Mechanical Engineering Commons^™

Simulation And Control System Of A Railroad Track Power Harvesting Device, Kyle J. Phillips

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

With the vastness of existing railroad infrastructure, there exist numerous road crossings which are lacking warning light systems and/or crossing gates due to their remoteness from existing electrical infrastructure. Along with lacking warning light systems, these areas also tend to lack distributed sensor networks used for railroad track health monitoring applications. With the power consumption required by these systems being minimal, extending electrical infrastructure into these areas would not be an economical use of resources. This motivated the development of an energy harvesting solution for remote railroad deployment.

This thesis describes a computer simulation created to validate experimental on-track results …

Modeling, Finite Element Analysis, And Optimization Of Non-Pneumatic Tire (Npt) For The Minimization Of Rolling Resistance, Mallikarjun Veeramurthy

All Theses

Recently, the development of non-pneumatic tires (NPT) such as the Michelin Tweel is receiving increased attention due to potential advantages over pneumatic tires such as low mass, no run flat, good contact pressure distribution, and low rolling resistance (RR). This study focuses on the design of a NPT based on properties of vertical stiffness, contact pressure, and rolling energy loss. Using a finite element (FE) model, a parametric study is conducted to study the effect on vertical stiffness, contact pressure, and rolling resistance (RR) response considering three design variables: (1) thickness of the spokes, (2) the shear band thickness, and …

Modeling And Finite Element Alaysis Of Fluid Structure Interaction In A Wind Energy Harvester, Bargav Cheruku

All Theses

An energy harvesting system inspired by musicplaying harmonicas was developed for microwind power generation. The energy harvester uses flow-induced self-sustained oscillations of a piezoelectric beam embedded within a chamber to generate electric power. While the power generation capability of the energy harvester has been demonstrated previously, there is a lack of understanding behind the basic physics of the driving mechanism responsible for the self-sustained oscillations. In addition, the performance of the nonlinear multi-physics system with strong fluid and structure coupling depends on many physical and design parameters. A systematic study on the effects of these parameters is necessary for the …

Constrained Layer Damping Of Honeycomb Composite Structures, Rohit Telukunta

All Theses

Composite sandwich structures have replaced homogenous dense solids in many applications due to their advantages of high stiffness to weight ratio, and higher damping characteristics. Higher damping in engineering applications is desirable to reduce structural vibrations. The application of a viscoelastic layer between two thin face sheets gives rise to the concept of constrained layer damping which is an effective technique to achieve increased damping in engineering applications.
Honeycomb cellular structures are often used for the core in sandwich construction because of their low density and high stiffness properties. Regular honeycombs are defined by conventional hexagonal geometry, which gives rise …

A Priori Analysis Of Subgrid-Scale Heat Flux Vectors In High Pressure H2/O2 Mixing And Reacting Shear Layers, Ayse Korucu

All Theses

A Direct Numerical Simulation (DNS) database of supercritical, transitional H2/O2 mixing and reacting shear layers is analyzed in an a priori manner to obtain subgrid statistics relevant to Large Eddy Simulation (LES) engineering modeling. The DNS employs a real gas state equation, detailed chemistry, accurate property models, multicomponent, differential, and cross diffusion. The parallel simulations were conducted using eighth order central finite differencing in conjunction with a fourth order accurate Runge-Kutta time integration, on resolutions up to 135 million grid points, and used up to 2,016 processing cores. All simulations are for an ambient pressure of 100 atm and are …

Molecular Dynamics Study Of Particle Impact Induced Bond Breaking Of Single-Walled Carbon Nanotubes And Quality Factors Of Nanocomposite Structures, Puroorava Annapaneni

All Theses

Part A
Injection of particles to the side wall of single-walled carbon nanotubes (SWCNT) has been employed for doping and storage of particles on SWCNTs. In addition, particle bombardment can be used to cut and modify graphene structures. While the collision of hydrogen atoms with SWCNTs has been extensively studied, collision dynamic behavior of heavy particles with SWCNTs has not been well understood. To facilitate a better understanding of the particle-SWCNT collision process, in this work, we study the impact of five noble gas atoms (He, Ne, Ar, Kr, Xe) with SWCNTs and investigate particle impact induced CNT bond breaking …

Model-Based System Fault Diagnosis Utilizing Adaptive Threshold With Application To Automotive Electrical Systems, Ali Hashemi

All Theses

Recent advancement in the field of automotive industry is largely due to the addition of electrical and electronic equipment; some of the safety features in the vehicle and advanced driver assistance systems are examples of such equipment. Furthermore, safe operation of the vehicle is highly dependent on the electrical power generation and storage system (EPGS). Therefore, to ensure optimal operation of this system, a reliable diagnosis of the system is essential. However, as the complexity of the electrical systems has increased, the identification of a malfunction has become an increasingly difficult task to handle.
In the current work, a model-based …

