Mechanical Engineering Commons^™

Induced Damping And Its Relationship To Beneficial Energy Harvesting In Dielectric Elastomers With Application To Walking, Heather L. Lai

Wayne State University Dissertations

This dissertation presents a novel, interdisciplinary research which addresses the potential of applying soft polymeric materials to strategically harvest biomechanical energy in a beneficial manner for use as a viable, low power source for on-board electronics. Of particular interest are electroactive polymers (EAP), which unlike other types of electromechanical smart materials such as piezoelectric ceramics, which are often brittle, have low elastic modulus and can exhibit large strains without substantial stress generations. One type of EAP, the dielectric elastomer (DE), which utilizes electrostatic forces built up across the dielectric polymer to convert between electrical and mechanical energy, is employed in …

Simulations And Experiments Of Fuel Injection, Mixing And Combustion In Di Gasoline Engines, Yi Zheng

Wayne State University Dissertations

Direct Injection (DI) has been known for its improved performance and efficiency in gasoline spark-ignition engines. In order to take all the advantages of the GDI technology, it is important to investigate in detail the interactions of fuel spray and combustion system, such as air-fuel mixing, in-cylinder flow development, surface wetting, and turbulence intensity. The characterizations of the internal nozzle flow of DI injector are first studied using the multidimensional computational fluid dynamic (CFD) simulation. In the meanwhile the numerical and experimental studies are carried out to observe the external spray and wall impingements in an optical constant volume vessel. …

Characteristics Of Cold Start Of A Diesel Engine Using Jp8 And Ulsd Fuels, Madhushankar Palanisamy

Wayne State University Theses

This study involves the cold start testing of ULSD and JP8 fuels on the 6 cylinder 7.2 liter turbocharged diesel engine at various ambient temperatures as low as 0oF for JP8 fuel and 10oF for ULSD fuel. Cycle by cycle analysis of the cold start transient data, along with the effects of variation in ambient temperature on the engine cranking speed and in cylinder motoring pressure were analyzed and presented. It was found that the reduction in ambient temperature resulted in prolonged cranking periods along with the longer time taken to reach idling speed as well as increased combustion instability. …

Life-Cycle Cost Analysis Of Alternative Reinforcement Materials For Bridge Superstructures Considering Cost And Maintenance Uncertainties, Christopher D. Eamon, Elin A. Jensen, Nabil F. Grace, Xiuwei Shi

Civil and Environmental Engineering Faculty Research Publications

A life cycle cost analysis (LCCA) was conducted on prestressed concrete bridges using carbon fiber reinforced polymer (CFRP) bars and strands. Traditional reinforcement materials of uncoated steel with cathodic protection and epoxy-coated steel were also considered for comparison. A series of deterministic LCCAs were first conducted to identify a range of expected cost outcomes for different bridge spans and traffic volumes. Then, a probabilistic LCCA was conducted on selected structures that included activity timing and cost random variables. It was found that although more expensive initially, the use of CFRP reinforcement has the potential to achieve significant reductions in life …

Multi-Fuel Operation Of Modern Engines; On Board Fuel Identification, Florin Mocanu

Wayne State University Dissertations

Modern engines require enhancement of electronic controls to achieve better fuel economy, higher power density and satisfactory emissions levels while operating safely.

Military vehicles should be capable to run safely and efficiently on any fuel available in the field, therefore on-board fuel identification and adaptation of engine controls to the type of fuel becomes extremely important. In these conditions, the use of an inexpensive, nonintrusive sensor is highly desirable.

The development of a technique based on the measurement of the instantaneous crankshaft speed and engine dynamics could be a convenient solution.

Several such methods have been elaborated at the Center …

An Integrated Framework For Configurable Product Assortment Planning, Seyed Ali Taghavi Behbahani

Wayne State University Dissertations

A manufacturer's assortment is the set of products or product configurations that the company builds and offers to its customers. While the literature on assortment planning is growing in recent years, it is primarily aimed at non-durable retail and grocery products. In this study, we develop an integrated framework for strategic assortment planning of configurable products, with a focus on the highly complex automotive industry. The facts that automobiles are highly configurable (with the number of buildable configurations running into thousands, tens of thousands, and even millions) with relatively low sales volumes and the stock-out rates at individual dealerships (even …

Contact Pressure Distribution Of Osteochondral Defects Of The Knee: Effects Of Non-Vertical Walls, Scott Ensminger

Wayne State University Theses

Purpose: To examine the relationship between well-shouldered osteochondral defects and

defects of different geometries by studying their effects on rim stress concentration and

load redistribution in the human knee.

