Engineering Commons^™

Finite Element Analysis Of Structures With Constrained Viscoelastic Layer Damping, Yung Chen

Mechanical & Aerospace Engineering Theses & Dissertations

It has been demonstrated that constrained viscoelastic layer damping treatments provide an effective means of passive control for structural vibration. These treatments dissipate vibrational energy by inducing shear strain in a thin layer of viscoelastic material. Our interest is in adding passive damping to a structure as an augmentation to active control. For such applications it is desirable to achieve high damping performance in a given frequency range with a minimum of added weight. Most damping treatments employ spatially continuous constraining layers over the entire viscoelastic layer. Plunkett and Lee have shown that the effectiveness of the damping treatment can …

Navier-Stokes Simulations Of Flows About Complex Configurations Using Domain Decomposition Techniques, Kamran Fouladi-Semnani

Mechanical & Aerospace Engineering Theses & Dissertations

An algorithm is developed to obtain numerical simulations of flows about complex configurations composed of multiple and nonsimilar components with arbitrary geometries. The algorithm uses a hybridization of the domain decomposition techniques for grid generation and to reduce the computer memory requirement. Three dimensional, Reynolds-averaged, unsteady, compressible, and complete Navier-Stokes equations are solved on each of the subdomains by a fully-vectorized, finite-volume, upwind-biased, approximately-factored, and multigrid method. The effect of Reynolds stresses is incorporated through an algebraic turbulence model with several modifications for interference flows. The present algorithm combines the advantages of an efficient, geometrically conservative, minimally and automatically dissipative …

Grid Generation And Flow Computation About A Martian Entry Vehicle, John Edward Stewart

Mechanical & Aerospace Engineering Theses & Dissertations

A number of vehicles are currently being proposed for a manned mission to Mars. One of these vehicles has a modified blunt-nosed cone configuration. Experimental results have been obtained for this vehicle in 1968. These results show lift-over-drag ratios comparable to those needed for Mars entry. Computations are performed here to verify the earlier results and to further describe the flight characteristics of this vehicle.

An analytical method is used to define the surface of this vehicle. A single-block volume grid is generated around the vehicle using an algebraic Two-Boundary Grid Generation algorithm (TBGG) and transfinite interpolation. Euler solutions are …

Transport Matrices Of Finite Beams Resting On Elastic Foundations, M. W. Giger

Tanzania Journal of Engineering and Technology (TJET)

A method of derivation of the coefficients of the transport matrix for a finite element resting on one and two-parameter elastic foundation soils is outlined. The coefficients are summarized for both the Bernoulli–Euler and the Timoshenko beam model in tabular form, for general reference. In addition, bounds on the parameters describing beam/soil flexure, beam and soil shear, which govern the validity of the two-parameter elastic solutions are provided in graphical form.

Force Displacement Relationship For The Prediction Of Structural Fluttering, Ladislaus Lwambuka

Tanzania Journal of Engineering and Technology (TJET)

A new presentation of force displacement relationship for the prediction of structural fluttering is discussed in this paper. This topic is limited to a detailed discussion of the derivation of the equations of motion for the rigid streamlined airfoil/flat plate system of three degrees of freedom, which yields expressions for aerodynamic resultant forces due to a steady air flow. The equations of motion presented herein are derived from the conventional classical complex presentation transformed into real matrix equations. This new presentation of the equations of motion constitutes the foundation for the latest state-of-the-art of predicting critical wind loads on the …

Numerical Investigation Of A Non-Newtonian Material Through A Sudden Pipe Expansion, V. G. Masanja

Tanzania Journal of Engineering and Technology (TJET)

A numerical method for solving two dimensional elliptic boundary-value problems of fourth order is used for finding stationary solutions of the equations of motion for a laminar flow through a sudden pipe expansion of an incompressible non-Newtonian fluid with a constitutive equation of the Reiner-Rivlin (R-R) type. Results for the Newtonian fluid, which is a special case, are in excellent agreement with those by previous investigators and they demonstrate the reliability, superiority and accuracy of the method. Results for the non-Newtonian cases could be of value for fixing ideas about visco-elastic behaviour although the R-R fluid allows only inelasticity: this …

Synergy Of Artificial Neural Networks And Knowledge-Based Expert Systems For Intelligent Fms Scheduling, Luis Carlos Rabelo, Sema E. Alptekin, Ali S. Kiran