Computational Analysis Of The Dynamic Forces In Drive Train Components Of An Offshore Wind Turbines, Artem Korobenko

All Theses

Wind has good potential for contributing to the national energy supply. Offshore sites and deep sea locations can be especially attractive as the wind turbine market grows. In such places larger wind resources are available with reduced turbulence intensity and wind shear. In addition, visual impact along with noise aspects are reduced. Offshore siting requires greater attention to structural stability and endurance. Forces on drive train components, such as the bearing system, are not well understood.
This work presents the development a model that calculates dynamical forces in drive train components of off-shore wind turbines. The model of a 5MW …

Understanding The Role Of Functions And Interactions In The Product Design, Raveesh Ramachandran

All Theses

Engineering designers often generate design concepts based on a functional understanding of the problem. Many engineering textbooks encourage designers to abstract the essential problem to a higher-level functional representation of the product and subsequently develop solutions to the functional needs. However, a functional perspective of design does not provide a complete view of what the product must do and how the product must interact with users and other parts. To address this, an alternative modeling approach has been developed to complement the traditional functional modeling approaches. Two such approaches include (1) activity modeling to capture the user actions from production …

Cfd Analysis Of The Under Hood Of A Car For Packaging Considerations, Sreekanth Reddy Gondipalle

All Theses

In recent years, there has been an increase in demand towards the improvement of car design for achieving better performance and increasing passenger comfort. Improving the design of individual components to meet the customer needs for improved vehicle performance alone is not enough. Interactions of these components with the surrounding components and their placement should also be investigated. Placement of these components in the under hood space forms a 3-Dimensional packaging problem. In the past, a multi objective optimization process was setup to determine the optimal placement of these components in the car under hood space. Three main objectives were …

Friction Stir Welding (Fsw) Process Modeling And Fsw Joint Design For Blast Survivable Structures, Anand Hariharan

All Theses

In order to satisfy the need for better ballistic performance against lethal threats, new grades of Titanium (e.g. Ti-6Al-4V) and Aluminum (e.g. AA5083) alloys are being employed in the design of blast survivable structures. These better performing alloys are not readily amenable to conventional welding process or result in inferior welds when joined using conventional welding process. On the other hand, Friction Stir Welding (FSW), a relatively new welding process, has been found to be successful in producing good quality welds in these alloys. FSW also offers better weld performance in comparison with the conventional welding process. But the methodology …

A Method For Evaluating Manufacturing Change In Engineering Design, Christopher Brooks

All Theses

Design changes are a frequent occurrence over the life of a product that may be initiated by an update to the product functionality, new customer needs, or generational improvements. The costs associated with these changes are undesirable, and are often times greatly inflated by additional, unanticipated changes that result from change propagating throughout the system. Propagation paths occur when an initiating change to a component necessitates subsequent changes to coupled components, as the change continues to propagate throughout the product architecture. The nature of this change propagation is challenging to characterize and accurately predict. To address this issue, a change …

Analytical Solutions Using High Order Composite Laminate Theory For Honeycomb Sandwich Plates With Viscoelastic Frequency Dependent Damping, Nan Shan

All Theses

Analytical methods allow parametric changes in geometric and material properties of a honeycomb sandwich plate for studies of stiffness, mass, and damping characteristics with low computational cost. However, studies based on analytical methods are still limited with frequency independent damping models. Specifically, previous analytical models have not consider the frequency dependent damping for viscoelastic honeycomb core sandwich composites, while some work has been done on studying the honeycomb sandwich plate using finite element method, which can be computationally expensive for multiple parameter studies. Therefore, in this work, the honeycomb sandwich plate is studied analytically based on the cellular material theory, …

Extracting Depth Information From Stereo Vision System, Using A Correlation And A Feature Based Methods, Mahmoud Abdelhamid

All Theses

This thesis presents a new method to extract depth information from stereo-vision acquisitions using a feature and a correlation based approaches. The main implementation of the proposed method is in the area of Autonomous Pick & Place, using a robotic manipulator. Current vision-guided robotics are still based on a priori training and teaching steps, and still suffer from long response time.
The study uses a stereo triangulation setup where two Charged Coupled Devices CCDs are arranged to acquire the scene from two different perspectives. The study discusses the details of two methods to calculate the depth; firstly a correlation matching …

Understanding The Role Of A Bio-Inspired Surface Modification For Delayed Icing, Clayton Schenk

