Mechanical Engineering Commons^™

Spinning Continuous Fibers For Nanotechnology, Yuris A. Dzenis

Department of Engineering Mechanics: Faculty Publications

Nanotubes of carbon and other materials are arguably the most fascinating materials playing an important role in nanotechnology today. Their unique mechanical, electronic, and other properties are expected to result in revolutionary new materials and devices. However, these nanomaterials, produced mostly by synthetic bottom-up methods, are discontinuous objects, and this leads to difficulties with their alignment, assembly, and processing into applications. Partly because of this, and despite considerable effort, a viable carbon nanotube–reinforced supernanocomposite is yet to be demonstrated. Advanced continuous fibers produced a revolution in the field of structural materials and composites in the last few decades as a …

The Development Of An Accelerated Testing Facility For The Study Of Deposits In Land-Based Gas Turbine Engines, Jared Wilfred Jensen

Theses and Dissertations

Turbine engine efficiency modeling depends on many parameters related to fluid dynamics and heat transfer. Many of these parameters change dynamically once the engine enters service and begins to experience surface degradation. This thesis presents a validation of the design and operation of an accelerated testing facility for the study of foreign deposit layers typical to the operation of land-based gas turbines. It also reports on the use of this facility in an effort to characterize the change in thermal resistance on the surface of turbine blades as deposits accumulate. The facility was designed to produce turbine deposits in a …

Experimental And Numerical Investigation Of Turbulent Flow Induced Pipe Vibration In Fully Developed Flow, Matthew T. Pittard, R. Daniel Maynes, Jonathan D. Blotter, Robert P. Evans

Faculty Publications

Flow-induced pipe vibration caused by fully developed pipe flow has been observed but not fully investigated when turbulent flow prevails. This article presents experimental results that indicate a strong correlation between the volume flow rate and a measure of the pipe vibration. In this work, the standard deviation of the frequency-averaged time-series signal, measured using an accelerometer attached to the pipe, is used as the measure of pipe vibration. A numerical, fluid-structure interaction (FSI) model used to investigate the relationship between pipe wall vibration and the physical characteristics of turbulent flow is also presented. This numerical FSI approach, unlike commercial …

Laser-Assisted Fabrication Of Nmr Resonators, William W. Brey, Susan D. Allen

Mechanical Engineering - Daytona Beach

A detection coil for use in nuclear resonance magnetic (NMR) spectroscopy and a method of manufacture thereof. At least two film layers of material are deposited on an outer surface of a cylindrical tube of dielectric material. The layers are patterned to form a solenoid on the tube. At least one of the deposited materials is a conductor.

Development Of A Multidisciplinary Engineering Foundation Spiral, Samuel Bogan Daniels, Bouzid Aliane, Jean Nocito-Gobel, Michael Collura

Engineering and Applied Science Education Faculty Publications

To operate effectively in today’s workforce engineers need to have a muti-disciplinary perspective along with substantial disciplinary depth. This broad perspective cannot be achieved by merely taking 2 or 3 engineering courses outside of the major, but rather will require a radical change in the way we educate engineers. The faculty of the School of Engineering and Applied Science at the University of New Haven have developed a new approach: the Multidisciplinary Engineering Foundation Spiral. This curricular model provides the needed mix of breadth and depth, along with the desired professional skills, by providing carefully crafted, well-coordinated curricular experiences in …

Project-Based Introduction To Engineering -- Course Assessment, Samuel Bogan Daniels, Michael Collura, Bouzid Aliane, Jean Nocito-Gobel

Engineering and Applied Science Education Faculty Publications

The School of Engineering and Applied Science at the University of New Haven has a newly developed project-based Introduction to Engineering course. This new course plays a central role in the new Multi-Disciplinary Engineering Foundation Spiral curriculum as the first semester course for all engineering freshmen. An assessment process was developed to determine the effectiveness of this project-based course, specifically with attention towards assessing attitudes, impact on retention, problem-solving and engineering foundation topics. This paper addresses the particular portion of the assessment process for the individual course projects and their contribution to the last two assessment categories.

