Mechanical Engineering Commons^™

Improvement Of Waterjet And Abrasive Waterjet Nozzle, Zheng Li

Dissertations

This investigation is concerned with the improvement of the nozzle design for water and abrasive water jet machining. The mechanism of formation and characteristics of pure water and abrasive water jets are investigated in order to determine quasi-optimal process conditions.

To improve the pure water jet machining, a pulsed water jet nozzle, which employs the principle of the Helmholtz type resonator, is investigated experimentally and numerically. The experiments show the advantages of this nozzle over the commercial nozzle in cutting and cleaning. A numerical solution of the differential equations of continuity, momentum conservation, turbulent kinetic energy and dissipation for two …

Local Thermal Stress Factor Of Pipe-Nozzle, David Chihwei Chen

Dissertations

A comprehensive study of local thermal stresses at the juncture of pipe-nozzle is presented in this thesis. The thermal loading is assumed to be a linear thermal gradient across the thickness of the pipe and nozzle. Currently, there exists neither experimental nor analytical data that is sufficient for pressure vessel designers to analyze the local thermal stresses at the juncture of pipe-nozzle. In order to provide a comprehensive database to calculate these thermal stresses, the finite element technique is used to provide a series of local thermal stress factor plots as a function of pipe-nozzle geometrical parameters.

For the local …

Local Stress Factors Of Pipe-Nozzle Under Internal Pressure, Jih-Lian Jack Ha

Dissertations

This thesis presents a comprehensive study of local stresses around a pipe-nozzle due to internal pressure. The finite element method (FEM) was employed to provide a numerical solution which will furnish a database for stress analysts to compute local stresses of pipe-nozzle due to internal pressure. The local pressure stresses for both the pipe and the nozzle around the pipe-nozzle juncture are first normalized into pressure stress factors which are then plotted as functions of geometrical parameters, beta, β, (nozzle mean radius / pipe mean radius) and gamma γ, (pipe mean radius / pipe thickness). These local pressure stresses at …

Particle Dynamics Modeling Of Vibrating Granular Beds, Yidan Lan

Dissertations

Particle dynamics modeling is done to study the behavior of granular beds subjected to vibrations imposed by a plane boundary which oscillates sinusoidally about a zero mean speed. Significant differences between the lower and higher shaking acceleration regions are found for the granular temperature and solids fraction depth profiles, which characterize the effectiveness of the boundary in fluidizing the beds. When higher accelerations are applied, the temperature is maximum at the vibrating floor and attenuates through the depth, while the solids fraction profiles exhibit a maximum at some intermediate depth. At lower acceleration values, most of the mass is located …

Adaptive Nonlinear Control Using Fuzzy Logic And Neural Networks, Shu-Chieh Chang

Dissertations

The problem of adaptive nonlinear control, i.e. the control of nonlinear dynamic systems with unknown parameters, is considered. Current techniques usually assume that either the control system is linearizable or the type of nonlinearity is known. This results in poor control quality for many practical problems. Moreover, the control system design becomes too complex for a practicing engineer. The objective of this thesis is to provide a practical, systematic approach for solving the problem of identification and control of nonlinear systems with unknown parameters, when the explicit linear parametrization is either unknown or impossible.

Fuzzy logic (FL) and neural networks …

An Interactive Computer Graphics Based Off-Line Avail Programming Environment For Coordinate Measuring Machines, Nayanesh B. Bhandutia

Theses

Productivity can be increased by providing computer aided off-line program development environment to operate direct computer controlled Coordinate Measuring Machines (CMM). Such an environment not only results in reduced operational downtime of the CMM but also eliminates the need for the operators to learn and debug the complicated CMM programming language.

