ramakrishna Reddy
Dissertations, Master's Theses and Master's Reports
Building and transportation sectors together account for two-thirds of the total energy consumption in the US. There is a need to make these energy systems (i.e., buildings and vehicles) more energy efficient. One way to make grid-connected buildings more energy efficient is to integrate the heating, ventilation and air conditioning (HVAC) system of the building with a micro-scale concentrated solar power (MicroCSP) sys- tem. Additionally, one way to make vehicles driven by internal combustion engine (ICE) more energy efficient is by integrating the ICE with a waste heat recovery (WHR) system. But, both the resulting energy systems need a smart …
On-Ice Detection, Classification, Localization And Tracking Of Anthropogenic Acoustic Sources With Machine Learning, Steven J. Whitaker
On-Ice Detection, Classification, Localization And Tracking Of Anthropogenic Acoustic Sources With Machine Learning, Steven J. Whitaker
Dissertations, Master's Theses and Master's Reports
Arctic acoustics have been of concern in recent years for the US navy. First-year ice is now the prevalent factor in ice coverage in the Arctic, which changes the previously understood acoustic properties. Due to the ice melting each year, anthropogenic sources in the Arctic region are more common: military exercises, shipping, and tourism. For the navy, it is of interest to detect, classify, localize, and track these sources to have situational awareness of these surroundings. Because the sources are on-water or on-ice, acoustic radiation propagates at a longer distance and so acoustics are the method by which the sources …
Project-Based Learning In Non-Traditional Settings In Engineering Education, Mary Foss
Project-Based Learning In Non-Traditional Settings In Engineering Education, Mary Foss
Electronic Theses and Dissertations
The purpose of this study is to examine the effectiveness of utilizing the principles of Project-based learning (PJBL) in nontraditional settings in engineering education. There is ample literature related to the usage of PJBL techniques in engineering education but there are also challenges with incorporating PJBL within the curriculum. It is the aim of this dissertation to build upon this understanding of the advantages and limitations of PJBL in engineering education and identify areas within the existing body of knowledge in which more research is needed. This dissertation divides this topic into 4 sub-topics. The first sub-topic explores how PJBL …
Top-Down & Bottom-Up Approaches To Robot Design, Dylan Michael Covell
Top-Down & Bottom-Up Approaches To Robot Design, Dylan Michael Covell
Graduate Theses, Dissertations, and Problem Reports (ETD)
This thesis presents a study of different engineering design methodologies and demonstrates their effectiveness and limitations in actual robot designs. Some of these methods were blended together with focus on providing an easily interpreted project design flow while implementing more bottom-up, or feedback, elements into the design methodology. Typically design methods are learned through experience, and design taught in academia aims to shape and formalize previous experience. Usually, inexperienced engineers are taught approaches resembling the Verein Deutscher Ingenieure (VDI) 2221 process. This method presented by the Association of German Engineers in 2006 is regarded as the general system design process. …
Development Of A Machine Learning Model To Characterize The Performance Of A Selective Catalytic Reduction On Filter After-Treatment System For A Heavy-Duty Diesel Engine, Samuel A. Okeleye
Development Of A Machine Learning Model To Characterize The Performance Of A Selective Catalytic Reduction On Filter After-Treatment System For A Heavy-Duty Diesel Engine, Samuel A. Okeleye
Graduate Theses, Dissertations, and Problem Reports (ETD)
Particulate matter (PM) and Oxides of Nitrogen (NOx) are the major pollutants in diesel engines, an attempt to control one leads to an increase in the other, a phenomenon known as PM-NOx trade-off in diesel engine emission control. Currently, these two pollutants are controlled by the Diesel Particulate Filter (DPF) and the Selective Catalytic Reduction (SCR) after-treatment system respectively, in addition to the Diesel Oxidation Catalyst (DOC) which helps to provide 1:1 split of NO/NO2 and helps with raising exhaust gas temperatures. Today, heavy-duty diesel engines feature a DPF, a primary SCR and a secondary SCR. Despite this complex …
Adjust-A-Ramp, Taylor Sharrits, Courtney Banks, Emily Beck, Jazmin Buenrostro
Adjust-A-Ramp, Taylor Sharrits, Courtney Banks, Emily Beck, Jazmin Buenrostro
Williams Honors College, Honors Research Projects
