A dented pipe fails either through being punctured or by fatigue damage accumulation due to internal pressure fluctuation. Increasing the wall thickness may prevent these failures but is impractical. As a pipe is punctured, transmission services must be cut off and repair processes have to be made immediately. However, when a dent depth is not large enough to puncture the pipe, the pipe can safely continue in service for a long time until a fatigue crack initiation occurs. Therefore, the fatigue life assessment has attracted much attention in the pipe industries for economic and safety reasons. The severe tensile residual stress concentration and the large plastic strain deformation in the dented region are the main causes of the pipe failure due to fatigue damage. Accurate calculation and prediction of the residual stress and variations resulting from internal pressure fluctuation can lead to safety assessments and prediction of the remaining life of the dented pipe. Due to the complex nature of the contact process, the deformed pipe geometry and the elastic-plasticity, analytical approaches are incapable of obtaining stress solutions. Therefore, FE modelling is employed in the present work. Experimental tests are employed to investigate the indenter force-dent depth behaviour which can be compared with the FE solutions to confirm and validate the FE models. The rigid perfect elastic-plastic limit load method and an energy-based method are also used to analytically calculate the limit load and the indenter force/deflection relationship of indented rings to predict damage. Two dimensional FE modelling is performed to calculate the contact and residual stress and strain distributions on the outer, inner surfaces and through the wall thickness. These FE solutions show that high stress concentrations occur in the indented region, which give the potential for fatigue damage. As the 2D FE modelling requires only limited resources, the indenter size and indentation position can be changed to analyse their effects on stress and strain distributions in the indented region. This forms the foundation of later 3D FE modelling. Stress sensitivity and the validation of shell models are investigated and confirmed through the 2D and 3D FE modelling and by comparing experimental test data with the FE solutions. Based on this work, the decision is made to use shell element modelling to perform the residual stress and stress range calculations in a 3D pipe. Semi-empirical formulations are developed to predict stress and stress range values if the residual dent depth, the pipe and indenter geometries, material property, internal pressure and pressure range are known. These FE solutions and semi-empirical formulae can be used to calculate the stress range and mean stress.

The difficulties that faced many manufacturing firms were attributed by Skinner (1969) to the inadequate attention given by top managers to the manufacturing function. He proposed a holistic framework of manufacturing strategy development that link manufacturing with corporate strategy. This work of Skinner is the first of three stages in the progression of thinking with respect to the strategic role of manufacturing as pointed out by Hum and Leow (1993). The other two stages being the demand of manufacturing to support and be consistent with corporate strategy (Wheelwright, 1978), and the present thinking that manufacturing can lead other functional areas in its contribution to the development of corporate strategy. This research is concerned with the current understanding of the strategic role of manufacturing which was provided by Wheelwright and Hayes (1985). They suggested that even though strategic manufacturing effectiveness is developed along a continuum, there are four identifiable stages that can indicate a firm's position. Furthermore, they suggested that strategic manufacturing effectiveness can be operationalised through the emphasis that firms place on manufacturing choices and decisions; there are factors that affect strategic manufacturing effectiveness; and the higher the level of strategic manufacturing effectiveness, the better the firm's performance. With respect to the factors affecting manufacturing effectiveness, Wheelwright and Hayes (1985) perceived five such dimensions. They are the attitude of top managers towards manufacturing, the involvement of manufacturing managers in setting the strategic direction of the firm, the emphasis on formulating manufacturing strategy, manufacturing proactiveness, and the co-ordination between manufacturing and other functions. The framework of Wheelwright and Hayes (1985) is a diagnostic tool that is used to appraise manufacturing's role within a firm. However, the relationships among its constituents have not been examined in detail before. This research develops a model that clearly identifies such dimensions and how they influence manufacturing effectiveness. Also, the notion that there are four identifiable stages is investigated. Moreover, mediating effects of the types of industry, the sizes of firms, and the types of production process on manufacturing effectiveness are also examined. The results from hypotheses testing indicated the significance of the attitude of top managers towards manufacturing and the involvement of manufacturing managers in setting the strategic direction of the firm as being the key factors that influence the process of acquiring strategic manufacturing effectiveness.