Industrial and Manufacturing Engineering

In this paper we describe a hybrid architecture that integrates artificial neural networks and knowledge-based expert systems to generate solutions for the real time scheduling of flexible manufacturing systems. The artificial neural networks perform pattern recognition and, due to their inherent characteristics, support the implementation of automated knowledge acquisition and refinement schemes through a feedback mechanism. The artificial neural network structures enable the system to recognize patterns in the tasks to be solved in order to select the best scheduling rule according to different demands. The knowledge-based expert systems are the higher order elements which drive the inference strategy and …

Color-Rendering Of Daylight From Water-Filled Light Pipes, Florida Solar Energy Center, Ross Mccluney

FSEC Energy Research Center®

Water-filled light pipes can be used to transport concentrated beam solar radiation from a solar collection system to a utilization system, altering the spectral distribution of the radiation in a beneficial way in the process. One use for such a system would be for the daylighting of the core interior spaces of buildings, spaces that are far removed from outside walls or the roof and are therefore not amenable to conventional daylighting with sidelights or toplights. The filtering action of the water can be used to remove unwanted infrared and ultraviolet radiation while affecting the visible portion of the radiation …

Coke Oven Emissions: A Case Study Of Technology-Based Regulation, John D. Graham, David R. Holtgrave

RISK: Health, Safety & Environment (1990-2002)

After examining and analyzing the experience with coke ovens, the authors conclude that attempts to force technology beyond its demonstrated competence can be both expensive and ineffective in controlling hazards. They also suggest implications for pending proposals to further control air pollution.

Parallel Implementation Of A Recursive Least Squares Neural Network Training Method On The Intel Ipsc/2, James Edward Steck, Bruce M. Mcmillin, K. Krishnamurthy, M. Reza Ashouri, Gary G. Leininger

Computer Science Faculty Research & Creative Works

An algorithm based on the Marquardt-Levenberg least-square optimization method has been shown by S. Kollias and D. Anastassiou (IEEE Trans. on Circuits Syst. vol.36, no.8, p.1092-101, Aug. 1989) to be a much more efficient training method than gradient descent, when applied to some small feedforward neural networks. Yet, for many applications, the increase in computational complexity of the method outweighs any gain in learning rate obtained over current training methods. However, the least-squares method can be more efficiently implemented on parallel architectures than standard methods. This is demonstrated by comparing computation times and learning rates for the least-squares method implemented …

Teaching Mechanical Design Using The Axiomatic Approach, Lisa E. Hailey

Theses

Many authors on the subject of design state that it cannot be taught, it must be learned through experience. This thesis offers a method in which design can be taught to senior mechanical engineering students. The axiomatic approach to design, authored by Dr. Nam P. Suh of the Massachusetts Institute of Technology, states that all good designs follow two axioms, the independence axiom and the information axiom. By teaching students to use these axioms, and the corollaries and theorems derived from the axioms, educators can teach students the basic concepts of good design.

To show how this approach can be …

Investigation Of Material Erosion By Abrasive Water Jet Cutting, Fang Hu

Theses

This study is concerned with the investigation of material erosion phenomena occurring in the abrasive waterjet (AWJ) cutting process.

A series of scratches were generated by the abrasive waterjet on the polished surface of aluminum samples. The tests were carried out at different traverse speeds, abrasive flow rates, diameters of sapphire nozzles, diameters of carbide tubes and initial abrasive particle sizes. Material volume loss in the erosion zone was measured directly or calculated by the use of the suggested mathematical models. An analysis of experimental results enabled us to introduce a new process criterion, particle distribution density, which determines the …

Simulation Of Random Packing Of Hard Spheres Using Monte Carlo Method, Sung-Ho Park

Theses

A computer based method of generating a random packing of hard spheres is described. Using a Monte Carlo method as employed in the field of Computational Statistical Physics, packing of hard spheres are generated and analyzed.

The mean packing fractions for the present assemblies of 1000 spheres are 0.555±0.015 after pouring and 0.582±0.018 after 10 cycles of shaking. These values are approximately 5 to 6 per cent lower than the experimental results of G.D. Scott[30], but similar with the result of Visscher & Bolsterli [17].

