Digital Commons Network^™

Petri Net Modeling And Analysis Of An Fms Cell, Paresh A. Patel

Theses

Petri nets have evolved into a powerful tool for the modeling, analysis and design of asynchronous, concurrent systems. This thesis presents the modeling and analysis of a flexible manufacturing system (FMS) cell using Petri nets. In order to improve the productivity of such systems, the building of mathematical models is a crucial step.

In this thesis, the theory and application of Petri nets are presented with emphasis on their application to the modeling and analysis of practical automated manufacturing systems. The theory of Petri nets includes their basic notation and properties. In order to illustrate how a Petri net with …

Effect Of Shrinkage On The Design And Manufacture Of Plastic Parts In Injection Molding Using Cad/Cam Techniques, Deepak M. Shastri

Theses

Computer aided design software in injection molding has revolutionized injection molding in the design and manufacturing processes. Computer Aided Engineering can be applied to injection molding to increase the process efficiency, reduce part costs, and produce accurate parts in less time. The mold designer has many software programs to choose from to produce satisfactory mold designs from part geometries, and a correct selection can produce profitable results. A study of the need for and the scope of computers in injection molding is performed to evaluate the suitability of a CAE package by considering the value added to the parts using …

Analysis Of The Influence Of Natural Wear And Tear In Gates And Runners On The Filling Of A Balanced Multi-Cavity Injection Mold, Ranga Reddy V. Adavelly

Theses

Design of injection molds is outmost important in the manufacture of parts. Its components runners and gates significantly influence the mold filling. Using a simulation package for injection molding a balanced multi-cavity mold was designed. Wear in the gates of runner was simulated by varying the cross-sectional area of the components. Influence of wear of tear in gates of runners on mold filling was measured in terms of flow rate of time of fill. Detailed analysis is done on four different models using four different materials Polycarbonate, Polypropylene, Nylon6 and Polybutylene terephthalate. Graphical display of result is presented and analyzed …

Development Of An Adaptive Fuzzy Shell Clustering Algorithm And Validity Measures, Kurra Bhaswan

Theses

In objective functional based fuzzy clustering algorithms the weighted sum of the distances of the feature vectors from cluster prototype are minimized. The fuzzy memberships are utilized as weighing factors. The cluster prototype can be a point or a line or a plane, etc. This work extends the recent concept of using curved prototypes by utilizing the Adaptive Norm Theorem proposed by Dave¹ to develop an algorithm for the detection of fuzzy hyper-ellipsoidal shell prototypes. The Objective functional associates a norm for each cluster in which to measure the proximity of the shell prototype adaptively. The resulting implementation necessitates …

A Process For Implementing Cim In A Small Manufacturing Facility, Tushar R. Desai

Theses

This work is dedicated to small manufacturing enterprises seeking to explore Computer Integrated Manufacturing (CIM) technology, which is the recent trend in the manufacturing world. The main theme of this thesis is to improve productivity, product quality and reliability, and to reduce costs by integrating various discipline in small manufacturing environment, using computer technology.

To achieve this goal, a hypothetical small manufacturing company was chosen as a subject. The typical functional and organizational structures were analyzed and possible problem areas were highlighted. The problems relating to manufacturing process were studied in detail, and possible solutions were proposed to computerize the …

Computer Graphic Simulation Of Sweeping Of Solid Objects, Jr-Jyun Jang

Theses

This thesis is on the computer graphic simulation of the swept volume of a solid object undergoing Euclidean motions (including translation and rotation). The study helps visualize different types of Euclidean motions and supports the previously developed swept volume theories by providing graphic realism.Included in the thesis presentation are the following :

1. Description of Euclidean motions of polyhedral objects, using ruled surfaces to represent swept volumes.
2. Representation of sweeping of solid objects, -using parametric cubic equation and sweep differential equation.
3. Simulation of motions of PUMA and IBM robots.
4. Wire-frame and shaded image displays of swept volumes.

Numerical Simulation Of The Heating Of Glass Mat Thermoplastic (Gmt) By Combined Conduction And Dual Beam Microwave Source Terms, Shrenik Kasturi

Theses

Fabrication of parts from glass mat thermoplastic involves the heating of the composite to a temperature above the melting point of the matrix iesin to obtain a low viscosity and to allow sheets to be molded without fractui ing. The focus of this work is this heating stage, particularly the influence of a source term in the energy equation.