Automated assembly technology may be the key to sustaining manufacturing industry in more developed countries. Currently this comprises dedicated systems that can assemble single products at high volumes and flexible systems to assemble a wide variety of products in low volumes. However, competitive forces demand a compromise between the two and Reconfigurable Assembly Systems are an avenue for achieving high volume and high variety production. Although this technology is coming to the fore, there is a distinct lack of tools and methods that make the prospect attractive to key decision makers in organisations. Reconfigurable solutions, which may be profitable in the long term, are rejected in favour of short term solutions, which prove to be more expensive over time. The benefits of requirements engineering have been exploited in software engineering and this work demonstrates how these can be adapted to an assembly environment to form a new basis for communication between the system vendors, who supply assembly system solutions, and system users, who use them. Knowledge Engineering has become a key aspect in industry due to the challenges of retaining personnel and their knowledge within organisations. This is because employees take their knowledge of the organisation with them when they leave. The retention of this knowledge would help to maintain the continuity within organisations. This thesis reports on research that aims to provide a means to integrate these three aspects to form a basis for sustaining competitive manufacture in more developed countries. Moreover, Knowledge Based Requirements Specification for Reconfigurable Assembly Systems will provide a vital medium for promoting Reconfigurable Assembly Systems and encourage their implementation by providing a knowledge-based platform for the specification of Reconfigurable Assembly Systems.

Rapid prototyping (RP) provides a means of producing physical models directly from computer aided design (CAD) data. The aim of this research was to determine the most effective method of integrating RP into the design process. A review of the links between design and RP was undertaken. This revealed that RP is a technology which can benefit several key areas of engineering design. Many computer tools were identified which supported the designer's use of RP but most of these relied on using CAD geometry alone. Using this incomplete set of design information hindered the integration of RP into the design process. A hypothesis was formulated which stated that a feature-based product modelling methodology was needed to enable RP to become an integrated part of the design process. To demonstrate the validity of the methodology, it was embodied in a design support system (DSS) for rapid prototyping. The DSS requirements were determined through a survey of designers using RP, and a full specification for the system was defined. A demonstration version was implemented using a relational database coupled with a CAD system. The demonstration DSS enabled feature-based geometry and non-geometric information to be integrated within a single product model. An application program was developed which used the product model data to optimise the orientation of an RP model in order to meet the differing surface finish requirements for each feature in a component. This example use of the system illustrated the benefit of using a feature-based product model to optimise the designer's use of RP. Future work needed to improve the DSS to a state where it would be ready for development into a commercial package was identified. Finally, conclusions were drawn as to how all the objectives were met and summarising the original contribution to knowledge made by the research.

Several techniques are applicable to the modelling of production and inventory control systems. In this thesis discrete linear control theory is examined as a method of modelling multi-product, multi-level systems. These systems are categorised and a general discrete linear control model is used to determine system stability and to predict system responses to specific patterns of input information. The response of the system to random variability in input or other system variable is also shown to be predictable. A library of sub-system models is provided and the method is illustrated by examples and a case study. Alternative modelling techniques rely upon sequential simulation, either directly or in solving equations representing the system. The need to include forecasting, inventory and production decision-making procedures makes such models large and their sequential nature imposes the need for complete remodelling for each system modification and for each input pattern. Where random effects are modelled, protracted runs are necessary to achieve statistically acceptable results. In contrast, discrete linear control theory provides a nonsequential model, thereby alleviating these problems. Thus it is possible both to reduce computing expense and increase the range of systems susceptible to manual analysis. The method is limited by the restriction of linearity, but, in many practical situations this restriction poses no insuperable difficulty in the interpretation of results.