The mean coordination numbers are 5.97 and 6.33 for the pouring and shaking case, respectively. …

Finite Element Stress Analysis Of Engine Piston, Anil Nanalal Mistry

Theses

In this analysis, Ford Motor Company's, modular engine seriespiston was selected for the analysis purposes. The engine has a capacity of 4.6 liter, V-8 cylinder and with 2 valves.The piston is made of aluminum alloy material Z-16-T6. A three-dimensional finite element model was created to analyze the piston. The model, which contains only the quarter section of the piston due to loading symmetry and geometry, was used to calculate operating temperatures and the corresponding thermal expansion. Operating stresses due to thermal and mechanical loads were also calculated. The accuracy of the model was verified by material data published in the …

Modeling Packed Bed Catalytic Reactors, Jing Yang

Theses

Catalytic reactors provide a potentially important tool in the control of process emissions to the environment. This work provides a detailed chemical/physical model for analysing the operational characteristics of packed bed catalytic reactors. Mass, momentum, and energy conservation equations are written for the gas and solid phases. Heterogeneous and homogeneous reactions are used to convey the required stoichiometry, reaction rate, and heat release rate. Reaction in each phase is modeled as a one-step, global reaction. Heat and mass transfer, fluid friction, and axial heat conduction in the solid phase are modeled using suitable literature correlations. The resulting non-linear, first-order differential …

Development Of Air-Break Circuit Breaker, Ravi Kanth Korrapati

Theses

This thesis describes the development of an Air-Break circuit breaker, for Heinemann Electric Co., New Jersey, using I-DEAS CAD software. The physical properties obtained from the software, for the components of the armature assembly and the contact arm and the carriage, are used in determining the initial forces on a helical delay spring and in calculating accelerations of links in the trip mechanism. The trip mechanism is a four-bar mechanism with a spring as a coupler. Two second order differential equations define the motion of its links, the contact arm and the carriage. A time history of the links is …

A Comparative Study Of Edge Detection Techniques, Jaskaran Singh Dhaliwal

Theses

The problem of detecting edges in gray level digital images is considered. A literature survey of the existing methods is presented. Based on the survey, two methods that are well accepted by a majority of investigators are identified. The methods selected are: 1) Laplacian of Gaussian (LoG) operator, and 2) An optimal detector based on maxima in gradient magnitude of a Gaussian-smoothed image. The latter has been proposed by Canny[], and will be referred as Canny's method. The purpose of the thesis is to compare the performance of these popular methods. In order to increase the scope of such comparison, …

An Investigation Of The Dynamics Of Abrasive Waterjet Formation, Md. Ekramul Hasan Khan

Theses

The aim of this research was to investigate the jet formation and the jet behavior, as characterized by the velocity field, the force exerted by the jet on a work-piece and the jet geometry. The velocity and force distributions were measured using a laser transit anemometer (LTA) and a piezoelectric force transducer (PFT) respectively for constant water pressure (334.6 MPa) supply. The jet structure and its instantaneous behavior were visualized by the used of high speed filming. LTA and PFT measuring techniques were established and verified. The measurements were performed under different operating conditions. It was found that at a …

Statistical Process Control For High Precision Deep Drawn Sheet Metal Parts, Sunil S. Shah

Theses

In today's world, industrial expertise has come to be judged in terms of the quality of the product. Good quality has become the ultimate aim in a manufacturing environment, which leads to many innovations for ease in the inspection of parts. In considering a metal working company like Hudson Tool & Die Company, a study of the various operations and the application of Statistical Process Control to the forming operations is performed using STORM software. Important characteristics have been carefully studied with regards to metal forming like uniform metal thickness, radius of the bend, depth of the drawing operation. In-depth …

Adhesion Effects In Micro Mechanisms, Dennis Alan Kalgren

Theses

Dielectric resonators (DR) are suitably shaped objects made of high dielectric constant materials like TiO2, BaO, ZnO, and accessory ingredients, which can function as electrical resonators covering a very wide frequency range upto 40GHz. The physical dimensions of dielectric resonators are in mm range. High dielectric constant material resonators seem to be ideally suited for microwave applications because of their miniature size, low loss, insensitivity to magnetic dc biasing fields, and ability to concentrate large RF magnetic fields in small volumes. However temperature stabilization of dielectric resonators is an important consideration as the center frequency is a function of temperature. …

Design Of Spatial Linkages For Dwell Function Generation, Donald F. Kelly

Theses

Certain single-loop spatial linkages containing spherical pairs may be used as dwell function generators. Analysis and design of these linkages, however, may be too complex for the practicing engineer.

In this study a method is presented, where the set of link lengths representing a linkage are determined from a smaller set of design parameters. Graphical relationships are also found between the design parameters and functional requirements for dwell, such as output function amplitude and dwell range. These graphs may be used as design charts, and design becomes the calculation of link lengths from design parameters chosen to satisfy the functional …

Selection Of Master Degrees Of Freedom In Model Reduction Techniques, Yixing Qi

Theses

Based on the model reduction technique called SEREP (System Equivalent Reduction Expansion Process), systematic ways to select the master degrees of freedom (the degrees of freedom kept in the reduced model) are developed and their usefulness is demonstrated by the examples. The following two criteria are ' developed for two specific objectives.