Project-Based Introduction To Engineering - A University Core Course, Samuel Bogan Daniels, Bouzid Aliane, Jean Nocito-Gobel, Michael Collura

Engineering and Applied Science Education Faculty Publications

This paper describes a first year engineering course that is taken by both engineering and non-engineering students. The project-based Introduction to Engineering course, EAS107P, fulfills a university core curriculum elective. Although engineering students take the course during their first year, students from other majors typically elect to take the course later in their curriculum. The focus of EAS107P is to have students experience the engineering design and problem solving process in a multi-disciplinary, team-based setting. In addition to learning about design, students develop an interest in the engineering profession and build a foundation of skills for future work. An additional …

Project Planning & Development For Engineering Freshmen, Bouzid Aliane, Michael Collura, Samuel Bogan Daniels, Jean Nocito-Gobel

Engineering and Applied Science Education Faculty Publications

The nature and background of students seeking an engineering education has changed drastically in the last decade, as has the expectations of industrial employers. Many students lack the organizational skills needed for academic success. Similar organizational skills, although more advanced, are required for managing engineering projects. A new course was developed by the faculty at the School of Engineering and Applied Science at the University of New Haven. Through this course, a key component of the Multidisciplinary Engineering Foundation Spiral, seeks to promote higher retention rates, increase student motivation and begin a confidence-building transition to professional practice. Project management concepts …

Effects Of Friction Stir Processing On The Microstructure And Mechanical Properties Of Fusion Welded 304l Stainless Steel, Colin J. Sterling

Theses and Dissertations

Friction stir processing (FSP) has been utilized to locally process regions of arc weldments in 304L stainless steel to improve the microstructure and mechanical performance. The cast microstructure and coarse delta-ferrite has been replaced with a fine-grained wrought microstructure. Furthermore, twins were introduced throughout the friction stir processed region. Although sub-surface sigma and carbides were introduced during FSP, their presence is not expected to adversely affect the resulting mechanical or corrosion properties of friction stir processed 304L arc welds. The resulting mechanical properties of FS processed weldments were also an improvement over as-welded arc welds. FSP resulted in an increase …

Application Of Genetic Algorithm To The Shape Optimization Of A Constrained Double-Chamber Muffler With Extended Tubes, Long-Jyi Yeh, Ying-Chun Chang, Min-Chie Chiu

Journal of Marine Science and Technology–Taiwan

As the compact design of a muffler system within a constrained environment of a existing machine room becomes obligatory, it also becomes essential to maximize the acoustic performance of mufflers under space constraints. In this paper, the shape optimization of a double-chamber muffler with an extended tube is presented. The main characteristic of the solution methodology is the use of genetic algorithm (GA) as the optimizer. In the paper, the acoustic performance of sound transmission loss (STL) derived by transfer matrix is conjugated with the techniques of GA searching. A numerical case of noise elimination in full band noise is …

Re-Examination Of “Missing Strain” During Superplastic Deformation Of Aa7475, M. J. Tan, C. L. Chen, Namas Chandra

Department of Mechanical and Materials Engineering: Faculty Publications

“Missing strain,” a discrepancy between the total macroscopic strain and the strain contributed by grain boundary sliding (GBS) during superplastic deformation, appears to exist in previous investigations. In this work, the contri¬bution of GBS (ξ_GBS) and intragranular strain (ξ_IG) were simultaneously measured using scratch test conducted on AA7475 samples after deformation at 500 °C at initial strain rate of 10^-3 s^-1. The result shows that the missing strain results most probably from the neglect of the intragranular strain as well as the anisotropic GBS-induced underesti¬mation of ξ_GBS. The calculation of ξ …

Analysis Of Dynamic Characteristics For Wide Slider Bearings With An Exponential Film Profile, Jaw-Ren Lin, Chi-Ren Hung