Methods: Ten fresh-frozen cadaveric knees were mounted at 30° of flexion in a materials

testing machine. Digital electronic pressure sensors were placed in the medial and lateral

compartments of the knee. Dynamic pressure readings were recorded throughout the

loading and holding phases as each knee was loaded to 700N and held for 5 seconds.

Artificial defects were created in each knee to simulate well-shouldered defects and

beveled-defects. Loading was repeated for …

Free Vibration Analyses Of Abs (Acrylonitrile-Butadiene-Styrene) Rectangular Plates With Completely Free Boundary Conditions, Mehmet Akif Dundar

Wayne State University Theses

Acrylonitrile-Butadiene-Styrene (ABS) represents a family of engineering thermoplastics with a wide field of performance characteristics. ABS materials have been receiving a great deal of attention because of their unique properties, such as outstanding formability, high tensile strength and stiffness, very high impact strength, excellent ductility, excellent high and low temperature performance, and resistant to many chemicals and plasticizers. Particularly, ABS exhibits really high impact strength; therefore, it is used in industry products which require high impact strength materials, such as military helmets and construction safety helmets. The vibration analyses of ABS rectangular plates are incredibly significant for design in military …

Intricate Dynamics And Hydrodynamic Frictional Losses Of The Piston-Ring Assembly In Internal Combustion Engines, Mohannad Hakeem

Wayne State University Dissertations

Frictional losses in internal combustion engines approximately account for 10% of the expended fuel energy. Moreover, forty percent of these losses are attributed to the reciprocating motion of the piston-assembly. Besides the adverse effect of friction on fuel economy, the intricate dynamics of the piston-assembly tend to significantly influence the thermal efficiency through blow-by, the engine durability through wear, and the engine noise through piston-slap. Moreover, 40 to 80% of the lubricant oil consumption has been attributed to the ring-pack dynamics.

In this dissertation, a reliable tool has been developed using MATLAB/SIMULINK and embedded C-S Functions that predicts the intricate …

Linear And Non-Linear Deformations Of A Wind Turbine Blade Considering Warping And All Aeroelastic Load Couplings, Fouad Mohammad Mohammad

Wayne State University Dissertations

The structural dynamics behavior of the blade of a horizontal axis wind turbine that reacts to the different components of the aerodynamic loading were studied by many researchers using different approaches and assumptions. In the present research, the author considered all the extensional, torsional and flexural loadings acting on the blade with their couplings, variable airfoil cross sections with warping effects, shear deflection, rotary inertia and with or without blade's pretwist for both the linear small deformation case and the nonlinear large deformation case. To the best knowledge of the author the simultaneous inclusion of all these factors has not …

Optical Investigation Of Ethanol And N-Heptane Dual-Fuel Partially Premixed Combution In S Reciprocating Engine, Radu Catalin Florea

Wayne State University Dissertations

The details of the dual-fuel combustion of n-heptane and ethanol were investigated in an optically accessible engine representative of light-duty applications. Experimental work involved the application of optical diagnostics such as high-speed imaging of combustion chemiluminescence and soot radiation, spectral measurements and laser induced fluorescence. At the same time, the experimental conditions have been replicated using numerical simulation of chemically reactive in-cylinder flow.

The numerical simulation results, which showed good agreement with the experimental data across several validation approaches, provided an improved understanding of the mechanism responsible for the control of the rate of combustion for dual-fuel operation. The comparison …

Investigation And Improvment Of Noise, Vibration And Harshness(Nvh) Properties Of Automotive Panels, Mohammad Al Zubi

Wayne State University Dissertations

ABSTRACT

INVESTIGATION AND IMPROVEMENT OF NOISE, VIBRATION AND HARSHNESS (NVH) PROPERTIES OF AUTOMOTIVE PANELS

by

MOHAMMAD AL-ZUBI

July 2012

Advisor: Dr. Emmanuel Ayorinde

Major: Mechanical Engineering

Degree: Doctor of Philosophy

The reduction of noise and vibration in and across several components and modules of the automotive, such as the panels, doors, engine covers, seats, and others, is of primary importance. The NVH performance may be a crucial factor in the purchase decisions of numerous buyers. This work investigates through experimental, analytical and computational methods, six groups of sample materials - fabric, foam, honeycomb, monolithic and sandwich, periodic cellular material structures …

