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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.

Development of a manufacturability analysis system for reinforced plastics components

Marquez Robledo, Miguel A. January 2001 (has links)
This thesis describes the research and development of a systematic and consistent methodology to perform manufacturability analysis of Reinforced Plastic Parts (RPP). The proposed methodology evaluates the part model in the early stages of the product development process considering the capabilities and constraints of available manufacturing processes, materials and tooling required in standard RPP production. Critical Manufacturing Part Features (CMPF) are identified and the relationship between the model's geometrical information, the expert's geometric reasoning, and the knowledge about the involved manufacturing processes are clarified and set together in an efficient feature-rule-based manufacturability analysis system. The prototype system named 'FEBAMAPP', combines solid modelling (SM), automatic feature recognition (AFR), object oriented programming (OOP), and a rule-based system (RBS) in order to assess the manufacturability of the proposed design. The novelty of this research is based in the use of a Face Vector (FVector) concept to transform geometrical and topological information of the solid model into a suitable input data to be used in the Neural Network Feature Recognition System. Further novelty arises from the fact that this is the first attempt to use neural networks in the recognition of 3-D features in hollow parts including the presence of fillets along the edges of the part. The manufacturability evaluation can be performed considering different combinations of materials along with different manufacturing processes giving the designer the opportunity of selecting an appropriate combination for any specific application. Promising results have been obtained during the test of the system, where 100 % recognition of trained features with 90% confidence has been achieved. Also, good results have been obtained in the recognition of non-trained features such as the Cross-Slot feature, which is recognised as a Slot feature. After automatic feature recognition, Manufacturability Analysis is focused on internal and external characteristics of the model's features, where potential manufacturing difficulties are identified and feedback in terms of design suggestions is then used to advise the design process and improve the overall manufacturability of the part. This manufacturability evaluation in terms of internal and external characteristics of the features has proved to be efficient in detecting detailed design errors that can be costly in further manufacturing stages in the product development process.

Non-photorealistic rendering : a critical examination and proposed system

Schofield, Simon January 1994 (has links)
In the first part of the program the emergent field of Non-Photorealistic Rendering is explored from a cultural perspective. This is to establish a clear understanding of what Non-Photorealistic Rendering (NPR) ought to be in its mature form in order to provide goals and an overall infrastructure for future development. This thesis claims that unless we understand and clarify NPR's relationship with other media (photography, photorealistic computer graphics and traditional media) we will continue to manufacture "new solutions" to computer based imaging which are confused and naive in their goals. Such solutions will be rejected by the art and design community, generally condemned as novelties of little cultural worth ( i.e. they will not sell). This is achieved by critically reviewing published systems that are naively described as Non-photorealistic or "painterly" systems. Current practices and techniques are criticised in terms of their low ability to articulate meaning in images; solutions to this problem are given. A further argument claims that NPR, while being similar to traditional "natural media" techniques in certain aspects, is fundamentally different in other ways. This similarity has lead NPR to be sometimes proposed as "painting simulation" — something it can never be. Methods for avoiding this position are proposed. The similarities and differences to painting and drawing are presented and NPR's relationship to its other counterpart, Photorealistic Rendering (PR), is then delineated. It is shown that NPR is paradigmatically different to other forms of representation — i.e. it is not an "effect", but rather something basically different. The benefits of NPR in its mature form are discussed in the context of Architectural Representation and Design in general. This is done in conjunction with consultations with designers and architects. From this consultation a "wish-list" of capabilities is compiled by way of a requirements capture for a proposed system. A series of computer-based experiments resulting in the systems "Expressive Marks" and 'Magic Painter" are carried out; these practical experiments add further understanding to the problems of NPR. The exploration concludes with a prototype system "Piranesi" which is submitted as a good overall solution to the problem of NPR. In support of this written thesis are : - • The Expressive Marks system • Magic Painter system • The Piranesi system (which includes the EPixel and Sketcher systems) • A large portfolio of images generated throughout the exploration.

Configuring simulation models using CAD techniques : a new approach to warehouse design

Brito, A. E. S. C. January 1992 (has links)
The research reported in this thesis is related to the development and use of software tools for supporting warehouse design and management. Computer Aided Design and Simulation techniques are used to develop a software system that forms the basis of a Decision Support System for warehouse design. The current position of simulation software is reviewed. It is investigated how appropriate current simulation software is for warehouse modelling. Special attention is given to Visual Interactive Simulation, graphics, animation and user interfaces. The warehouse design process is described and common difficulties are highlighted. A Decision Support System (DSS) framework is proposed to give support during all the warehouse design phases. The use of simulation in warehouse design is identified as being essential for evaluating different warehouse configurations. Several simulation models are used to show that the warehouse systems special characteristics require a new way of defining the simulation model and new modelling elements to represent the complex logic of a warehouse system. AWARD (Advanced WARehouse Design) is a data-driven generic model, developed to build warehouse simulation models. It uses Computer Aided Design (CAD) techniques for drawing the warehouse layout and configuring the simulation model. The user has no need for programming skills and a user-friendly interface makes it easy to use. High resolution colour graphics and a scale drawing of the warehouse makest he dynamic display of the model a good representationo f the real system. Several examples illustrate the use of the AWARD system. The experience and advantages of the AWARD approach is discussed and the extension of this approach to other areas is explored.

Formex configuration processing of compound and freeform structures

Moghimi, Mahdi January 2006 (has links)
No description available.

Load balancing for parallel 3D visualisation

Maselino, Prince January 2006 (has links)
No description available.

The development of a framework for inter-diciplinary building design working, and the application of intelligent knowledge-base system techniques

Yamakawa, Shigeki January 1997 (has links)
This work aims at establishing a framework for inter-disciplinary building design working, and developing a computer-based design aid which demonstrates the framework as well as enhancing the effective use of design information using intelligent knowledge-based system (IKBS) techniques. Design activities were initially discussed in logical terms taking account of stereotypes as starting points for design solutions. A conceptual model of design activities was then proposed, where these were characterised in terms of three different features, i.e. information, design decision and performance. Subsequently, the building design process was structured into a hierarchy of design issues and design tasks, and was then described rationally, relating to the conceptual model, in terms of three kinds of design variables, i.e. information, design decision and performance variables. The information regarding the design process was, meanwhile, elicited from publications with particular reference to daylighting and lighting design aspects, and itemised into a number of knowledge units. Based on this information, a framework for inter-disciplinary building design working was eventually developed, where design activities are considered in terms of the relationships between the design variables, and, as a result, a logical sequence of the design process was established. In order to clarify the parallel inter-disciplinary aspects of the building design process, the design knowledge was examined based upon the framework, and, eventually, developed into a checklist for inter-disciplinary building design working which has a process-checking capability. Subsequently, a prototype knowledge-based system was developed on the basis of the framework, using a commercially available expert system shell, Leonardo. Examples of stereotypes also formed a part of its knowledge. Demonstrating the checklist for inter- disciplinary design working, this prototype knowledge-based system proved the viability of the checklist approach, as well as showing its process checking capability. It also exhibited its potential ability to provide appropriate information at pertinent stages.

Geometry based constructions for curves and surfaces

O'Neill, Edward Finbar January 1993 (has links)
No description available.

The application of computer-aided-analytical techniques in the investigation of fundamental aspects of centrifugal pump design

Thackray, Paul Rhodes January 1994 (has links)
No description available.

An investigation into 3-dimensional garment pattern design

Chen, Jocelyn Hua-Chu January 1998 (has links)
No description available.

Intelligent CAD mould design for injection moulding

Masuku, Eric S. January 2000 (has links)
No description available.

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