Journal of Marine Science and Technology–Taiwan

Analysis of dynamic characteristics plays an important role in designing hydrodynamic bearings. Based upon the thin-film lubrication theory, the analysis of dynamic characteristics for a wide slider with exponential film profiles is presented when taking into account the bearing squeezing action. By applying a small perturbation technique to the dynamic Reynolds-type equation, both of the steadystate performance and the dynamic characteristics are then evaluated. Comparing with those of slider bearings with an inclined-plane film shape, higher values of the load-carrying capacity, stiffness coefficient and damping coefficient are predicted for the bearing with larger values of the inlet-outlet film ratio. These …

Jun 2004, Tractor Museum

Lester F. Larsen Tractor Museum: Planning and Development Documents

Vinod Gupta Gift Camp Creek Swap Meet UNL Signage to Museum

Effect Of Gender And Defensive Opponent On The Biomechanics Of Sidestep Cutting, Scott G. Mclean, Susanne W. Lipfert, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

Purpose: Anterior cruciate ligament (ACL) injuries often occur in women during cutting maneuvers to evade a defensive player. Gender differences in knee kinematics have been observed, but it is not known to what extent these are linked to abnormal neuromuscular control elsewhere in the kinetic chain. Responses to defense players, which may be gender-dependent, have not been included in previous studies. This study determined the effects of gender and defense player on entire lower extremity biomechanics during sidestepping.

Methods: Eight male and eight female subjects performed sidestep cuts with and without a static defensive opponent while 3D motion and ground …

Influence Of Friction Stir Welding On The Microstructural Evolution, Mechanical Properties And Superplastic Behavior Of Al-Cu-Li Alloy (Aa 2095), Moataz Attallah

Archived Theses and Dissertations

Friction Stir Welding (FSW) is a new solid state welding technique which is characterized by its ability to join the difficult-to-weld alloys, notably aluminum alloys. Microstructural studies revealed that FSW produces fine grain structure within the weld nugget due to the extensive plastic deformation and dynamic recrystallization (DRX) associated with it. Further studies hypothetically suggested that thermo-mechanical processing using friction stir can be used as a technique to create ultra-fine grain structure for superplastic forming (SPF). Yet, a more practical and economic suggestion indicated the suitability of combining FSW with SPF technologies in a way similar to the existing combination …

Agile Manufacturing System Scheduling Using Genetic Algorithms And Simulated Annealing, Sherif Masoud

Archived Theses and Dissertations

Agile manufacturing is concerned with thriving in prevailing market conditions by quickly introducing new or modified products. This research deals with the scheduling of an agile manufacturing system (AMS), which performs both machining and assembly, with the objective of minimizing the makespan. The AMS allows the production of high varieties of modular products in small batches and at low costs. This problem is difficult to solve optimally and was solved in literature by heuristic algorithms. In the current research, four novel, genetic algorithms and simulated annealing-based, heuristics – General Genetic Algorithm, General Simulated Annealing, Heuristic Assisted Genetic Algorithm, and Heuristic …

Analysis Of The Cup Drawing Process And Optimization Of The Blank Holder Force, Hossam Gharib

Archived Theses and Dissertations

The process of deep drawing of a cylindrical cup is analyzed and optimized for the minimum punch force. An analytical model is developed for the cup drawing process by determining the variation of stresses and strains over the deforming sheet at any stage of deformation until a full cup is formed. The model uses finite difference approach and numerical analysis to solve for equilibrium, continuity, and plasticity equations. Then, optimization of the blank holder force (BHF) is carried out using the developed analytical model. Optimization is carried out using genetic algorithms to determine the optimum linear BHF scheme that minimizes …

The Design Of Adjustable Spherical Mechanisms Using Plane-To-Sphere And Sphere-To-Plane Projections, Wen-Tzong Lee

Dissertations

The spherical mechanism is a particular type of spatial mechanism. Due to the orientation of its joint axes and the curvature of its links, the workspaces of spherical mechanisms (whether line segments, closed loops or area regions) are spherical in curvature. This characteristic of spherical mechanisms makes them quite effective and practical in motion path and function generation applications requiring spherical rigid body kinematics.