Electroplated zinc alloys can provide increased corrosion protection for automotive body panels compared with zinc coatings of similar thickness. As a result, their use is becoming widespread. In particular, outstanding results have been reported in the literature for the corrosion resistance of zinc-manganese, and the alloys are said to offer good paintability, weldability and formability. However, the production of zinc-manganese coatings is restricted by the instability of the sulphate-citrate bath from which the alloy is usually deposited. The solution deteriorates rapidly and precipitates appear in the bath. The aim of this research was to investigate both the process of alloy deposition from the sulphate-citrate bath and the solution instability. The electrodeposition of zinc-manganese was assessed in terms of the polarisation behaviour of the system, in order to determine the role of the bath components and the operating parameters in the deposition process. The coatings were analysed using scanning electron microscopy, and the efficiency of metal deposition was established. The sodium citrate complexant was not found to significantly move the deposition potentials of zinc and manganese together. Instead, its action as a buffer can be used to explain metal deposition and the polarisation behaviour of the system. The sodium citrate suppresses the hydrogen evolution reaction, such that manganese can be deposited from the electrolyte. The bath deterioration with time and the resulting precipitate were examined using a variety of chemical techniques including spectroscopic methods, namely ultraviolet and visible, atomic absorption and infrared. Bath discolouration and precipitation were found to be two separate phenomena. The precipitate was determined to be a citrate of known composition with a ratio of Mn2+ ions to Zn2+ ions of 2:1. The formation took several days, and it was precipitated once the solubility limit in the bath was exceeded. Solution discolouration resulted from reactions occurring after the oxidation of Mn2+ ions and could be delayed by the use of antioxidants.

Next generation manufacturing companies have to become highly responsive in order to succeed in an ever more rapidly changing global market. The ability to effectively develop and adapt their assembly facilities (systems) to changing requirements on demand plays a crucial role in achieving high responsiveness since the assembly process has to deal with the full inherent complexity of increasingly mass-customised products. This work was motivated by the current lack of a holistic assembly system design theory that would enable design environments to address the need for rapid system development and adaptation. The challenge is to create a common environment where domain experts can effectively collaborate while taking advantage of the best practices of their diverse domains. This thesis investigates how a domain ontology can help to overcome those challenges. The approach is taking advantage of the higher levels of standardisation inherent in the modular assembly system paradigm which is considered to be one of the fundamental enabling factors to achieve a high level of adaptation. A new ontology framework has been developed to support the design and adaptation of modular assembly systems (ONTOMAS). The ONTOMAS framework is based on engineering ontology principles structuring the domain using formalisms for aggregation, topology, taxonomies, and system theory principles. A number of design patterns have been identified and formalised to support key design decision-making tasks during the design of modular assembly systems. Furthermore, the function-behaviour-structure paradigm has been applied to capture the characteristics of modular assembly equipment at different levels of abstraction that reflect the specific needs of the engineering design process. The proposed ONTOMAS framework provides a sound foundation for computer based support tools to reduce the assembly system design effort and time while maintaining a high level of quality. An integrated design framework for the requirements driven specification of assembly processes and configuration of modular assembly system has been developed. The design approach applies the new formalisms of ONTOMAS to support the design decision-making activities. The developed ONTOMAS framework has been applied in several industrial and synthetic use cases to verify its applicability and appropriateness. Furthermore, the new ontology and design framework have been used as foundation for the development of a prototype collaborative design environment which allows different domain experts to participate in the design of modular assembly systems.