Graduate Theses and Dissertations

Atmospheric icing event is problematic for outdoor structures because it can damage, slow, impede, and danger general routine. For a wind turbine blade, it can damage, disrupt movement, and cause potentially dangerous ice throw. Anti-icing based on a surface texture is advantageous due to the low cost of maintenance and there is no additional requirement of energy output for preventing the icing problem. This work is based on the biomimicry of the superhydrophobic nature of the lotus leaf, whereas the limited wettability supports the water to flow freely from the surface structure. The phenomenon is based on a morphology and …

Variability Of Strain And Strain Rate In The Human Tibial Diaphysis During Walking, Tyler Franklin Rooks

Boise State University Theses and Dissertations

With the prevalence of stress fractures in the military and athletes of all levels, research into the pathology of this injury has taken flight in recent years. One area of research has focused on the role bone strain, which is known to be a factor in bone remodeling, has on stress fracture development. It has been difficult to perform studies in this area of research due to the invasiveness of in vivo measurements of the bone strain. Recently, a methodology for approximating the bone strain using a computational model was proposed by Al Nazer et al. (Al Nazer et al., …

The Effect Of Layer Orientation On The Mechanical Properties And Microstructure Of A Polymer, V. Vega, J. Clements, T. Lam, A. Abad, B. Fritz, N. Ula, Omar S. Es-Said

Mechanical Engineering Faculty Works

Rapid Prototyping (RP) is a method used everywhere from the entertainment industry to healthcare. Layer orientation is an important aspect of the final product. The objective of this research was to evaluate the effect of layer orientation on the mechanical strength and toughness of a polymer. The polymer used was a combination of two materials, ZP 130 and ZB 58, fused together in the Z Corporation Spectrum Z510 Rapid Prototyping Machine. ZP 130 is a powder composed of vinyl polymer (2-20%), sulfate salt (0-5%), and plaster that contains < 1% crystalline silica (50-95%). ZB 58 is a liquid composed of glycerol (1-10%), preservative (sorbic acid salt) (0-2%), surfactant (< 1%), pigment (< 1%), and water (85-95%). After removal from the machine the samples were sealed with Z bond 101 which is Beta-methoxyethyl cyanoacrylate (60-100%). The layer orientations studied were the crack arrestor, crack divider, and short transverse with various combinations of the three, for a total of seven orientations. The mechanical strength was evaluated using tensile testing and three-point bend testing. The toughness was evaluated by Izod impact testing. Five samples for tensile testing and three-point bend testing as well as 15 samples for the Izod impact test for each of the seven orientations were made. The total number of samples was 175. The crack arrestor orientation was the strongest main orientation for the tensile and three-point bend test. Weibull analysis was done on the Izod impact testing due to high variation in the results for the crack arrestor and short transverse directions. It was found that the layer orientation and surface roughness played a significant role in the penetration of the Z bond 101 coating and in the overall strength of the samples.

Characterizing And Optimizing The Molten Salt Cleaning, Yangyang Long

Theses and Dissertations - UTB/UTPA

Molten salt cleaning is an important cleaning approach in remanufacturing which can remove a variety of contaminants from metal substrates with high efficiency. Facing the very limited research of this approach in literature, this thesis intends to characterize molten salt cleaning process and optimize its parameters when big parts with complicated shapes are cleaned. Based on the development of molten salt cleaning and studies on contaminations, two experiments are conducted. The first one investigates the influences of the hot salts on three metal substrates and shows the applicable of cleaning carbon steel and grey iron parts with molten salt. The …

The Effects Of Retrogression And Reaging On Aluminum Alloy 2195, N. Ward, A. Tran, A. Abad, E. W. Lee, M. Hahn, E. Fordan, Omar S. Es-Said

Mechanical Engineering Faculty Works

A retrogression and reaging (RRA) treatment was performed on 2195 Al-Li Alloy. The exposure times were from 5 to 60 min, and the temperatures were from 200 to 250 A degrees C. Samples that were exposed to a salt spray test had overall similar mechanical properties as compared to those that were not exposed. The percent elongation, however, was significantly deteriorated due to the salt spray exposure. The mechanical properties of the 2195 samples were compared to those of 2099 samples exposed to similar treatments in an earlier study.

Electrokinetic Transport And Manipulation Of Particles In Curved Microchannels, Junjie Zhu

All Dissertations

The investigation of electrokinetic particle transport in confined microchannels has practical significances in a variety of applications ranging from traditional gel electrophoresis to electrokinetic microfluidics-based lab-on-a-chip devices. To date, however, studies on particle electrokinetics have been limited to primarily theoretical or numerical analyses in straight microchannels of simple geometries. Very little work has been done on electrokinetic particle motions in real microchannels which usually consist of one or multiple turns. This thesis is dedicated to the fundamental and applied studies of electrokinetic transport and manipulation of particles in various curved microchannels using a combined experimental, theoretical, and numerical method.
First, …