Mechanical Engineering Commons^™

Prediction Of Airfoil Stall In Icing Conditions Using Wing Surface Pressures, Erik Pederson

Masters Theses

This thesis presents work on a Normalized Lift Coefficient instrumentation system that predicts airfoil stall in icing conditions. The system uses four surface pressures, measured aft of the ice formation, from which the aircraft's normalized lift coefficient is determined. The pressure port locations were selected such that the calibration algorithm remains nearly constant as the leading edge ice shape and thickness change. Data collected in the Western Michigan University Wind Tunnel is presented for three ice formations varying in both shape and thickness. The ice and no ice conditions were compared and a set of four ports was found that …

Small Below-Endurance-Limit Cycle Damage Contributions In Variable Sequence Loading For 2024-T351 Aluminum Alloy, Christopher M. Ngiau

Masters Theses

It is a common practice in industry today to totally discard the presence of small below-endurance/fatigue limit cycles while calculating damage accumulation using the Palmgren-Miner rule. However, it was experimentally found in a number of studies that small cycles with stress amplitudes below the fatigue/endurance limit do in fact contribute significantly to the damage accumulation in all types of materials. There was a need to investigate cases where small cycles would only be present for a certain percentage of the material's life. An experimental study was done on 2024- T351 aluminum alloy. Loading was done in low and high cyclic …

Active Local Volume Displacement Cancellation Of A Vibrating Baffled Beam, Marcellin Zahui

Dissertations

An active noise control apparatus is developed. The device reduces the sound radiated from a vibrating clamped beam. The attenuation of the sound field is obtained through minimization of local volume displacements of the vibrating beam. Two single-input/single-output cancellation devices are used. Each device employs a motion sensor and an acoustic actuator. The actuator is a loudspeaker equipped with a pressure sensor to detect its volume displacement. The motion sensor signal is related to the local volume displacement of the structure which is then reduced by a loudspeaker driven with an equal but opposing volume displacement. The volume displacement sensors …

Development Of Mechanical Properties Micromapping For Composite Polymer Systems, Zheng Huang

Masters Theses

By adoption of classic indentation models (Hertzian, modified Hertzian, Sneddon, JKR), the elastic properties of polymeric material can be measured by AFM. Heterogeneous thin films were fabricated from polymer blends with a wide range of Young's moduli and thermal transition temperature to test the developed procedure. Results show that the micromapping of elastic properties can be obtained concurrently for glassy and rubber phases as well as across the interface with a lateral resolution better than 100 nm. Application of the elasticity micromapping on heterogeneous polymeric materials reveals thermal transition temperature that coincides very well with bulk values. Depth profile also …

Experimental Investigation Of Water Spray Cooling Characteristics Of A Solid Heated Surface, Rainer F. Ponzel

Masters Theses

Water spray cooling characteristics of a solid heated surface were investigated to better understand the physical phenomenon of nucleate boiling heat transfer for full cone sprays. An experimental test loop was developed to conduct the spray cooling experiments. A uniform heat flux condition was assumed, and the liquid flow rate and nozzle orifice diameter were selected as the main variables. Two water temperatures were chosen to perform the study. Saturated water spray was utilized to measure the wall superheat temperature. Subcooled water spray was applied to investigate the effect of water spray in the single-phase regime.

Experiments conducted using the …

Flow Due To A Moving Pressure Distribution Over Free-Surface With Finite-Depth Bottom, Noriaki Okita

Masters Theses

Two-dimensional, steady-state and time-dependent analysis of wave making phenomenon due to a moving pressure distribution in sub-critical Froude number was performed. The domain is consisted of undisturbed free-surface at y=0, flat bottom at y=-h, and it is unbounded in horizontal direction. The pressure distribution was treated as an ideal model of an air-cushioned-vehicle (ACV). Ideal flow theory and linearized boundary conditions were used. Numerical integration algorithm was developed to evaluate the analytical solution. The surface elevation, bottom pressure profiles, and wave resistance were analyzed as functions of speed and depth.

The steady-state wave resistance calculated from the surface elevation profile …

Design And Development Of A User Interface Between Mapics/Db And Factor 5.2, Raghu Pothuri

Masters Theses

An interface program was designed to transfer production data from MAPICS/DB, a MRP II software, to FACTOR 5.2, a Finite Capacity Scheduling software. Since FACTOR 5.2 is designed to be used in a stand-alone mode with its own independent data base, this interface program extracts data from the MRP II System and converts it to formats specified by the Scheduling System. To create a computer model of the manufacturing process, information about manufacturing orders, routings, and production facilities was obtained from MAPICS/DB files. Certain information needed by FACTOR 5.2, which is not available in MAPICS/DB, was supplemented by the program …

Fuzzy Based Forebody Vortex Flow Controller For The X-29a Aircraft, Jin Suzuki

Masters Theses

This paper demonstrates the development and performance of A Fuzzy Logic based regulator for an aircraft which is equipped with pneumatic forebody Vortex Flow Controller at high angle-of-attack flight condition. The VFC provides the pilot additional control power at flight conditions where conventional effectors such as rudder and differential flaps lose effectiveness.