This thesis presents two computer packages to simulate the rotary forging process, by means of a mathematical model. The results are displayed in a graphical and numerical manner, showing the tool movement and the tool / workpiece interaction. The first package, PATH, is shown to be capable of simulating the motions of all known rotary forging systems. Its results show the rotary forging tool path throughout a chosen process. The motions of any rotary forging system can be programed by a simple set of instructions displayed on the screen, and the results displayed quickly and graphically. The widely used motions of rocking - die rotary forging machines were investigated. From these investigations, formulae were put forward, which were shown to be capable of predicting the tool motion of any rocking - die rotary forging situation. The second package, PROFS, presents a meshed representation of the tools and workpieces used in rotary forging systems. The rotary forging tool is represented as a conic wire frame mesh, on which no forces or loads are considered to act. The workpiece is represented as a cylinder constructed from a number of hexahedral elements. The elements are treated in either a non - constant volume or a constant volume manner. The non - constant volume model workpiece is one which is simply cut away by the action of the tool on it. This model is similar to a process of 'rotary cutting'. Using the model, a technique of investigation into the progression of the contact geometries created during a real rotary forging, was developed. It enabled the progression and size of the contact geometry to be followed from start to finish of the forging cycle. No consideration of the loads or forces occurring during the process was taken into account. The constant model workpiece requires that its volume remains fixed during the simulation. This is achieved by a radial expansion of the elements of the workpiece as it is being 'deformed' by the tool. Again no consideration of the loads or forces occurring in rotary forging was taken into account. Investigations, using the model, enabled the instantaneous contact geometries, contact areas, and displaced volumes of material to be predicted during two real rotary forging processes. Results revealed the potential of PROFS, to determine areas of workpiece instability in the early stages of forging, and reveal ares of insufficient die fill. The potential of data from the simulations, to control a rotary forging machine, is discussed, and is seen as the first step towards the design and manufacture of rotary forging parts and dies by a C.A.D. - C.A.M. route. Contact areas produced during the rotary forging process are essential for any calculations of the forces and stresses occurring in the die and workpiece. The possibility of PROFS to be used as a die / design tool and in pre production trials for new parts is discussed. A physical simulation of a non - constant volume model workpiece was carried out using a 'short lead milling' technique to cut away a solid workpiece. This revealed the instantaneous contact geometries and areas of the workpiece, which were shown to be accurately predicted by PROFS using the non - constant volume. The results confirmed the accuracy and validity of the simulated instantaneous geometries, allowing a large degree of confidence to be assumed in the accuracy of the package. A data base of radial, circumferential, and custom die profiles has been built up and incorporated into PROFS. From the data base a chosen profile can be used to generate a conic meshed representation of a rotary forging die. Investigations, using a die generated from a custom profile, revealed areas of possible workpiece instability. The two packages put forward in this thesis have been shown to be capable of simulating the motions and contact geometries of the rotary forging process, and confirmed using physical and real rotary forging comparisons.

The study reported on in this thesis was an empirical investigation into the implementation and use of, Statistical Process Control (SPC) techniques and tools in a product development environment. The data used originated from four different business units in the European flavour division of a large International company, belonging to the Flavour and Fragrance industry. The study highlights many of the problems related to the use of real data, and working with individuals throughout an organisation. The data distributions were positively skewed, and a comparison of the effectiveness of various methods for calculating the position of both the center line and the process control limits, on individual measurements control charts was made. The author was able to show empirically that SPC is a useful project management tool. Additionally, the author demonstrated that the use of either the median or trimmed mean approaches, were more effective in use when dealing with these types of skewed data distributions. Additionally, it was possible to define the relationship between the numbers of outside out-of-control signals and the numbers of run out-of-control signals. The study also provided some interesting insights into possible barriers to the transfer of the techniques, from the manufacturing floor into more traditional management areas. It also highlighted some areas for improvement in the product development laboratories of the company and potentially the industry.

Discrete event simulation is now a well established modelling and experimental technique for the analysis of manufacturing systems. Since it was first employed as a technique, much of the research and commercial developments in the field have been concerned with improving the considerable task of model specification in order to improve productivity and reduce the level of modelling and programming expertise required. The main areas of research have been the development of modelling structures to bring modularity in program development, incorporating such structures in simulation software systems which would alleviate some of the programming burden, and the use of automatic programming systems to develop interfaces that would raise the model specification to a higher level of abstraction. A more recent development in the field has been the advent of a new generation of software, often referred to as manufacturing simulators, which have incorporated extensive manufacturing system domain knowledge in the model specification interface. Many manufacturing simulators are now commercially available, but their development has not been based on any common standard. This is evident in the differences that exist between their interfaces, internal data representation methods and modelling capabilities. The lack of a standard makes it impossible to reuse any part of a model when a user finds it necessary to move from one simulator to another. In such cases, not only a new modelling language has to be learnt but also the complete model has to be developed again requiring considerable time and effort. The motivation for the research was the need for the development of a standard that is necessary to improve reusability of models and is the first step towards interchangability of such models. A standard framework for manufacturing simulators has been developed. It consists of a data model that is independent of any simulator, and a translation module for converting model specification data into the internal data representation of manufacturing simulators; the translators are application specific, but the methodology is common and illustrated for three popular simulators. The data model provides for a minimum common model data specification which is based on an extensive analysis of existing simulators. It uses dialogues for interface and the frame knowledge representation method for modular storage of data. The translation methodology uses production rules for data mapping.