Gapped Cantilever For The Enhancement Of Strain Sensitivity And Energy Efficiency, Qinglong Zheng

Wayne State University Dissertations

Cantilever structures have been widely used in a large variety of transducer applications. For cantilever based transducers, piezoresistive/piezoelectric mechanisms has always been a popular choice due to the advantages of being low cost, simple structure and portability. However, low sensitivity is recognized as a major disadvantage of these transducers compared with optical based measurement. In this research, a gapped cantilever structure is proposed to potentially increase the sensitivity by orders of magnitude. In order to guide the design, an advanced analytical model is developed, and the increased strain sensitivity is theoretically demonstrated. In addition, optimizations with this model interestingly reveal …

Numerical Simulation And Experimentation Of Pulsatile Flows In Axisymmetric Arterial Models, Tadesse Gebreegziabher

Wayne State University Dissertations

ABSTRACT

NUMERICAL SIMULATION AND EXPERIMENTATION OF PULSATILE FLOWS IN AXISYMMETRIC ARTERIAL MODELS

by

TADESSE GEBREEGZIABHER

December 2011

Co-advisors: 1. Dr. Emmanuel Ayorinde 2. Dr. Trilochan Singh

Major: Mechanical Engineering

Degree: Doctor of Philosophy

The primary motivation for this dissertation is the fluid flow and structural response to unsteady blood flow in the human body. The research work is a synergistic merging of numerical simulation and experimentation. For the experiments, an all-encompassing, highly flexible experimental apparatus was designed and fabricated to facilitate a wide range of operating conditions, the range of which was chosen to accommodate mammalian cardiovascular system for both …

Spray Characterization Of Flex-Fuel Gasoline Di Injectors And Spray Interaction With Charge Motion In A Variable Valve Actuation Engine, Atsushi Matsumoto

Wayne State University Dissertations

The objective of this study is to understand the characteristics of GDI sprays and behavior of in-cylinder charge motion in a GDI engine which is equipped with variable valve actuation. High speed spray visualization in a spray chamber was conducted for a study of spray development. By Schlieren visualization technique, the effect of different conditions including ambient conditions (temperature, pressure) and injection conditions (fuel type, fuel temperature, nozzle design) on spray formation was discussed in both qualitative and quantitative methods. High-speed visualization of the in-cylinder charge motion was carried out as well using an optical accessible engine. The testing was …

Throughput Analysis And Bottleneck Management Of Production Lines, Hatice Ucar

Wayne State University Dissertations

Companies are increasing their manufacturing excellence in order to stay competitive in the globalizing market. Plants are becoming more complex year by year due to increasing product classes, hardware complexity, etc... The design and operation of manufacturing systems is of greater importance today than it was in the past. Many studies have been carried out on the design and operation of manufacturing systems by academicians and practitioners over the years, however, there is still no agreement on how to best predict and improve the factory performance (Gershwin, 2000). The studies are based on either analytical approaches or simulation-based approaches. Success …

The Effect Of Biodiesel Blends On A Multi-Cylinder Engine And The Impact On Aftertreatment, Amy Peterson

Wayne State University Dissertations

Recently, topics including global warming, increased environmental awareness, recycling, and organically produced meat and vegetables have been prevalent in the media and research arenas. The rapidly increasing cost for fossil fuels and the pursuit of environmental conservation has brought about the interest in a renewable and clean burning fuel, specifically biodiesel. Biodiesel, or vegetable oil ester as it was originally referred to, has been improving and progressing since the early 1900's. Fortunately, significant advancement in the understanding of raw vegetable oil as a fuel as well as converting it to ethyl or methyl esters, now known as biodiesel, has been …

Analytical And Experimental Investigations Of Ships Impact Interaction With One-Sided Barrier, Ihab M. Grace

Wayne State University Dissertations

This study deals with impact interaction of ships with one-sided ice barrier during roll dynamics. An analytical model of ship roll motion interacting with ice is developed based on Zhuravlev and Ivanov non-smooth coordinate transformations. These transformations have the advantage of converting the vibro-impact oscillator into an oscillator without barriers such that the corresponding equation of motion does not contain any impact term. Such approaches, however, account for the energy loss at impact times in different ways. The present work, in particular, brings to the attention the fact that the impact dynamics may have qualitatively different response characteristics to different …

