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No description available.

There is considerable pressure on the U.K. clothing industry to remain competitive in the face of foreign competition. Market forces and the trend of decreasing contract sizes have produced perceived problems with current methods of production which, coupled with the inertia to radical change, justify research. Computer simulation is an established production management tool but its potential in clothing manufacture could not be inferred. Concentrating on progressive bundle systems as the dominant method of production, this research considers the capacity of simulation in this context. Factory-based studies identified factors affecting system performance which allowed a conceptual model with high face validity to be defined. The requirement to handle complex supervisory control strategies led to the identification of visual interactive simulation as an experimental route. A computerised model, with an appropriate user interface and reporting facilities, was developed in the ~Siman si@ulat~£~~Dguage __ This was supported by animated graphics which played a substantial role in the attainment of face validity. Replication was considered to be essential for sound estimates of system performance to be obtained from this stochastic model but, as interactive control works against replication, steps were taken to reduce compromise. Software development facilitated an experimental technique that employed interaction to develop a control strategy, which then became embedded in the model for replication. By providing control consistency between replications, a more reliable assessment of system sensitivity to stochastic variability was possible. Pilot runs and single factor analysis enabled the effect of controllable factors on system performance to be quantified. Supervisory control was found to have a major effect on system performance so that the need for consistency in interaction was amplified. Considering alternative experimental methods and the practical use of the model, application areas for simulation in the absence of real time data capture were identified and demonstrated. Each application offered significant advantage over currently available planning methods and the use of simulation was supported. Information from the model can be gained about the design and control of progressive bundle lines at the pre-production phase, and the output of performance indicators can be useful in assessing real production lines. The evidence presented by this research illustrates that animated simulation can provide insight that is otherwise unobtainable.

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Three aspects of ring rolling are investigated in this thesis, single stage closed-pass rolling, multi-stage rolling and radial-axial rolling. In Chapter Two, which deals with single stage closed-pass rolling, the rolling of a range of symmetrical and non-symmetrical profiles is investigated., The effects of feed rate, lubrication, small variations in the geometry of the roll and blank shape on profile filling are examined experimentally. The occurrence of defects and surface cracking and the stability of rolling when producing non-symmetrical profiles are examined. Rolling force and torque are predicted theoretically and comparisons with experimental results are made. In Chapter Three the production of a bicycle rim is investigated, following an enquiry from a cycle manufacturer. A multi-stage ring rolling operation is employed. The problems of profile filling, cracking and surface finish are solved. 'Means of providing stability to the rolling process and diameter control are developed and tested. The circumference is controlled to within 1 mm with radial thickness variations within 1% of the specified thickness. Various aluminium alloys and a magnesium alloy are used as test materiaLs. A theory for the dimensional limitations in relation to profile folding in the final stage is given. In Chapter Four a newly installed experimental axial rolling system is described. The system was designed and manufactured in the Department and it was provided with control and measuring equipment. Stability of the rolling process is examined theoretically and experimentally for axial and radial-axial ring rolling operations and the control system is examined. Rolling force and torque and power dissipation are predicted theoretically and compared with experimental results.

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No description available.

No description available.

Designers of consumer products are concerned with how their products will be perceived by consumers in the market place. The materials used in the manufacture of these products become the media by which the interface between the consumer and the designed product is perceived. Our perception towards these products will be strongly infleunced by the sensory interaction with the materials through both visual and non-visual means. Compared with the engineering properties of materials, sensory properties, perceived images, meanings and values of a material in the human-product interface, referred to as the 'material representation' are far from being systematically investigated. This is the background from which this research was initiated. The aim of this research is to explore the material representation in a holistic system, which is referred to as the visual narrative matrix. The matrix is created in an empirical way but based on a combination of theoretical and experimental research. Controlled experimental investigation is focused on the relationship between the material sensory properties (texture) and human subjective response via the sensation of touch. The theoretical analysis and the experimental findings contribute to the development of a new databse. the database will make it possible for designers, artists and engineers, through innovative treatment and application of existing and emerging materials, to be able to create artefacts more effectively matching human perceptual, sensory and emotional expectation. The experiemental findings and the visual narrative matrix are original. This thesis includes the research background, literature review, research methodology, the results from controlled experimental research, and the development of a matrix of material representation. By carrying out controlled experimental research on texture, it has been possible to identify a way in which people subjectively describe a material texture by touch (Dimension-Lexicons). Slight differences in these descriptive lexicons have been analysed in terms of gender, material surface finish, sensory conditions, and control groups etc. Further in-depth experimental research has revealed correlations between various subjective responses within texture perception dimensions. Understanding of these correlations will assist in the selection of an optimal material texture. A series of texture perception maps have been produced which directly display the nature of texture perception in terms of material categories and sensory modalities. In parallel, through experimental testing, the quantitative relationships between subjective response to texture and the objective physical parameters of materials have also been reported. This has provided important information about human sensory perception for the manufacturing and processing of materials. All of these experimental results have been integrated into the matrix of material representation.