Fuzzy Logic Control (FLC) is applied to a mixed bang-bang and conventional type control system. This unique configuration ensures robustness of the system and simplifies the controller design. Performance of the FLC based regulator shows a 10.3% reduction in cost function compared to the system controlled by a …

Study Of Periodic Gust Loads On Airfoils, Tatsuya Nakajima

Masters Theses

The wings on aircraft can experience unsteady loads due to atmospheric disturbances; e.g., wind, the wakes of other aircraft, structural vibrations, or some combination of these sources. In some cases flow unsteadiness can be beneficial by augmenting the lift and reducing the drag; under different circumstances temporal variations in the flow can induce stall or cause structural failure.

In this study, the response of isolated (and tandem) NACA 0012 airfoil(s) to time-periodic unsteadiness have been investigated. The sources of unsteadiness include a time-varying free stream flow angle, a time varying free stream velocity magnitude, and an oscillating airfoil.

The predicted …

A Study Of Kanban Based Production System In Cellular Manufacturing Environment, Sanjay Bhargava

Masters Theses

The study of effects of production data variabilities on Kanban based cellular manufacturing system is vital before its design and implementation because it would give better understanding of their uncertain behavior.

In this research, a detailed analysis of a Kanban system, with subcell scenario, under dynamic operating conditions is performed. The Control variables considered were number of Kanbans, processing time variability, demand variability and machine breakdown. The performance parameters considered were profit, production lead time, machine utilization and material processing lead time.

Approximately 200 simulation runs were made with 3 replications each by varying one control variable at a time. …

An Investigation Of Turbulent Taylor-Couette Flow Using Laser Doppler Velocimetry In A Refractive Index Matched Facility, Joseph C. Parker

Masters Theses

Turbulent Taylor-Couette flow between an annulus formed by two concentric cylinders with dead end walls is comprised of complex patterns of vortices. An experimental apparatus was designed to provide refractive index matching between the annulus and working fluid. Optical access was maintained through three sides of the annulus and one end wall. An aqueous solution of sodium iodide was formulated to match the refractive index of the Plexiglas annulus. Laser Doppler Velocimetry was used to measure the three components of velocity and turbulence intensity throughout a planar section in the annulus. The annulus dimensions were: ƞ= 0.672, d = 15.08 …

The Effect Of Rotor Wake/Exit Guide Vane Interaction On The Total Pressure Losses In An Airfoil Cascade, Aaron Mosebach

Masters Theses

Computational simulations have been performed to study the effects of unsteady rotor wakes on the total pressure losses and the boundary layer characteristics in a compressor cascade. In the numerical simulations, transitional and turbulent flow conditions were modeled at design and off-design inlet flow angles, and for varying rotor wake widths and wake velocity deficits.

First, simulations were performed in the absence of rotor wakes at the inlet of the EGV (Exit Guide Vane) cascade. Second, simulations were performed for different wake width and wake velocity deficit values at the inlet of the EGV cascade. The majority of the numerical …

Dynamic Pulse Buckling Of Columns With Viscous Damping, Murli Kadandale

Masters Theses

This is a study of dynamic pulse buckling of columns with viscous damping. The differential equations of motion were obtained using the Bemoulli-Navier hypothesis. The effects of axial and rotary inertia were included in the analysis. The Voigt-Kelvin model for a viscoelastic material is used. The Finite Difference Method was employed to solve the differential equations of motion. First columns without geometrical imperfections were studied, and a correlation between the damping modulus and the more familiar damping ratio was obtained. Then beams with initial geometrical imperfection were studied. A suitable dynamic buckling criterion was defined. It was observed that viscous …

A Comparative Study Of The Stress Concentration Factors Arising Between Two Equal, Nearly Intersecting, Perpendicular, Pressurized Holes In An Infinite Solid With Those Arising Due To An Infinite Series Of Such Holes, Paul J. Drogowski

Masters Theses

Finite element analysis is used to determine the stress concentration factors arising from two equal, perpendicular, nearly intersecting, pressurized holes in an infinite solid while varying the distance and pressure ratios between the holes. The results are compared and contrasted with those previously obtained for an infinite series of such holes. A ratio of the distance between the holes to the diameter of the holes at which the holes can be considered to be single holes in an infinite solid is determined. A study is performed to determine a correlation between the location of the region of maximum stress and …

The Effects Of Non-Uniform Blade Geometries On Cascade And Turbine Stage Performance, Hiroyuki Maeda

Masters Theses

It is known that in-service turbomachinery blades do not have uniform shapes. There are small differences due to blade erosion, manufacturing tolerances, or faulty installation. These differences can be in the size, shape, or relative angles of the blade. In an effort to predict losses resulting from changes in blade thickness and/or blade angles, a two-part investigation has been conducted. A two-dimensional unsteady Navier-Stokes flow analysis has been used to perform numerical experiments.