The solution to this physical situation is complicated by the nature of the GMT sheet, which has a layeied structure, with diffeient thermophysical properties in different layers. The use of source terms has not been reported yet. and is the piimary …

Expert System For Blown Film Extrusion, Jiachyi Li

Theses

Expert systems and blown film extrusion are two subjects to deal with in this thesis. Expert systems are an aspect of artificial intelligence, or a computer's ability to think. The determination of a suitable expert system for particular problem is an important factor in current societies. Blown film is extruded as a continuous tube which is air cooled, collapsed, and wound onto a roll as a double layer of film. Such film, if heat sealed and perforated, makes a roll of bags. There are many factors that affect blown film extrusion. Therefore, using expert system to evaluate blown film extrusion …

Application Of Expert System For Control Of Heating Distribution Network : A Case Study, Jun Li

Theses

The use of an expert system for the heating distribution network is an application of artificial intelligence to the domain of energy engineering.

The development of an expert system for a heating distribution network is explained. The expert system is implemented through the software Kee. The expert system is used to monitor the heating distribution network, and to complement some functions of the controls such as balancing the system pressure, stabilizing output, in addition to fault diagnosis, system process simulation. It serves also as a medium to system moniting, and operator training. Many other functions will be developed on the …

Interfacing Plasticating Extruders With Personal Computers For Data Acquisition, Information Analysis And Retrieval Purposes, Gautamkumar Y. Shah

Theses

The current manufacturing industries are influenced more and more by computers and automation. Two of the major areas of computer uses are data acquisition and interfacing, both lead towards automation.

The intent of this thesis is to focus on the area of interfacing personal computers with plasticating extruders for information retrieval and storage. The requirements for software and hardware are discussed. Analysis of the stored information can be used to improve the quality of the final product. Implications of the stored parameters on the final product are also discussed. A sample program to store and retrieve the important parameters is …

Prediction And Control Of Asymmetric Vortical Flows Around Slender Bodies Using Navier-Stokes Equations, Tin-Chee Wong

Mechanical & Aerospace Engineering Theses & Dissertations

Steady and unsteady vortex-dominated flows around slender bodies at high angles of attack are solved using the unsteady, compressible Navier-Stokes equations. An implicit upwind, finite-volume scheme is used for the numerical computations.

For supersonic flows past pointed bodies, the locally-conical flow assumption has been used. Asymmetric flows past five-degree semiapex cones using the thin-layer Navier-Stokes equations at different angles of attack, freestream Mach numbers, Reynolds numbers, grid fineness, computational domain size, sources of disturbances and cross-section shapes have been studied. The onset of flow asymmetry occurs when the relative incidence of pointed forebodies exceeds certain critical values. At these critical …

Kinematic Synthesis Of Deployable-Foldable Truss Structures Using Graph Theory, Dirk B. Warnaar

Mechanical & Aerospace Engineering Theses & Dissertations

A graph theoretic approach is applied to the conceptual design of deployable truss structures. The characteristics that relate to the inter-connectivity of the elements of a deployable truss structure can be captured in a schematic representation, called a graph. A procedure is presented that enables the exhaustive generation of these graphs for structures of any given number of nodes and links and which are foldable onto a plane or onto a line.

A special type of truss structures, called truss modules, is presented. Graphs of this class of structures form a subset of the graphs of truss structures. Two procedures …

Finite Element Analysis Of Thermal Post-Buckling And Vibrations Of Thermally Buckled Composite Plates, Charles Clifton Gray

Mechanical & Aerospace Engineering Theses & Dissertations

The development of supersonic and hypersonic flight vehicles such as the High Speed Civil Transport and the National Aero-Space Plane has created an increased need for analysis of structures at very high temperatures. Bisplinghoff and Pian, Yang and Han, and Dokmeci and Boley have conducted experimental and analytical studies to determine the effect of elevated temperatures on the vibration characteristics of isotropic plates, Chen and Chen, and Meyers and Hyer have clone studies on thermal buckling and post-buckling of composite plates, respectively.

The thermal loads which will be imposed on the new high speed aircraft will be too great for …

Investigation Of Effects Of Nose Bluntness And Angle Of Attack On Slender Bodies In Viscous Hypersonic Flows, Ashwini Kumar Sehgal

Mechanical & Aerospace Engineering Theses & Dissertations

Hypersonic flows over cones and straight biconic configurations are calculated for a wide range of free stream conditions in which the gas behind the shock is treated as perfect. Effect of angle of attack and nose bluntness on these slender bodies in air is investigated extensively. The numerical procedures are based on the solution of complete Navier-Stokes equations at the nose section and parabolized Navier Stokes equations further downstream. The flow field variables and surface quantities show significant differences when the angle of attack and nose bluntness are varied. The complete flow field is thoroughly analyzed with respect to velocity, …

Simulation Modeling In Manufacturing Cell Design, Debra A. Hunke

Opportunities for Undergraduate Research Experience Program (OURE)

The interwoven phases of the manufacturing process in Computer Integrated Manufacturing (CIM) require a carefully designed facility. Simulation modeling can be combined with other techniques to provide a rigorous methodology for CIM system design. This paper describes CIM, simulation ana their relationship. A case study demonstrates the described methodology in the design of a flexible manufacturing cell.

