Gordon Blount

Carbon-carbon composites: a summary of recent developments and applications

Abstract Carbon Fibre Reinforced Carbon (CFRC), or Carbon-carbon, is a unique composite material consisting of carbon fibres embedded in a carbonaceous matrix. Originally developed for aerospace applications, its low density, high thermal conductivity and excellent mechanical properties at elevated temperatures make it an ideal material for aircraft brakes, rocket nozzles and re-entry nose tips. It withstands temperatures in excess of 2000°C without major deformation. The properties are very much dependent on the manufacturing methods used for production. Although the general production technology is known, the combination of processes to achieve specially tailored properties remains the expertise of particular manufacturers. This paper reviews major developments of Carbon-carbon composites and describes actual and future applications. Improved oxidation resistance and continuously decreasing manufacturing costs make this family of materials more and more attractive to high performance applications as well as for general engineering design.

The suitability of aluminium as an alternative material for car bodies

Abstract Aluminium is most likely to play a more important role in future car generations. Its material properties give it some advantages and open the way for new applications in the automotive industry. One of these is its use in car bodies. As car bodies contribute to approximately 20% of the total weight of a car they offer a promising way to reduce the weight of cars considerably. This article investigates the difficulties and opportunities associated with aluminium. The article reflects on manufacturing issues and cost aspects as well as with ecological aspects, safety and repairability of aluminium car bodies.

An approach to the EuP directive and the application of the economic eco-design for complex products

Current changes in European Union legislation forces design engineers to incorporate sustainable thinking, environmental protection and eco-design into their design considerations. Many companies are concerned that integrating the eco-design principle into their product design process could result in increasing product cost and a loss of their competitive edge. Within this paper recent and possible future developments of the ‘eco-design of energy using products’ (EuP) Directive are discussed as well as the effects this has on companies. The main outcome of this research is the development of a design decision methodology that helps the design engineer of complex products to apply the eco-design principles without a trade-off on economic issues. The paper explains how the framework takes into account the product hierarchy and supports changes to the product design. Furthermore the paper presents an example of how the basics of the methodology are applied to a small household item.

Influences of KBE on the aircraft brake industry

A general review has been conducted to describe the situation of the aircraft wheel and brake industry and to describe possible applications of knowledge based engineering (KBE). The latest books and publications available to the authors have been reviewed during the survey to identify the latest thinking on the topic. The paper investigates tools to increase productivity in general, explains the way a KBE tool works, and describes possible KBE applications in the wheel and brake industry as design tools and as diagnostic tools. The relationship of KBE to existing IT systems is considered and put into the context of restructuring process. A case study describes the formulation of rules and the code that can be used with the ICAD software. Possible pitfalls are described. An outlook into future trends is included.

A review of reliability prediction

A general review has been conducted to emphasize the increasing concern with reliability in the engineering industry. The latest books and publications available to the authors have been reviewed during the survey to identify the latest thinking on the topic. Emphasizes the prediction of reliability and its use for further reliability analysis methods. Describes and briefly explains modern methods and tools for reliability prediction, to give an overview to engineers and managers interested in the subject. Includes a small case study of a subsystem of an aircraft system as example of an application of the subject. Includes in the reference section the books and papers used during the review and references for further reading into the subject.

Definition of generic relationships between design and manufacturing information for generative process planning

Abstract This paper defines the generic relationships between design and manufacturing information for generative computer automated process planning (CAPP). The relationships provide a unified format that is able to represent both the geometry, topology and technical requirements of a component and the machining operations to eliminate the complex definition and programming of logic and rules demanded by current generative process planning systems. This will reduce the efforts in developing complicated knowledge bases, applying sophisticated search algorithms and managing empirical knowledge, and therefore result in a simple software with highly automated process planning functions.

Computer assisted machine tool part-program optimization

Abstract Since numerically controlled machine tools are a complex technology in comparison to their conventional counterparts, the initial investment and maintenance costs are very high. Thus, it is necessary to make certain that the power and capabilities of these machine tools are exploited properly. This problem is especially acute when dealing with complex machine tools such as four and five axis lathes. The approach to adapting higher system utilization calls for the optimization of various factors. If the problem is to be optimized thoroughly, all these factors should be incorporated into a single objective, and then optimization carried out. The problem is therefore a complex one. Therefore, the objective of this paper is to identify particular areas where NC program optimization could best be applied and is most required. The paper reports on work carried out by the authors which introduces two important techniques for NC program optimization: dynamic optimization and verification systems using solid objects. An example is shown for a four axis NC lathe, which demonstrates a significant reduction of cycle time.

Rapid engineering of natural shaped objects with field data capture

In this work, a system is introduced to rapidly engineer natural shaped objects by means of a passive optical three-dimensional digitizer that uses little operator intervention to scan whole bodies. The scanning process is based on the principle of photogrammetry, in which objects are observed from two or more viewpoints and depth information is calculated with the help of triangulation. One of the main objectives is the flexibility of the scanner to allow its use in a variety of circumstances, for example in remote locations. This leads to the division of the actual scanning part from the data processing part, which makes the use of the scanner possible almost anywhere. The main focus is on the retrieval of accurate two-dimensional information from images taken with a standard digital camera, which can then be used in commercially available photogrammetry software for three-dimensional calculations. A system is developed in which the object is covered with a reference system that allows the recognition of individual reference marks and their correlation between pictures. The scanning of a foot for possible orthopaedic applications illustrates the use of the system. The subsequent cloud of points in the shape of the object allows further processing, such as rapid prototyping. This makes the scanner an ideal tool for modern manufacturing methodologies such as mass customization, in which customers can be supplied with a tailor-made version of a particular product, at the same costs as the mass produced version.

Case-Based Prosthetic Socket Design

A number of design methodologists have developed potentially useful models of design, but few of these models have addressed the full complexity of the design of a real engineering artefact. A joint research programme undertaken at Coventry University and the University of the West of England, Bristol, has identified case-based reasoning as a useful technique for representing engineering design information. A prototype design system has been developed (Vinney et al, 1999a; Vinney et al, 1999b) which operates in the domain of simple mechanical devices. The COnceptual Design ASsistant (CODAS) is capable of generating new design solutions with a controlled degree of novelty. Case-Based Reasoning (CBR) technology was used to store and retrieve past design solutions which were defined in terms of a symbolic representation language. This paper provides a summary of the results from the initial research and development work carried out in the field of mechanical device design and then considers the application of this technique to a complex design problem, that of prosthetic socket design.

The Case for a Case-based Design Assistant

A joint research programme currently being undertaken at Coventry University and the University of the West of England, Bristol, is concerned with developing a useful tool, for the novice or expert designer, which directly supports the conceptual design generation process in the field of mechanical device design. The COnceptual Design ASsistant (CODAS) achieves this by utilising knowledge of past successful solutions and then generating new devices, which can be either novel or routine, that are functionally capable of satisfying the stated device requirements. Case Based Reasoning (CBR) technology is used to store and retrieve past design solutions which are defined in terms of a symbolic representation language. The underlying design model is function based and employs a divergent function to form mapping technique to produce physical embodiments of the proposed functional solutions. The technique has been developed in the field of mechanical device design and is now being developed for use in the prosthetic design field.