Adjust-A-Ramp is a portable ramp designed to ensure the safety of consumers and prevention of damage to cars, specifically towards low profile cars. A low-profile vehicle includes any vehicle that has a clearance off the ground of 6.5 inches or less. Advantages of low-profile vehicles include improved handling, better braking, increased fuel efficiency, increased stability, and an overall luxury aesthetic. The reduced tire size increases grip on smooth surfaces with better wheel response, creating a fast, more efficient ride. The simple tire tread patterns and the stiff sidewalls allow for lower rolling resistance which increases fuel economy. The Adjust-A-Ramp can …
Zip Shoes, Derek Ford, Garret Freund
Zip Shoes, Derek Ford, Garret Freund
Williams Honors College, Honors Research Projects
For our honors project we intend to create a new urban mobility solution. They are called Zip Shoes; they will be a pair of shoes with built in propulsion. We plan to use our cumulative engineering knowledge to modify an existing pair of shoes such that they can safely propel the user on wheels. We hope to achieve this by adding an electric drive train and necessary structural components onto the shoes. We are pursuing this project because we have seen the popularity of other electronically driven personal transportation devices. These include the hover board, electric skateboards, and electric scooters. …
Integrating Wave-Powered Batch Reverse Osmosis With Pressure Retarded Osmosis For Higher Efficiency Desalination Method, David M. Warsinger, Akshay Rao, Abhimanyu Das, Sultan Alnajdi, Ali Naderi, Antonio Esquivel, Alondra Ramos, Cole Heald, Vivek Singh, Ryan Soltis, Kaitlyn Kelsey, Adriana Hisham, Aaron Harp, Bryan Pamintuan, Paige Beck, Matthew Sheridan, John Pacholski, Carolina Bernal Botero
Integrating Wave-Powered Batch Reverse Osmosis With Pressure Retarded Osmosis For Higher Efficiency Desalination Method, David M. Warsinger, Akshay Rao, Abhimanyu Das, Sultan Alnajdi, Ali Naderi, Antonio Esquivel, Alondra Ramos, Cole Heald, Vivek Singh, Ryan Soltis, Kaitlyn Kelsey, Adriana Hisham, Aaron Harp, Bryan Pamintuan, Paige Beck, Matthew Sheridan, John Pacholski, Carolina Bernal Botero
School of Mechanical Engineering Faculty Publications
Overpopulation, intensive industrial water usage and climate change are some of the occurrences that are exacerbating global water scarcity. By 2050, the United Nations predicts that over 6 billion people will be affected by water scarcity. Over 70% of the earth's surface is covered by oceans yet its water remains unusable due to the high salinity of seawater. Reverse Osmosis (RO) is the most common method of desalinating water but is dependent on non-renewable generated electricity to meet its high energy requirements. The majority of the power supplied to desalination plants is generated using emission-heavy fuels. Given the UN’s goal …
Laser-Assisted Sound Source Localization Inside A Solid Enclosure, Antonio Figueroa Mombela
Laser-Assisted Sound Source Localization Inside A Solid Enclosure, Antonio Figueroa Mombela
Wayne State University Dissertations
Sound source localization is typically conducted in open space so that the line of sight is not blocked among individual sensors. This research presents a new technology that enables one to see acoustically through a solid Plexiglass enclosure to locate a sound source stationed inside at some arbitrarily selected locations. By using SODAR technology, non-invasive laser-assisted microphones, analog, and digital signal processing (band-pass filtering, fast Fourier transform algorithm, cross-correlations, and triangulations) satisfactory sound source localization results were obtained. In this project, the enclosure walls were flat; only the azimuth angle of a sound source could be determined. To obtain the …
Assessment Of Small-Scale Mechanical Damage On Safety Performance Of Lithium-Ion Batteries, Maher A. Almohammedali
Assessment Of Small-Scale Mechanical Damage On Safety Performance Of Lithium-Ion Batteries, Maher A. Almohammedali
Wayne State University Dissertations
Battery safety studies of Li-ion batteries (LIBs) related to mechanical abusive loadinginvolving contact compression of hard objects, bending and nail penetration usually show that LIBs can withstand some mechanical deformation prior to internal short circuit (ISC). Stress or strain-based criteria has been suggested to understand local conditions between the anode, cathode and the separator due such abusive mechanical loading. A strain-based criterion has also been developed at Wayne State and reported in open literature (Newaz et al.) Focus of such work has been to determine strain levels that may rupture the separator putting in contact the anode and cathode leading …
Tractor Test 2253: John Deere 9rx 590, Nebraska Tractor Test Lab
Tractor Test 2253: John Deere 9rx 590, Nebraska Tractor Test Lab
Nebraska Tractor Tests
ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …
Test 2261: John Deere 6140m, Nebraska Tractor Test Lab
Test 2261: John Deere 6140m, Nebraska Tractor Test Lab
Nebraska Tractor Tests
ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …
Tractor Test 2248: John Deere 9rt 470, Nebraska Tractor Test Lab
Tractor Test 2248: John Deere 9rt 470, Nebraska Tractor Test Lab
Nebraska Tractor Tests
ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …
Test 2255: John Deere 5100m, Nebraska Tractor Test Lab
Test 2255: John Deere 5100m, Nebraska Tractor Test Lab
Nebraska Tractor Tests
ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …
Test 2256: John Deere 5115m, Nebraska Tractor Test Lab
Test 2256: John Deere 5115m, Nebraska Tractor Test Lab
Nebraska Tractor Tests
ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …
Nebraska Tractor Summary: 1234 John Deere 6r 145, Nebraska Tractor Test Lab
Nebraska Tractor Summary: 1234 John Deere 6r 145, Nebraska Tractor Test Lab
Nebraska Tractor Tests
ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …
Nebraska Tractor Summary: 1238 John Deere 6r 195 Diesel Infinitely Variable Transmission, Nebraska Tractor Test Lab
Nebraska Tractor Summary: 1238 John Deere 6r 195 Diesel Infinitely Variable Transmission, Nebraska Tractor Test Lab
Nebraska Tractor Tests
ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …
Nebraska Summary : 1235 John Deere 6r 155 Diesel Infinitely Variable Transmission, Nebraska Tractor Test Lab
Nebraska Summary : 1235 John Deere 6r 155 Diesel Infinitely Variable Transmission, Nebraska Tractor Test Lab
Nebraska Tractor Tests
ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …
Computational Modeling Of Respiratory Airflow In Human Distal Airways Using Hybrid Lung Model, Adnan Islam
Computational Modeling Of Respiratory Airflow In Human Distal Airways Using Hybrid Lung Model, Adnan Islam
Electronic Theses and Dissertations, 2020-2023
A major challenge in the Computational Fluid Dynamics (CFD) modeling of the human respiratory system is the complex variation of geometric scale from the trachea to the peripheral airways. The current literature on image-based lung flow analysis is limited to a few (typically 5) generations beyond the trachea. Such studies, which are limited largely by computational intensity and computational cost, also have limited accuracy. In this study we propose a hybrid methodology that enables CFD analysis from the middle to the distal airways through to the alveolar level. A hybrid lung model is generated where the middle airways are reconstructed …
Design Of Composite Joints Using Machine Learning Approaches, Natalie Richards
Design Of Composite Joints Using Machine Learning Approaches, Natalie Richards
Williams Honors College, Honors Research Projects
Adhesively bonded joints have an advantage in joining dissimilar engineering materials due to their high structural efficiency and being lightweight. These joints are either between two opposite laminates or between a composite laminate and a metal structure. The aerospace and automotive industries have seen an increase in utilizing these adhesive joints in their engineering applications. Joint strength along with the failure mode (adhesive, delamination, etc.) is the most important parameter to evaluate when understanding the capability of the adhesive joint. In this paper, a regression and a classification machine learning (ML) model are utilized to predict the failure load and …
Molecular Dynamics Simulation Study Of A Polymer Droplet Transport Over An Array Of Spherical Nanoparticles, Anish Thomas
Molecular Dynamics Simulation Study Of A Polymer Droplet Transport Over An Array Of Spherical Nanoparticles, Anish Thomas
Browse all Theses and Dissertations
This study uses molecular dynamics simulations to evaluate the dynamic behavior of a partially wetting polymer droplet driven over a nanostructured interface. We consider the bead-spring model to represent a polymeric liquid that partially wets a rough surface composed of a periodic array of spherical particles. Results show that at sufficiently small values of external force, the droplet remains pinned at the particle's surface, whereas above the threshold its motion consists of alternating periods of pinning and rapid displacements between neighboring particles. The latter process involves large periodic variation of the advancing and receding contact angles due to the attachment …
A Digital Twin For Synchronized Multi-Laser Powder Bed Fusion (M-Lpbf) Additive Manufacturing, Shayna Petitjean
A Digital Twin For Synchronized Multi-Laser Powder Bed Fusion (M-Lpbf) Additive Manufacturing, Shayna Petitjean
Browse all Theses and Dissertations