Maximum Likelihood Estimation For Distributed Parameter Models Of Large Beam-Like Structures, Ji Yao Shen

Mechanical & Aerospace Engineering Theses & Dissertations

Proposed large space structures have many characteristics that give an advantage to modeling their structural dynamics by a set of partial differential equations (PDE's). By far, the most effort put forth in studying system identification and control to date has been based on finite element models. Despite its acceptability, such lumped parameter models have inevitable deficiencies primarily because of their complexity. Both approaches are complementary and each should be used where it is most effective. But the fact is that the distributed parameter approach has not been developed to the level of maturity as for the lumped parameter approach.

Motivated …

On Local Stresses And Spring Constants Of A Sphere-Nozzle Connection, Ban-Li Lyow

Dissertations

This dissertation studies the local stresses and spring constants of a spherical shell with a nozzle attachment when it is under various loadings, namely radial force, overturning moment, horizontal shear force, and torsional moment. Because of the mathematical difficulty in modeling the nozzle-sphere configuration, particularly with nozzle opening, the finite element method (ANSYS package) is utilized in this study. The model used in this study is a quadrilateral thin shell element model when the γ_s (spherical radius/thickness) value is larger than 10. Otherwise the isoparametric solid element is used. The resulting stresses are basically biaxial state of stresses. It …

Some Aspects Of Integration Of Classification, Computer Aided Design, Process Planning, And Scheduling Of Flexible Manufacturing Systems, Suresh Godavari

Theses

This work deals with the role, problems and solution technique for integration of Computer Assisted Design, Classification, Process Planning, and Scheduling for a Flexible Manufacturing System. A lark spectrum of rotational and prismatic parts are considered.

A Knowledge-based rough classification and coding system [C&C] has been developed for coding similar parts using a Group Technology [GT] technique. In this module VP-EXPERT and DBase III Plus are used as expert system and database respectively. This module interfaces with a database for the retrieval and selection process.

The code obtained from the C&C system is the basis for the succeeding phases. The …

Information Handling System With A Personal Computer To Assist In The Manufacturing Of Plastic Parts, Yi Chung

Theses

The ongoing personal computer development has led to its increasing application in manufacturing to improve productivity. Being more aware of this technology, most of these benefits have accrued to large firms. The intent of this thesis is to show that it is equally advantageous for small manufacturing companies to utilize them and show how they can do so.

The field of production control systems is discussed and those areas where personal computers can be applied are emphasized. Forecasting, warehouse management, material requirement planning, and inventory control are the most appropriate. An application example using dBase III plus to write the …

Deposition Of Particles In A Channel With Gravity And Image Forces, Jing-Shiun Lai

Theses

Deposition of particles in a parallel-plate channel under the influence of inertia, fluid viscosity, gravity and image forces was studied using trajectory method.

A laminar fluid flow of uniform and parabolic (or fully-developed) velocity profiles is assumed and the fluid is suspended with particles having the same velocity as the fluid at the inlet plane. The particles flowing into a horizontal parallel-plate channel have no initial velocity in the vertical direction. The influence of gravity force and image force produces a vertical motion which results in deposition of particles on the channel walls.

A trajectory method was employed to find …

Testing The Economic Order Quantity Model On Maintenance Inventory, Teresa J. K. Hall

Graduate Student Work

This pilot study seeks to determine the effect a non-traditional method of inventory control may have on industrial maintenance repair parts inventory. The application of mathematical models designed for production inventory to Maintenance, Repair and Operating (MRO) inventory has not been widely researched, although theorists and practitioners feel there is potential for some models. The Economic Order Quantity (EOQ) theory has proven to be effective in production inventory circles. This pilot study examined the effectiveness of the EOQ in terms of holding cost of the inventory and number of out-of-stock conditions versus the Weighted Moving Average method currently in use …

Automating Tolerance Synthesis: A Framework And Tools, Stephen C.-Y. Lu, Robert G. Wilhelm

Department of Mechanical and Materials Engineering: Faculty Publications

This paper describes CASCADE-T—a new approach to tolerance synthesis that uses a complete representation of the conditional tolerance relations that exist between features of a part under design. Conditional tolerances are automatically determined from functional requirements and shape information. Tolerance primitives based on the virtual boundary requirements approach to tolerance representation are composed to form more complex tolerance relationships. Artificial intelligence techniques, including a constraint network, frame-based system, and dependency tracking are used to support flexible and detailed computation for tolerance analysis and synthesis.