Although there are design methods available for spherical mechanisms, most of these methods do not consider the design of a single adjustable spherical mechanism. With an adjustable spherical mechanism, the user could for example, relocate the …

3-D Numerical Simulation Of Reactive Extrusion And Its Application To Polymerization Of Ε-Caprolactone In Co-Rotating Twin-Screw Extruders, Linjie Zhu

Dissertations

A 3-D numerical simulation model was proposed to predict the polymerization of ε-caprolactone in fully-filled conveying elements and kneading blocks of co-rotating twin-screw extruders, in which the kinetics equation for polymerization is coupled with continuity equation, momentum equation, and energy equation. With the 3-D model, parametric studies have been carried out to investigate the effects of screw configurations, screw diameter, operational conditions, values of heat from reaction, initiator concentration, and heat transfer conditions at barrel surface upon the polymerization progress. Two simulation models for the polymerization in the partially-filled channels were developed based on the conveying mechanisms of the reaction …

Modeling And Control Of Surface Micromachined Thermal Actuators, Robert K. Messenger

Theses and Dissertations

A model that accurately describes the transient and steady-state response of thermal microactuators is desirable to provide guidance for design and operation. However, modeling the full response of thermal actuators is challenging due to the temperature-dependent material properties and nonlinear deformations that must be included to obtain accurate results. To meet these challenges a three-dimensional multi-physics nonlinear finite-element model was developed using commercial code. The Thermomechanical Inplane Microactuator (TIM) was chosen as a candidate application to validate the model. TIMs were fabricated using the SUMMiT V™ process and their response was measured using a high-speed camera. The TIMs were modeled …

Optimizing Manufactured Housing Energy Use, Florida Solar Energy Center, Mark Mcginley

FSEC Energy Research Center®

In partnership with the Florida Solar Energy Center (FSEC), two manufactured homes were located on North Carolina A&T State University's campus in Greensboro, NC and used in a side-by-side energy consumption comparison. One of the homes was built to the basic HUD code standard and the other was constructed with features expected to produce a home that was 50% more energy efficient.

FSEC and NCATSU began monitoring energy performance in both homes. In addition, the performance of each unit was evaluated using a DOE2 based computer energy analysis program developed by FSEC. A comparison of the performance of the units …

Combining Systematic Layout Planning And Computer Simulation In The Design Of Manufacturing Facilities, Akintoye M. Akinyoade

All-Inclusive List of Electronic Theses and Dissertations

In this study, the systematic layout planning (SLP) and computer simulation were combined to improve the layout design of a manufacturing facility using a case study.

Dynamic Mechanical And Thermal Analysis Of Aligned Vapor Grown Carbon Nanofibers Reinforced Polyethylene, Jose Jaime Taha-Tijerina

Theses and Dissertations - UTB/UTPA

Dynamic-mechanical and thermal characterization of aligned vapor grown carbon-nanofibers (VGCNFs)-reinforced high-density polyethylene (HDPE) has been performed. VGCNFs with diameters ranging from 50–200nm were used. Nanofibers were purified to remove amorphous carbon and metal catalyst, resulting in deagglomeration, and creating an open network that allowed polymer infiltration during mixing. High-shear mixing was used to disperse and distribute the nanofibers uniformly within the matrix. Extensional flow at different draw ratios (λ) was used to obtain anisotropic nanoreinforced composite (NC) tapes. Dynamic Mechanical Analysis (DMA) showed a dual increase, in storage and loss modulus, with draw ratio. This behavior is attributed to the …

Cavitation Effects On The Stability Of A Submerged Journal Bearing, Jerzy T. Sawicki, T. V. V. L. N. Rao