First, simulations were performed for an isolated cascade. One of the two stators was scaled and/or rotated. Results of the numerical simulations show that increasing the blade …

An Investigation And Improvement Of Electrorheological (Er) Fluid Technology, Adil F. Dalal

Masters Theses

The purpose of this research was to investigate and overcome the limitations of Electrorheological (ER) fluids and to introduce this advanced technology at WMU. Electrorheological (ER) Fluids are a special class of fluids, which exhibit a reversible, infinitely variable phase transition from a liquid to a solid/semi-plastic state, in the presence of an electric field.

ER fluids can provide a unique solution to the problems of vibration isolation of systems. The applications are currently limited due to the high voltage requirements, electric power related heating and limited research into wear/abrasive characteristics of ER fluids.

A specially designed and constructed "electro-viscosimeter" …

Design Of A Miniature Hydraulic Power Unit, Ryan D. Bruneau

Honors Theses

The need for a newly designed miniature hydraulic power unit has received the attention of Parker-Hannifin Hydraulic Pump/Motor Division. The current power unit is no longer marketable due to the associated costs and its relative size. As a result, a miniature hydraulic power unit has been designed, the culmination to the engineering curriculum at Western Michigan University. In order to increase the overall marketability and to reduce production costs, a transparent plastic reservoir has been incorporated into the design. An appropriate polymer has been chosen to meet the design requirements and finite element analysis has been used to verify the …

An Empirical Study Of Just-In-Time And Total Quality Management Principles Implementation In Manufacturing Firms In The U.S., Loknath Sriparavastu

Masters Theses

Literature in vogue points out that, in the last decade, American manufacturing companies came a long way in their renewed emphasis on the quality process. Justin- Time (JIT) and Total Quality Management (TQM) are the two magical phrases that are being frequently used in almost all the articles published on quality and productivity. Nevertheless, the literature does not provide any satisfactory explanation as to how JIT and TQM principles are implemented in the manufacturing industries.

This research, through a nationwide empirical survey, analyzed the effects of JIT and TQM strategies implementation. Survey results showed that implementing both JIT and TQM …

Recent Advances In Engineering Design: Theory And Practice, Andrew J. Moskalik

Masters Theses

In the last few years, industry and academia have focused greater attention on the area o f engineering design. Manufacturers have implemented new design methods such as concurrent engineering and design for manufacture, and academia has increased research in design-related issues. This paper will attempt to summarize the recent advances, both scholarly and industrial, relating to the field of design. I will examine new methodologies and supporting tools for the design process, both in use and under research. This paper will cover concurrent engineering, design for manufacture, quality methods, design theory research, computer-aided design, expert systems, analysis programs, manufacturing, and …

Design Of A Vibration Excitation Device, Brian Wallace, Brandon Dawe

Honors Theses

A vibration excitation source has been designed for use in beam and plate vibration laboratory demonstrations. This source is capable of providing single frequency excitations below 160 cycles per second (Hz). Since it will be used in a variety of experiments by students, ease of use and quick setup time have been major considerations of design. Performance of this source has been evaluated and will be presented along with one example application.

Internal Acoustic Excitation Of An Airfoil Surface For Drag Reduction, Wendy L. Holforty

Masters Theses

This research investigated the effects of internal acoustic excitation on the boundary layer and surface of an airfoil. A NACA 16- 018 symmetric airfoil was tested in the Western Michigan University wind tunnel. The shedding vortex frequency of the airfoil was determined using hot-film anemometry. Using stroboscopic and holographic interferometry, the natural frequencies of the airfoil surface were determined. The airfoil surface was tuned such that the frequency of the shedding vortex is a resonant frequency and two internally mounted acoustic drivers were used to excite the surface of the airfoil at the shedding vortex frequency. The effects on pressure …

Primary Coolant Flow Characteristics As It Exits The Palisades Reactor, Gregory Alan Baustian

Masters Theses

During fuel cycles 9 and 10 at the Palisades Nuclear Power Plant, new phenomena have been observed using the resistance temperature devices installed in the reactor coolant piping. Oscillations in the temperature readings have been observed leading to the assumptions that there is temperature stratification of the coolant in the reactor hot-legs and that the coolant rotates as it leaves the reactor. In addition, oscillations in the bulk coolant flow within the two hot legs have been postulated. This report outlines work performed using computational fluid dynamics modelling which predict the observed and assumed flow characteristics of the Palisades reactor …

An Empirical Investigation Of Quality And Productivity Management Practices In Manufacturing Firms, Kiran Vuppalapati

Masters Theses

A growing number of firms are implementing the concept of Just In Time (JlT) manufacturing and Total Quality Management (TQM). This research examines the impact of these management philosophies in manufacturing firms.