Reconstruction Resolution Of Coherent Point Sources With Helmholtz Equation Least Squares, Richard Edward Dziklinski

Wayne State University Dissertations

The dissertation investigates the reconstruction of coherent point sources using Helmholtz Equation Least Squares (HELS) method based on measurements in violation of Nearfield Acoustical Holography (NAH) resolution guidelines. In HELS, the Helmholtz equation is solved by matching a series of localized spherical expansion functions to the measured pressures in the field. Expansion coefficients are solved for by least squares and used to reconstruct pressures at the source surface. By approximating the pressure radiation with expansion functions, field and surface pressures can be synthesized, resulting in the possibility of higher spatial resolution than previous generation NAH methods such as Fourier Acoustics …

Finite Element Reconstruction Of Real World Aortic Injury In Near-Side Lateral Automotive Crashes With Conceptual Countermeasures, Aditya Neelakanta Belwadi

Wayne State University Dissertations

Traumatic rupture of the aorta (TRA) remains the second most common cause of death associated with motor vehicle crashes after brain injury. On an average, nearly 8,000 people die annually in the United States due to blunt injury to the aorta. It is observed that more than 80% of occupants who suffer an aortic injury die at the scene due to exsanguination into the chest. With the advent of more accurate and established human body finite element (FE) models, FE crash reconstruction methods may become a valuable tool when assessing crash scenarios and occupant injury mechanisms.

The current study is …

Opposing Effects Of Recirculated Gases During Cranking On Cold Start Of Diesel Engines, Rafik N. Rofail

Wayne State University Dissertations

ABSTRACT

OPPOSING EFFECTS OF RECIRCULATED GASES DURING CRANKING ON COLD START OF DIESEL ENGINES

by

RAFIK ROFAIL

August 2011

Advisor: Dr. Naeim Henein

Major: Mechanical Engineering

Degree: Doctor of Philosophy

Enhancing cold start of DI diesel engines is the motivation behind this study. A new control strategy is proposed to reduce the cranking period and the white smoke emissions. In the strategy, the gases leaving the cylinder during the cranking period are recycled back into the intake manifold using two different methods. In the first method the engine-out gases during cranking are recirculated into the intake manifold and their rate …

Ionization In Diesel Combustion: Mechanism, New Instrumentation And Engine Applications, Fadi Estefanous

Wayne State University Dissertations

Diesel engines are known for their superior fuel economy and high power density. However they emit undesirable high levels of nitrogen oxide (NOx) and black particulate smoke (Soot). To reduce these emissions, close loop engine control strategies are required. Therefore, there is a need for an in-cylinder combustion sensor. The ion current sensor has been used for combustion sensing in gasoline engines for which ionization mechanisms have been developed. This is not the case in diesel engines.

In this dissertation, a new mechanism for ionization in diesel engines has been developed and experimentally validated. Moreover, a three dimensional model has …

Design And Fabrication Of A Prototype Aluminum Nitride-Based Pressure Sensor With Finite Element Analysis And Validation, Xinyu Du

Wayne State University Dissertations

Since 1985 when the first robot PUMA 560 was employed to place a needle during a brain CT biopsy, surgical robots have become ubiquitous in clinical surgeries. Despite its advantages and success in surgeries, the interactions between the robot and the surgeons remain deficient, especially for the pressure sensing which plays an important role. Inspired by our previous work on bacterial sensing, in the current work I have designed, fabricated, analyzed, and evaluated an innovative prototype pressure sensor based on Aluminum Nitride (AlN) Surface Acoustic Wave (SAW) and Shear Horizontal (SH)-SAW. This AlN-based device has unique superiority over other SAW …

Locating And Extracting Acoustic And Neural Signals, Na Zhu

Wayne State University Dissertations

This dissertation presents innovate methodologies for locating, extracting, and separating multiple incoherent sound sources in three-dimensional (3D) space; and applications of the time reversal (TR) algorithm to pinpoint the hyper active neural activities inside the brain auditory structure that are correlated to the tinnitus pathology. Specifically, an acoustic modeling based method is developed for locating arbitrary and incoherent sound sources in 3D space in real time by using a minimal number of microphones, and the Point Source Separation (PSS) method is developed for extracting target signals from directly measured mixed signals. Combining these two approaches leads to a novel technology …