Mechanical Engineering Faculty Publications

A computational procedure for the mechanism of shear between the liquid sublayer and air cavity in the cavitation zone of a submerged journal bearing is presented here. Using the mass conservation principle, Elrod's universal equation is modified to take into consideration the shear of the air cavity in the cavitation region. Results of steady state and transient response for the submerged journal bearing using the present approach are compared with the universal equation based on the striated flow in the cavitation region. At steady state, the angular extent of cavitation region predicted by the present approach is higher than that …

Nebraska Summary S466: Massey Ferguson 6480 Diesel 32-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Foot And Ankle Forces During An Automobile Collision: The Influence Of Muscles, Elizabeth C. Hardin, Anne Su, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

Muscles have a potentially important effect on lower extremity injuries during an automobile collision. Computational modeling can be a powerful tool to predict these effects and develop protective interventions. Our purpose was to determine how muscles influence peak foot and ankle forces during an automobile collision. A 2-D bilateral musculoskeletal model was constructed with seven segments. Six muscle groups were included in the right lower extremity, each represented by a Hill muscle model. Vehicle deceleration data were applied as input and the resulting movements were simulated. Three models were evaluated: no muscles (NM), minimal muscle activation at a brake pedal …

Design And Simulation Of An Induction Skull Melting System, Taide Tan

UNLV Theses, Dissertations, Professional Papers, and Capstones

Incorporating volatile actinides, mainly americium into a metallic fuel pin (MFP) has been a serious problem due to americium’s high vapor pressure. An Induction Skull Melting (ISM) system was identified by Argonne National Laboratory (ANL) as a potential furnace design to cast MFPs. Through the development of the ISM system, the nuclear waste feedstock can be melted and injected into the mold for fabricating MFPs in the advanced nuclear fuel cycles. The main phenomena in this system include: induction melting process, casting process and mass transfer process of americium. Issues related to ISM system design for casting MFPs are discussed …

Adaptive Optimal Control Design For Stable Vibration Attenuation Of Active Constrained Layer Damping Beam Structure, Tatyana G. Korotkova-Egan

Theses and Dissertations - UTB/UTPA

Vibration suppression using active constrained layer damping (ACLD) has proven to be an invaluable means for improving the performance of a wide variety of engineering systems. The ACLD creates the hybrid of active and passive damping, attaining favorably high damping characteristics, while at the same time, combines unattractive attributes of both treatments, such as stability sensitivity. Control efforts are needed to achieve an adequate performance of the structures treated with ACLD. The purpose of this research is to investigate theoretically and numerically the adaptive optimal controller of the constrained layer damped beam system, using the classical three-layered distributed-parameter model that …

Numerical Modeling Of Friction Stir Welding: A Comparison Of Alegra And Forge3, Alma H. Oliphant

Theses and Dissertations

The objective of this research was to evaluate the capabilities of ALEGRA, a Sandia National Labs hydrocode, and Forge3, a Transvalor S.A. product, to accurately model the Friction Stir Welding Process. ALEGRA and Forge3 are discussed in light of the inherent challenges of modeling Friction Stir Welding, and a rotational boundary condition is added to ALEGRA. Results are presented from Friction Stir Welding modeling outputs from both ALEGRA and Forge3. ALEGRA is shown to be incapable of modeling the Friction Stir Welding process, in large part due to its focus on shock propagation, which causes extremely small time steps. Forge3 …

Use Of Positron Annihilation Spectroscopy For Stress-Strain Measurements, Ajit K. Roy

Transmutation Sciences Materials (TRP)

The purpose of this collaborative research project involving the University of Nevada Las Vegas (UNLV) and Idaho State University (ISU) is to evaluate the feasibility of determining residual stresses of welded, bent (three-point-bend), and cold-worked engineering materials using a new nondestructive technique based on positron annihilation spectroscopy (PAS). The proposed technique is to use γ-rays from a small MeV electron linear accelerator (Linac) to generate positrons inside the test sample via 2 pair production. This method can be used for materials characterization and investigation of defects in thick samples that usually cannot be accomplished by conventional positron technique or other …