An application software was developed to provide a computer based graphical environment for on-the-screen CMM inspection simulation and AVAIL part program development. A comprehensive, menu driven front-end was developed as a foundation for this software. Algorithms were designed and coded to read and interpret CAD software part design information …

Automatic Feature Extraction From Conventional Cad Model To Support Feature-Based Design Approach For The Sheet Metal Stamping Industries, Dipak P. Thakar

Theses

Despite the continuing improvement in computer aided design (CAD) systems and improvements in computer aided manufacturing (CAM), the process planning activity has still not been completely integrated into the CAD/CAM cycle. Particularly in sheet metal stamping industries human interpretation of CAD data is required to extract the geometry and technological information of a component. As a result most CAD systems are used as advanced drafting and drawing management tools by designers. Thus the responsibility for interpreting the design data required for extracting the manufacturing part features still resides with the process planner. Which has increase possibilities of entering errors with …

Dynamic Friction Measurement, Atif Aly

Theses

The friction force between two bodies sliding at constant relative velocity is a function of their relative velocity. Under conditions of time-variable relative velocity, the instantaneous friction is a function not only of the instantaneous velocity but also the velocity history. An understanding of the resulting dynamic friction function will allow for the design of control systems where velocity is time-varying, oscillatory andoften contained in a relatively small region centered around zero amplitude. Within the control system, a portion of the control force can be implemented to effectively counteract the friction present and allow for precise motion control.

In this …

Kinematic And Kinetic Analysis Of Geneva Mechanisms And Their Applications To Synchronization Of Motion, Bijan Sepahpour

Theses

Geneva mechanisms have been used for generating intermittent motion for use in indexing and packaging operations. Due to their popularity, cost effectiveness and diversified applications in industry, it is desirable to optimize their design.

Optimization techniques and modifications have been developed to provide long life, trouble-free high-speed indexing and intermittent motion while minimizing the undesirable inherent dynamic characteristics of this class of mechanisms.

A general information base of the motion characteristics and types of geneva mechanisms available has been established. Development of the full spectrum of the required equations, generation of the normalized values of critical design parameters along with …

An Integrated Approach To Implement Iso 9000 Series Standards To United States Manufacturing Industry, Jatin N. Amin

Theses

Implementation of ISO 9000 series quality system standards to the U.S. manufacturing industry is discussed by developing a generic model for implementation. In recent past, quality became a prime performance issue to formulate strategy to improve market share and profit for U.S. manufacturing industry. Many companies seeks for ISO 9000 registration. Manufacturing industry and other industries as well, are facing numerous problems in implementing ISO 9000 quality system standards. At present, about 400 U.S. companies have gained certification under this standard.

In this work an attempt has been made, to highlight problems which are most likely to be critical to …

Implementation Of Continuous Flow Manufacturing In United States Industries, Rohit P. Patel

Theses

Continuous Flow Manufacturing (CFM) is one of the key strategies to enable the United States industries to adapt to any volume increase and rapidly changing requirements of the market place. CFM is an on-going analysis and improvement activity used to optimize the efficiency, effectiveness and flexibility of any process. The two basic goals of CFM are to reduce cycle time to less than customer order leadtime and to eliminate inefficiencies from the overall manufacturing processes.

The thesis will describe reasons for the scarcity of CFM in United States industries. The methodology applied was a detailed six page questionnaire sent to …

Remediation Of Contaminated Sites Using Hot Gas Injection, Sanjay Jayabal

Theses

Remediation of contaminated subsurface sites at lower cost and time than currently used technologies are being demonstrated for a systems concept using new technology developed at the Hazardous Substance Management Research Center at New Jersey Institute of Technology. A technique for pneumatic fracture is employed to "open" subsurface passages to enhance vacuum extraction of contaminants. Economical and environmentally sound destruction of these contaminants is then accomplished using catalytic oxidation followed by scrubbing to remove air pollutants. The hot gas from this phase of the process is then injected into the subsurface formation after being used to preheat the fuel/air mixture …

Motion Synthesis Of Mechanisms Using Constraint Manifolds In Image Space, Yeou-Kai Wu

Dissertations

Kinematic mappings, quaternion algebra, and constraint manifolds in the algebraic image space are applied to the problems of the dimensional synthesis of mechanisms. Dimensions of a mechanism are determined such that a tracer frame fixed on the coupler will pass through or at least as close as possible to the desired positions and orientations in the physical space as the input link rotates about its fixed joint. First, using kinematic mappings, the desired positions and orientations of the tracer frame of the mechanism can be mapped onto points in a hyperspace in which the motion of the tracer frame can …

Numerical Investigation Of Flow Through Wide Angle Diffusers, Moududur Rahman

Dissertations

This study is aimed at the development of a computational technique for the prediction of the flow field in wide angle diffusers. The finite element technique is used for the solution of the governing equations. A commercial software package, NISA/3DFlUID, modified for this specific application was used. The parameters affecting the flow field have been identified. For a wide range of variation of these parameters, the effects on the flow field have been examined. This investigation is an exhaustive and comprehensive numerical study of diffuser flows. Such a study will result in substantial improvement in the understanding of the anatomy …

