The work presented in this thesis is an investigation into vehicle bodyshell structural joints, with the aim of improving their stiffness. The bodyshell joint is defined to be an area or sub-structure containing the intersection of beam-type members, the behaviour of which may be defined by a matrix determined experimentally or analytically by using the finite element method. An actual bodyshell was tested on a suitably designed rig and the primary displacement modes affecting the steady state and vibration response of a bodyshell were identified and the relevant stiffness measured by using a special transducer. The joint rotational displacements were measured in these modes and the relative importance of the joints obtained. The joints were then modified by the addition of stiffening plates and the effect on the various stiffnesses noted. To assist the analyst, a similar study was performed on the effectiveness of the panels, such as roof, floor and rear quarter. A finite element beam model was established for the bodyshell and modified until a good approximation was achieved with respect to the experiments. Some practical modification of three selected joints cut from the bodyshell was done in order to improve their stiffness. A theoretical study of the influence of spot welding size and spacing on the stiffness of two plates was made. A finite element model of an actual body joint was established and the effect on stiffness of various modifications was observed.

No description available.

No description available.

The crosswind sensitivity of a car is described as the sensitivity of a driver-vehicle system to vehicle movements provoked by wind influences. Research has shown that it is a contributory factor in accidents and that it is adversely affected by certain body shapes and by reductions in weight. Future legislation calling for a reduction in the amount of Carbon Dioxide produced by cars may well lead to this reduction in weight. Tests have been carried out on llth scale car models to compare the different results produced by static and dynamic tests. Although static tests are easier to perform, dynamic tests, in which the model is propelled across the wind tunnel, offer the advantage of an improved simulation of the skewed profile that the vehicle encounters at full scale. In these experiments a number of different skew profiles, turbulence profiles and model configurations including estates, hatchbacks and saloons, were tested at Reynolds numbers above 4x10⁵. The results showed that data from the more simple static tests were generally more conservative than those from the dynamic tests in a skewed profile up to approximately 30° of yaw. However, the static tests were unable to predict the peak yawing moment that occurs as a result of the transient flow over the model as it enters the gust. The dynamic tests also indicated oscillations in the flow over the rear end of the models in the hatchbacks with backlight angles of 22° and 36°, although less so in the latter. Other results suggested that there was an improved correlation between lift coefficients from different skew profiles, if the mean local velocity integrated over the height of the model was used to non-dimensionalise the data. Quality Function Deployment is not an appropriate framework to be used in the development of a complete vehicle but would prove useful if applied to the issue of crosswind sensitivity as a sub-component.

An improved understanding of the aerodynamics of high-speed ground vehicles can lead to significant reductions in the energy consumption required for propulsion, an increase of vehicle cruising speed, and an increase in the safety and comfort of passengers. To contribute to these goals, this thesis employs theoretical and experimental techniques to investigate the air flow around a proposed geometry for a high-speed electromagnetic suspension (EMS) train. Train motion at normal cruising speed in still air and in crosswind conditions are studied, considering aerodynamic forces and moments, the wake in the lee side of the train and the turbulent boundary layer development. The theoretical prediction work may be conveniently divided into two parts, for inviscid flow, and with viscous effects included. In the first, a numerical technique called the panel method has been applied to the representation of the body shape and the prediction of the potential flow and pressure distribution. Two computer programmes have been written, one for a single vehicle in the presence of the ground at different yaw angles, and the second for application to two body problems, e.g. a train passing a railway station or a train passing the central part of another train. Both programmes have been developed in fully three-dimensional form, but are currently based purely on the source distribution method. This limits the applicability of the method, in particular to small angles of yaw, but useful results are still obtainable. In the second part of the theoretical prediction work, two methods based on the momentum integral equations for three-dimensional boundary layer flow have been developed for use with the aforementioned potential flow analysis; these predict the development of the three-dimensional turbulent boundary layer (i) on the central section (for the analysis of crosswind conditions) and (ii) on the nose of the train. The primary interest of the experimental programme was to provide qualitative and quantitative results for comparison with the theoretical predictions as well as to give insight into the flow behaviour around the train. The experimental tests also provided the first results for the influence of both stationary and moving ground planes on the EMS train. Extensive wind tunnel tests were performed on four purpose-made models of the high-speed train to measure aerodynamic forces, moments and pressures to establish ground effect characteristics. The experimental results demonstrated the importance of ground clearance. Flow visualisation showed that the wake vortices were both stronger and larger in the presence of a ground. At small yaw angles ground clearance had little effect, but as yaw increased, larger ground clearance led for example to substantial increase in lift and side force coefficients. The wind tunnel tests also identified the differences between a moving and a fixed ground plane. The measured data showed that the type of ground simulation was significant only in the separated region. A comparison of the results predicted using potential flow theory for an EMS train model and the corresponding results from wind tunnel tests indicated good agreement in regions where the flow is attached. For small yaw angles, not more than 15°, predicted pressure distributions reproduced measured behaviour. For greater angles, the shed vorticity (associated with flow separation) has a strong effect on the surface pressure field and this would have to be introduced into the panel method to improve prediction. The turbulent boundary layer calculations for the train in a crosswind condition showed that the momentum thickness along the crosswind surface distance co-ordinate increased slowly at the beginning of the development of the boundary layer but then increased sharply at the side top roof on the lee side. The sharp increase is believed to indicate a tendency for flow separation as the solution procedure exhibits signs of failure in this region. Suggestions are made in the thesis for ways of improving both this and other aspects of the theoretical approach.