One of the technological challenges in the widespread application of additive manufacturing is the formation of undesired material microstructure and defects. Specifically, in metal additive manufacturing, the microstructural formation of columnar grains in Ti-6Al-4V is common and results in anisotropic mechanical properties and a reduction in properties such as ductility and endurance limit. This work presents the application of hexagonal and circular arrays of synchronized lasers to alter the microstructure of Ti-6Al-4V in favor of equiaxed grains. An anisotropic heat transfer model obtains the temporal/spatial temperature distribution and constructs the solidification map for various process parameters, including laser power, laser …
Behavior Of 3d Printed Polymeric Triply Periodic Minimal Surface (Tpms) Cellular Structures Under Low Velocity Impact Loads, Jesse James Leiffer
Behavior Of 3d Printed Polymeric Triply Periodic Minimal Surface (Tpms) Cellular Structures Under Low Velocity Impact Loads, Jesse James Leiffer
Browse all Theses and Dissertations
Surface-based lattice structures such as triply periodic minimal surface (TPMS) lattices are lightweight structures that are widely being investigated for applications in automotive, aerospace, military, railway, and naval structures. Due to the recent advent of three-dimensional (3D) printing (3DP) technologies, architected cellular materials such as surface- or strut-based periodic lattice cell structures have emerged as a unique class of lightweight metamaterials. These materials possess enhanced strength to weight ratio, high stiffness, exceptional capabilities in reducing noise and vibration, insulating heat, and effective impact energy absorption. Understanding the impact behavior of such materials are important so that they can be reliably …
Spatial Transformation Of A Layer-To-Layer Control Model For Selective Laser Melting, Xin Wang, Robert G. Landers, Douglas A. Bristow
Spatial Transformation Of A Layer-To-Layer Control Model For Selective Laser Melting, Xin Wang, Robert G. Landers, Douglas A. Bristow
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Selective Laser Melting (SLM) is an Additive Manufacturing (AM) technique with challenges in its complexity of process parameters and lack of control schemes. Traditionally, people tried time-domain or frequency-domain control methods, but the complexity of the process goes beyond these methods. In this paper, a novel spatial transformation of SLM models is proposed, which transforms the time-domain process into a spatial domain model and, thus, allows for state-space layer-to-layer control methods. In a space domain, this also provides the convenience of modelling laser path changes. Finally, a layer-to-layer Iterative Learning Control (ILC) method is designed and demonstrates the methodology of …
Combustion Feature Characterization Using Computer Vision Diagnostics Within Rotating Detonation Combustors, Kristyn B. Johnson May
Combustion Feature Characterization Using Computer Vision Diagnostics Within Rotating Detonation Combustors, Kristyn B. Johnson May
Graduate Theses, Dissertations, and Problem Reports (ETD)
In recent years, the possibilities of higher thermodynamic efficiency and power output have led to increasing interest in the field of pressure gain combustion (PGC). Currently, a majority of PGC research is concerned with rotating detonation engines (RDEs), devices which may theoretically achieve pressure gain across the combustor. Within the RDE, detonation waves propagate continuously around a cylindrical annulus, consuming fresh fuel mixtures supplied from the base of the RDE annulus. Through constant-volume heat addition, pressure gain combustion devices theoretically achieve lower entropy generation compared to Brayton cycle combustors. RDEs are being studied for future implementation in gas turbines, where …
Computational Analysis Of The Stability Limits Of Premixed Methane-Air Combustion In Micro-Channels, Almoutazbellah Adnan Kutkut
Computational Analysis Of The Stability Limits Of Premixed Methane-Air Combustion In Micro-Channels, Almoutazbellah Adnan Kutkut
Graduate Theses, Dissertations, and Problem Reports (ETD)
Technological progress in the last decades facilitated the development of integrated microsystem devices, including electrical and mechanical components for micro-electro-mechanical systems (MEMS). Such systems necessitate an external power supply, but typical batteries yet have some unavoidable limitations. To address this problem, numerous studies have been conducted to develop alternatives powered by micro combustion – in order to effectively utilize the high-density energy of hydrocarbon fuels. Such a global need has resulted in much more attention devoted to the combustion-based micro-power generation systems. However, to better understand the typical combustion characteristics in such microscale systems, design and performance restrictions need to …