An Investigation Of The Formation Of Turbulent Water And Abrasive Water Jets, Md. Ekramul Hasan Khan

Dissertations

This study is concerned with the development of a knowledge base for the selection of nozzle geometry by investigating the mechanism of formation and behaviors of water and abrasive water jets. A numerical prediction of turbulent water flow inside various nozzles is developed. The analysis is based on the numerical solution of conservation equations of continuity and momentum as well as equations of turbulent kinetic energy and dissipation for 2-dimensional axisymmetric flow by using a finite element package, FIDAP.

The technique for determining velocities and forces of water jet and abrasive water jet with the Laser Transit Anemometer and Piezoelectric …

Computer Aided Stress Analysis Of The Femur With Prosthetic Hip Stem Utilizing Computed Tomography, Wei-Chun Chang

Dissertations

A computer aided design and analysis method, utilizing computed tomography (CT) is developed, which together with a finite element program determines the stress and deformation patterns in the femur with hip prosthesis. The CT scan data file provides the geometry and the material parameters for the generated finite element model. The three-dimensional finite element model of the femur with hip prosthesis is automatically generated from the CT data file by a preprocessing procedure. The preprocessor includes a CT image display, edge detector, nodes generation, prosthesis simulator, mesh generator and model display. The loading conditions applied on the finite element model …

Base Plate Placement For A Predefined Workspace Of A Stewart Platform Parallel Manipulator, Rajesh Chanda

Theses

This thesis deals with solving the problem of placing the base plate in an optimum position and orientation in a three dimensional space for the desired locations of the mobile end platform of a Stewart platform parallel manipulator.

First the workspace of the mobile plate is expressed as a function of the base plate position. Then the objective function is generated by summing the squared distances from the various desired locations of the mobile plate to the center of the platform's workspace. This function consists of six unknown variables which define the position and orientation of the base plate. A …

Development Of A Non-Intrusive Particle Motion Tracking Technique For Granular Flow Experiments, Jerry R. Volcy

Theses

Implementation aspects of monitoring the position and orientation of a one-inch diameter particle in space non-intrusively based on the principle of magnetic induction coupling are discussed. A radio-transmitter embedded within the particle induces voltages in receiver antennae. Position and orientation of the particle are deciphered from these voltages. A previously developed math model that predicts the voltage induced in an antenna given the position and orientation of the transmitter with respect to the antenna as well as the numerical techniques used to obtain the inverse solution of computing position and orientation from a given set of voltages are used.

Practical …

Measurement Of Velocity Of A High Speed Waterjet, Chang-Hsin Yu

Theses

In order to maximum the productivity of water jet cutting and cleaning. The determination of the particle velocities at different conditions of water jet formation is essential to the establishment of a prediction model of the cutting results.

The Study is Intended to develop an interface between Laser Transit Anemometer (LTA) and IBM PC for velocity field measurement of the jet by automation of technology design. To achieve this, a turbo basic program is developed to link LTA, counter processor, NIC-320 nicolet oscilloscope and IBM PC together for improve the efficiency and quality of velocity's measurement of the jet.

Because …

Analysis For Handling Flexible Green Sheets With Automated Tools, Chao Xie

Theses

The electronics industry is characterized by rapid technological advances. Increase in number of I/O interconnections on chips and need for more compact assemblies is forcing designer to consider multilayer ceramic packaging. With the advancement in co-fired technology, the green tapes are becoming widely used now, and will be even more so in the future. There is considerable knowledge and expertise on the preparation of multilayer ceramic materials but little information is available on the handling of laminate ceramic green sheets with automated tools.

In this thesis, we will analyze the displacement, the principal and shearing stress of the different sized …

Design Of An Autonomous Vehicle System, Fritz Gerald Momplaisir

Theses

With advances in electronics, mobile vehicles are becoming more and more sophisticated. The Potential applications of AGVs are numerous an range from a material handling system for the factory floor to an intelligent wheel chair for the handicapped. The design of these vehicles, however, remains a difficult task. Even when the machine is given precise information about its environment, the fact that it is never free of noise further complicate the situation. One of the goals of an AGV project is to design a robust system that will operate efficiently in the presence of different sources of noise.