This research identifies a set of critical organizational variables necessary for a successful . implementation and the organizational problems faced during their implementation. The major object is to test the performance of firms implementing both JlT and TQM against firms implementing none of these philosophies. Results show that JIT-TQM firms are more customer focused and have better employee relations than traditional firms. This study also compares the performance …

An Experimental Study Into The Role Of Routing Flexibility In The Justification Of Advanced Manufacturing Systems, Sanjay Pathak

Masters Theses

Increased competition in manufacturing has focused attention on advanced technologies. These costly technologies lead to difficulty in purchase justification using traditional methods. New methods quantify attributes relating to the flexibility of advanced systems. One such attribute is routing flexibility.

This thesis presents results of experiments into evaluation of routing flexibility. The performance of conventional dedicated machinery when compared with that of machines having routing flexibility indicates an advantage of flexible machinery. The thesis indicates a procedure for evaluation of different flexibilities and their comparison with conventional machinery in reality.

An empirical formula is developed that helps in quantifying routing flexibility …

Analysis Of Sandwich Plates Subjected To Blast Loading, Vijay Prasad Bulla

Masters Theses

A dynamic analysis is presented for the bending response of square sandwich plates with isotropic core and facings under blast type pressure. The maximum central deflections of simply supported plates under static and dynamic loadings are compared for various thicknesses and elastic moduli. The deviation of the thick sandwich plate results from the pure-bending theory results is presented for various core properties. Small deflection dynamic iso-response plots are shown for different core rigidities. To study the limits of small deformation linearity for various sandwich plates, non-linear results for deformations under high pressure loads are compared with the linear results. The …

Rolling Friction Research Instrument, John P. Ward

Masters Theses

An instrument has been analyzed, designed and constructed that will accurately measure the rolling resistance of metallic spheres an plane surfaces subjected to normal loading which will produce contact stresses approaching material yield.

Nonlinear Dynamic Finite Element Simulation Of Hydroelastic Mounts For Light Weight Vehicles, Talla Jayapal Reddy

Masters Theses

Modern light weight vehicles generate large noise levels, that may need bulky classical rubber mounts to suppress. Hydroelastic mounts can significantly reduce the vibration level of current production automobiles without weight penalty. However, the highly nonlinear behavior of hydroelastic mounts has not been established yet and its use is, therefore, limited to trial and error design methods.

This study discusses the implementation of nonlinear finite element simulation of hydroelastic mounts using the ANSYS finite element code. Fluid elements are limited to linear analysis and therefore are incompatible with the nonlinear hyperelastic elements. A method is proposed to simulate the fluid …

Wobbling Gear Drivetrain For Cordless Screwdriver, David K. Kedrowski, Scott P. Slimak

Honors Theses

Manufacturers of cordless screwdrivers use two planetary gear trains in series to reduce speed and multiply torque from a small electric motor. Alternately, a nutating gear drivetrain has the potential to create comparable speed reductions and torque multiplications. To apply nutating gear theory to a cordless screwdriver drivetrain, a study of spur gears, planetary gear reducers, bevel gears, and the theory of nutation was undertaken. Finally, a nutating design was proposed. The advantages of a nutating gear drivetrain over a conventional planetary gear train include: a decreased number of drivetrain parts, an ability to use lower-strength gear materials, a higher …

Silicon Carbide/Electroless Nickel Composite Plating For Aluminum Substrates, Ben Charbit

Masters Theses

The effectiveness of producing a composite coating by suspending micron-sized particles in an electroless nickel bath while plating a 2024T4 aluminum alloy part was studied. The variation in the count of particles trapped in the nickel coating due to changes in the particle size, concentration of the particles in the bath, and the substrate surface texture was also studied. Particle sizes of 1 micron and 10 microns, concentrations of 15 gr/lt and 30 gr/lt, and polished and blasted textures were used. It was found that this technique is an effective way to produce composite coatings rendering a high number of …

Laser Doppler Velocimetry Research Of The Blowby Gas Characteristics In An Internal Combustion Engine, Mark Kevin Coffill

Masters Theses

The project was designed to measure a reciprocating engine fluid flow (blowby gases past the piston rings) using a laser doppler velocimeter (LDV). Blowby gases were obtained by introducing compressed air into an engine cylinder (piston held at TDC) to simulate engine combustion pressures. Beginning the proposed research included starting an LDV/reciprocating engine laboratory at Western Michigan University and determining the limits of the measurement devices (LDV system in particular).

The limitations which were found in the LDV system only allowed for limited results of in cylinder optical measurements. The results obtained were for cylinder pressures below 0.6 kPa gauge …