When we need to identify the response of the full model from the response of the reduced model (usually obtained from the experiments,) we hope to reduce the estimation error between the estimated response and the actual one. We also hope to keep the points which will have …

Modification Of Turret For Enhancement Of Internal Turning Operations On A Cnc Lathe, Talla Rajasekhar

Theses

Towards the modification of the CNC turret a complete set of tool holders have been designed. They have been manufactured and installed according to the specifications. A detailed study of MARK CENTURY 2000 controller and PartMaster is presented. Additionally a component has been designed to be machined on the CNC lathe utilizing the MC2000 part programming capabilities. The part program of the machine component has been developed utilizing various phases of MC2000's Partmaster software. The generated part program has been executed on the CNC lathe.

Effective Use Of Management Information Systems In Manufacturing, Bhavik Shah

Theses

Information is the catalyst of management and the ingredient that coalesces the managerial functions of planning, organizing, actuating and controlling. The implementation of management information system (MIS) provides the vehicle by which management process can be administered and integrated. Information is at the core of creative thinking, which leads to new ways of improving products, process and services to the invention of new devices and to discovery of new marketable concepts. Thus information for an organization has a dual application for internal operation and external marketing potential.

The organization studied was a small to medium sized batch manufacturer of healthcare …

The Optimal Design Process : Integrating Creativity And The Axiomatic Approach, John V. P. Tirrell

Theses

This thesis will show that the optimal design process incorporates both creativity and the axiomatic approach. An examination of past and current design methods will substantiate the need for the integration of these components. Creativity is the designer's tool to produce innovative designs which transcend existing design solutions. Creativity is also an integral element of the axiomatic approach to design. In the axiomatic approach, two design axioms are applied to efficiently ascertain the best design solution from the infinite number of choices. Application of the design axioms, theorems, and corollaries streamlines the design process. The integration of creativity and the …

Cad/Cam : An Analysis And Application To An Industrial Environment, Kulendu Vyas

Theses

This work is intended to explore details of CAD/CAM techniques and to check its application in medium size industry. To achieve this goal, a thorough study has been carried out on current CAD/CAM techniques, keeping in mind it's requirements, source and application, considering both the hardware and software side of it. To check application of CAD/CAM in an industrial environment, Schering Plough corporation was chosen as a subject. The main theme behind this application to the Schering Corp. was to develop the CAD/CAM capability within company, in order to gain better control over the quality and productivity, and to reduce …

Computer-Aided Planning For Automatic Assembly Of Printed Circuit Boards, Qin Xiang

Theses

A study of printed circuit board assembly in the context of process planning and optimization of assembly motion is presented. A knowledge-based system is developed utilizing software packages VP-Expert, dBase 3 for the Universal automatic assembly machines. The planning of time-optimal assembly motion falls into the travelling salesman problem whose solution is obtained using a composite algorithm. Branch-and-bound algorithm is also discussed for solving the travelling salesman problem.

A Suggested Model Program For Cim Education, Sema E. Alptekin

Industrial and Manufacturing Engineering

No abstract provided.

Adaptive Scheduling And Control Using Artificial Neural Networks And Expert Systems For A Hierarchical/Distributed Fms Architecture, Luis Carlos Rabelo, Sema E. Alptekin

Industrial and Manufacturing Engineering

An adaptive expert scheduler was developed that learns by itself and adapts to the dynamic FMS environment. This hybrid system uses a symbiotic architecture composed of expert systems (ESs) and artificial neural networks (ANNs) and provides a learning scheme guided by past experience. The artificial neural networks recognize patterns in the tasks to be solved in order to select the best scheduling rule according to different criteria. The expert systems, on the other hand, drive the inference strategy and interpret the constraints and restrictions imposed by the upper levels of the control hierarchy of the flexible manufacturing system. The level …

Thermoelastic Problems Of Multilayered Cylinders, Victor Birman

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Thermoelastic problems of long multilayered cylinders manufactured from isotropic materials are considered. The steady-state thermal field corresponding to a constant difference between temperature outside and inside the assembly is used in the analysis. Both the case of a hollow cylinder and that of a solid multilayered assembly are discussed. A closed-form exact solution is shown for an arbitrary number of layers if the properties of constituent materials remain unaffected by temperature. Various strategies leading to an analytical solution are proposed for the case where material properties depend on temperature. The stresses in a dual-coated optical fiber subject to a uniform …