The aim of the research described in this thesis is to assess the technical feasibility of pneumatic tyres for passenger cars which have no directional reinforcement in their carcasses. Conventional tyres are constructed from composites of twisted textile or steel cords in a rubber matrix, a process which is both labour intensive and costly. If it were possible to injection mould or cast tyre carcasses in a single operation, and if the performance of the resulting tyres matched that of modern radial ply tyres, then the implications for the tyre industry would be of major proportions. After reviewing the history of pneumatic tyres and summarising their principal attributes, the design of unreinforced or fabricless tyres is investigated and methods developed for defining their meridional profiles. Materials suitable for their carcasses and treads are then considered, prior to describing the manufacture of two series of tyres designed to have section height to width ratios, or aspect ratios, of 0.9 and 0.7 respectively. To facilitate experimental work, two sizes of tyres were employed: half scale models for which testing procQdures had been developed previously; and a size suitable for small saloon cars. The results obtained on a range of tyre properties are presented and analysed to give a number of empirical relationships between the properties and the design variables: carcass material Young's modulus, carcass wall thickness and the inflation pressure. For the important property of radial stiffness which affects other tyre characteristics, an improved method of analysis is developed to allow the structural and pneumatic components to be quantified. Using the relationships established experimentally, consideration is given to optimising the design of a fabricless tyre. It is concluded that to approach the performance of a conventional tyre, a design with a low aspect ratio is preferred but, to restrict growth with inflation'pressure, limited directional reinforcement must be included as a circumferential-belt beneath the tread. Nevertheless, the discussion concludes that there are fundamental reasons why even the optimised tyre would be unacceptable for use on modern passenger cars, although less demanding applications may be identified.

This thesis is concerned with the free vibration analysis of stiffened circular cylindrical and conical shells. The study was carried out with a view to improving the accuracy and efficieny of various modelling techniques for the prediction of the stiffened shells natural frequencies and mode shapes. A review of the existing literature covering various aspects of the shell vibrations problem and modelling techniques has been given at the beginning of each chapter with a critical appraisal of the assumptions made and results obtained. Initially the continuum energy approach was used for the analysis. The developed method allows for discrete consideration of stiffeners having arbitrary location and properties. Energy of bending in two planes and rotary inertia have been included in the analysis. Various types of stiffened shells with shear diaphragm ends condition were analysed using this method for the prediction of their natural frequencies. The predicted results have been compared with published experimental results. The finite element technique was also used for the prediction of natural frequencies and mode shapes of stiffened shells. Axisymmetric shell of revolution element, Facet shell element, semi-100f element and various types of beam elements, which are available within the PAFEC 75 suite of programs, were used for these studies. An efficient modelling technique has been introduced for ring stiffened cylindrical and conical shells by the use of the shell of revolution element. For improved accuracy of the predicted frequencies and a more economical model, shell symmetry was utilized for the free vibration analysis of unstiffened and stiffened shells. Half, quarter and one eighth models were studied by developing the appropriate boundary conditions and are discussed here. The free vibration characteristics of orthogonally stiffened cylindrical shells and an orthogonally stiffened cylindrical panel have been studied. An eight noded stiffened super shell element was developed for this study. This element was used for modelling various other types of stiffened shells and the predicted natural frequencies have been compared with known published experimental and theoretical results. Experimental verification of theoretical predictions of natural frequencies and mode shapes of an orthogonally stiffened cylindrical panel was carried out and is reported here.

No description available.

Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2008.

Thesis PlanB (M.S.)--University of Wisconsin--Stout, 2007. / Includes bibliographical references.

Thesis (M.A.)--Kent State University, 2009. / Title from PDF t.p. (viewed Mar. 31, 2010). Advisor: Jeffrey Ciesla. Keywords: Depression; driving impairment; driving; attention. Includes bibliographical references (p. 52-60).

Thesis (M.S.)--West Virginia University, 2000. / Title from document title page. Document formatted into pages; contains vii, 84 p. : ill. Includes abstract. Includes bibliographical references (p. 71-77).

Thesis (M.S.)--West Virginia University, 2000. / Title from document title page. Document formatted into pages; contains vii, 81 p. : ill. Includes abstract. Includes bibliographical references (p. 44-46).

Thesis (M.S.) in Forest Resources--University of Maine, 2008. / Includes vita. Includes bibliographical references (leaves 77-82).

Thesis PlanB (M.S.)--University of Wisconsin--Stout, 2006. / Includes bibliographical references.