The scientific …

An Integrated Mrp And Finite Scheduling System To Derive Detailed Daily Schedules For A Manufacturing Shop, Sita D. Nathan

Theses

Many companies rely on Material Requirements Planning (MRP) to support their Production Scheduling and Control (PS&C) functions. Since MRP does not provide a detailed shop floor schedule, these users have to implement either a third party procedure or an internally developed procedure for shop floor controls. In this thesis we consider a class of user shops which are characterized by the following features:

• Homogenous machines, that is all machines can produce all products.

• Each product requires a setup, but several products may have a common setup.

• MRP requirements are specified on a weekly basis while actual requirements are specified on …

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Semi-Automated Approach To Shape Optimal Design Of Planar Structures, Gurinder Pal Singh

Theses

This paper presents a general algorithm, using IDEAS programmability features to integrate different phases of shape optimization process. The present work is mainly concentrated on planar structures, defined by thin or shell finite elements. Interactive programs are generated to convert input data to geometric models, to define mesh areas, to generate finite element mesh and to execute adaptive mesh refinement techniques. The importance of automated mesh generation and refinement is highlighted and various optimization methods are considered. Further, a special attention is given to integration issues of shape optimization capabilities into CAD environment. To demonstrate the developed algorithm, an automotive …

Machining Of Silicon Wafers With An Abrasive Water Jet Cutter, Frank J. Marciniak

Theses

This thesis consists of a study of the effects of abrasive water jet cutting on brittle silicon substrates. In total, 26 different cuts were made in a single crystal silicon substrate with an abrasive water jet cutter under different conditions of water flow, water pressure, and abrasive flow rate. These cuts were analyzed for surface roughness, and microstructure.

The roughness measurements were compared in order to determine the best possible cutting conditions. The cut with the best roughness of 0.000170 inches was obtained under cutting conditions of 30 KSI water pressure, 1 inch/minute cutting speed, and an abrasive flow rate …

Prediction Of Linear And Non-Linear Components Of Cutter Deflection In End Milling Tools, Kimberly Nazimek

Theses

In this study, cutter length, cutter diameter, depth of cut, and magnitude of the instantaneous force vector are examined to determine their effects on cutter deflection during end milling. Their contributions to both linear and non-linear cutter deflection are examined. Models are developed to compute deflection for both flat and ball end mills. These models are evaluated to determine the contribution of each type of deflection encountered during a variety of milling conditions. A discussion on the transfer of deflection data to an estimation of machining accuracy is then presented.

Concurrent Engineering And Design For Manufacture In The Medical Device Industry, Martin A. Mathelier

Theses

Concurrent Engineering (CE) is an approach to product development in which engineers work on design and manufacturability at the same time. The ultimate goal of concurrent engineering is to reduce the time-to-market while improving quality. This thesis goes into details about the tools necessary to achieve successful product development in the Medical Device Industry. The novelty of this thesis is not in the tools themselves but rather in the way that they are applied to the medical device industry. The need for the CE approach is of utmost importance because of the vast competition in the medical device industry.

The …

A Knowledge-Based Designer Assistant System With Application To The Design Of Helical Springs, Giridhar Raja

Theses

Design problems are generally difficult to solve because the domain of solutions is often infinite (like design of gears, bearings, shafts, springs etc.) and generally requires several iterations before we can arrive at the right solution. The search for the right solution satisfied by several constraints is also time consuming. Thus design intrinsically requires backtracking and several iterations to obtain the desired solution.

In the design of helical springs where the load, deflection, allowable stress, and material are specified, there are an infinite number of solutions. If, in addition to these requirements, the mean coil radius, wire diameter, free height …

A Survey Of Manufacturing Practices In Southeast Asia, Fe Irma A. Ramirez

Theses

This paper presents a study of the current manufacturing practices in Southeast Asia particularly Indonesia, Malaysia and the Philippines. This region is regarded as the next region to watch in terms of economic performance and potential. A mail survey of manufacturing companies in these countries was performed in order to get the data. A six-page questionnaire was sent and covered the following areas: company profile, production control and management, quality management and automation and computerization. Majority of the respondents were medium- and large scale companies and carried a wide array of products. Most of the firms were labor intensive rather …