Drainage Of Sandplain Seeps For Salinity Control And Stock Water Supplies, Richard George, Peter Frantom

Journal of the Department of Agriculture, Western Australia, Series 4

Sandplain seeps are derived from a shallow groundwater system which flows from the deep sandplain soils upslope. Seeps result in small areas of salinity and waterlogging, which can be the focus of soil erosion. Sandplain seeps may represent as much as 10 per cent of Western Australia's salt problem in the drier agricultural area. Several drainage experiments conducted between 1986 and 1989 determined the best methods of reclaiming sandplain seeps.

This article discusses the results of these drainage experiments. It comments on the most suitable method for reclaiming sandplain seeps and developing them for stock water supplies.

Whole-Farm Planning : Success At Wilgi Creek, Kevin Shanhun

Journal of the Department of Agriculture, Western Australia, Series 4

Ian and Bev Lynch own Wilgi Creek, a 376 ha mixed farming property at West Mount Barker in the 700 mm rainfall zone. In 1983, they started a whole-farm plan to overcome the problems of declining production caused by waterlogging (their biggest problem), salinity and deterioration of the remnant native vegetation. Today, their property is an example of a successful, wholefarm land conservation plan based on agroforestry, timber production, water harvesting and improved pastures.

Knowledge-Based Support For Management Of Concurrent, Multidisciplinary Design, Raymond E. Levitt, Yan Jin, Clive L. Dym

All HMC Faculty Publications and Research

Artificial intelligence (AI) applications to design have tended to focus on modeling and automating aspects of single discipline design tasks. Relatively little attention has thus far been devoted to representing the kinds of design 'metaknowledge' needed to manage the important interface issues that arise in concurrent design, that is, multidisciplinary design decision-making. This paper provides a view of the process and management of concurrent design and evaluates the potential of two AI approaches—blackboard architectures and co-operative distributed problem-solving (CDPS)—to model and support the concurrent design of complex artifacts. A discussion of the process of multidisciplinary design highlights elements of both …

Petri Net Modeling Of A Flexible Assembly Station For Printed Circuit Boards, M. Zhou, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Petri net modeling approaches are presented for a flexible workstation for automatic assembly of printed circuit boards. In order to improve the productivity of such a system, the building of mathematical models is a crucial step. Concentrating on the operational aspects, the authors construct ordinary and temporal Petri net models for the AT&T FWS-200 physical flexible workstation. Three outcomes follow from such models. First, designers can have a better understanding of concurrency, synchronization, mutual exclusion, and sequential relations involved in the system control from the graphical representations of Petri nets. Second, the performance analysis of system operations under different settings …

Second Coefficient Of Viscosity In Air, Robert L. Ash, Allan J. Zuckerwar, Zhonquan Zheng

Mechanical & Aerospace Engineering Faculty Publications

Acoustic attenuation measurements in air were analyzed in order to estimate the second coefficient of viscosity. Data over a temperature range of 11 C to 50 C and at relative humidities between 6 percent and 91 percent were used. This analysis showed that the second coefficient of viscosity varied between 1900 and 20,000 times larger than the dynamic or first coefficient of viscosity over the temperature and humidity range of the data. In addition, the data showed that the molecular relaxation effects, which are responsible for the magnitude of the second coefficient of viscosity, place severe limits on the use …

Nebraska Summary S111: Lamborghini 115v Dt Also White 6105c And 6105ca, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Test 1642: Ford 3230 (8x2) Diesel 8-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

EXPLANATION OF THE TEST PROCEDURE General Tractors are tested at the University of Nebraska according to the Agricultural Tractor Test Code approved by the American Society of Agricultural Engineers and the Society of Automotive Engineers or official Nebraska test procedure. The manufacturer selects the tractor to be tested and certifies that it is a stock model. Each tractor is equipped with the common power consuming accessories such as power steering, power lift pump, generator, etc., if available. Power consuming accessories may be disconnected only when the means for disconnecting can be reached from the operating station. An official representative of …

Test 1644: Ford 3930 (8x2) Diesel 8-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

EXPLANATION OF THE TEST PROCEDURE General Tractors are tested at the University of Nebraska according to the Agricultural Tractor Test Code approved by the American Society of Agricultural Engineers and the Society of Automotive Engineers or official Nebraska test procedure. The manufacturer selects the tractor to be tested and certifies that it is a stock model. Each tractor is equipped with the common power consuming accessories such as power steering, power lift pump, generator, etc., if available. Power consuming accessories may be disconnected only when the means for disconnecting can be reached from the operating station. An official representative of …