The Fourier Spectral Element Method For Vibration Analysis Of General Dynamic Structures, Xuefeng Zhang

Wayne State University Dissertations

The Fourier Spectral Element Method (FSEM) was proposed by Wen Li on the vibration of simple beams (Li, 1999), and was extended to the vibration of rectangular plates (Li, 2004). This dissertation proposes a revised formulation on the vibration of rectangular plates with general boundary conditions, and extends the FSEM on the vibration of general triangular plates with elastic boundary supports. 3-D coupling formulation among the plates and beams is further developed. A general dynamic structure is then analyzed by dividing the structure into coupled triangular plates, rectangular plates, and beams. The accuracy and fast convergence of FSEM method is …

Reliability Estimation Of Complex Numerical Problems Using Modified Conditional Expectation Method, Christopher D. Eamon, Bulakorn Charumas

Civil and Environmental Engineering Faculty Research Publications

A simulation-based structural reliability analysis method is presented. It is intended as an alternate approach to estimate reliability for problems for which most-probable point of failure methods fail and when computational resources are limited. The proposed method combines conditional expectation and estimating the PDF or CDF of a selected portion of the limit state. In the proposed approach, complex limit state functions are simplified to two random variable problems. The success of the simplification depends on the quality of the CDF estimate. Results indicate that the method may provide accurate and efficient solutions for some difficult reliability problems.

Skewed Bridge Behaviors: Experimental, Analytical, And Numerical Analysis, Bang-Jo Chun

Wayne State University Dissertations

In the US, nearly 33.5% of highway bridges are skewed. In the past, these skewed bridges have been analyzed as straight bridges. Nevertheless, there exists an extensive literature indicating the mechanical behavior of skewed bridges being quite different from their straight counterparts. In this thesis, to better understand the behavior of skewed bridges, experimental, numerical, and analytical researches have been conducted. The analytical method proposed here is the first of its kind in the skewed bridge research, and is expected to aid the bridge engineers with their design.

First, a three dimensional finite element analysis (FEA) model was developed and …

A Novel Image Processing Platform Development For Preprocessing Images With Two-Phase Microstructures Containing Isolated Particles, Yuxiu Zhang

Wayne State University Theses

A novel image processing platform is developed in this thesis for pre-processing the images of two-phase microstructures containing isolated particles based on Matlab®. The two phases in this work represent martensite particles and ferrite matrix in Dual Phase steels that are developed for lightweight automotive body structures. An automated image processing tool is useful for obtaining statistical microstructure characteristics, important for better understanding material's deformation and fracture behavior. However, a generalized commercial software can not automatically realize the microstructural features of special interest, and a user-specified pre-processing tool is needed.

This platform utilizes the Matlab® GUI technique, Matlab image processing …

Effect Of Alternative Fuels On Aftertreatment Device, Bunpreet Singh

Wayne State University Theses

EFFECT OF ALTERNATIVE FUELS ON THE AFTERTREATMENT DEVICE.

by

BUNPREET SINGH

Dec 2010

Advisor: Dr. Dinu Taraza

Major: Mechanical Engineering

Degree: Master of Science

There is no doubt that globally, alternative fuels have attained the center of attention in order to reduce the dependency on fossil fuels. A lot of research has been conducted on the alternative fuels in the automotive industry pertaining to the sustainability, engine performance and the emission characteristics.

The focus of this study is to investigate the effect of alternative fuels (JP8, Soy-based B20, and S8) on the aftertreatment device. Different fuel properties (both physical and …

The Fourier Spectrum Element Method For Vibration And Power Flow Analysis Of Complex Dynamic Systems, Hongan Xu

Wayne State University Dissertations

A general numerical method, the so-called Fourier-Space Element Method (FSEM), is proposed for the vibration and power flow analyses of complex built-up structures. In a FSEM model, a complex structure is considered as a number of interconnected basic structural elements such as beams and plates. The essence of this method is to invariably express each of displacement functions as an improved Fourier series which consists of a standard Fourier cosine series plus several supplementary series/functions used to ensure and improve the uniform convergence of the series representation. Thus, the series expansions of the displacement functions and their relevant derivatives are …