Thesis advisor: John Sallis / This dissertation gathers four studies on related topics in the phenomenological tradition and Martin Heidegger's philosophy in particular. Methodologically, it addresses the question as to how a reading of a philosophical text can offer access to the phenomena relevant for philosophy. Beginning with a reading of one his latest lectures on the end of philosophy and the the potential of phenomenology (The End of Philosophy and the Task of Thinking), the first chapter questions Heidegger's dismissal of the notion of ground in this lecture, arguing that an innovative reading of a passage from Contributions to Philosophy can address a problem left unresolved in the lecutre. Instead of reducing it to its alleged function in metaphysics, I propose to explore the semantic and descriptive potential of `ground' and related notions outside of the ontological and metaphysical discourse. The second chapter inquires about the particular position of On the Origin of the Work of Art in the context of Heidegger's theory of truth. In contrast to an interpretation highlighting the function of art in the so-called history of Being, the artwork essay is shown to display a specific form of transcendental argument aiming to disclose the `clearing' as the condition of possibility of phenomena. Particular attention is paid to Heidegger's discussion of untruth as concealment because the distinction between a denial (Versagen) and a restraint (Verstellen) of truth elaborates an important difference in discussing phenomena of negativity. The third chapter explores the notion of `earth.' The attempt is made to distinguish four phenomenal traits specific to earth by not only relying on Heidegger's discussion and the examples he gives in On the Origin of the Work of Art but by also connecting these to discourses on earth both in one of Husserl's later manuscripts (Foundational Investigations of the Phenomenological Origin of the Spatiality of Nature) and the philosophy of nature in Hegel's Phenomenology of Spirit. The discussion is oriented by an interpretation of two sculptures by Andy Goldsworthy; I reflect both on their methodological role for describing phenomena associated with earth and on the status of Heidegger's own examples. The chapter aims in particular to establish an explanatory priority of phenomene associated with earth over the lived body, showing that experiences featuring the phenomenal trat sof earth are irreducible to eminenty sensible experiences as experiences for my bodily being. The fourth chapter takes its departure from the German word Erklüftung that Heidegger mentions in Contributions of Philosophy. In discussing its particular position in Heidegger's discourse on both projection (Entwurf) and ground (Grund) in Being and Time, Contributions to Philosophy, The Origin of the Work of Art and Art and Space, I show why Erklüftung, although it can be established as the description of a specific phenomenon by referring to other occurrences of the word (such as in Goethe's writings on geology), I maintain that it is not apt for the purpose to which Heidegger submits the word. The failure of Erklüftung thus makes an important contributions to the understanding of Heidegger's discourse on ground. The conclusion offers a reading of the second half of Heidegger's last lecture course The Principle of Reason (Der Satz vom Grund) in order to situate the four studies vis-à-vis Heidegger's late comprehensive treatment of ground. His attempt to determine the meaning of ground and its equivalents in Latin ratio and Greek logos is distinguished from the regress to the beginning of the history of Being that the lecture develops. In contrast to this ontological way to determine ground, I defend the view that the semantic explorations and descriptions Heidegger gives offer more adequate access to the phenomena of ground. / Thesis (PhD) — Boston College, 2013. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Philosophy.

This thesis examines various control strategies aimed at optimising the steady-state operation of engine-transmission systems for heavy commercial vehicles in order to achieve minimum fuel consumption. The work includes three stages: i) the analysis and synthesis of the problems associated with the control of propulsion plants, ii) the mathematical optimisation of multi-variable systems and iii) the optimisation of an engine shunt-transmission system. The control of propulsion plants for heavy commercial vehicles is examined by reviewing the prime movers and transmissions in use or likely to be used in the near future. The parameters specially highlighted include the external controls and the alterations which can be made to improve component matching. The problem of optimising multi-variable systems is set out. The mathematical optimisation of multi-variable systems involves techniques for the maximization of a n-variable function specific to propulsion plants. The function maximized is not known analytically and can only be evaluated at discrete points. A large number of searching procedures are reviewed and developed to minimize the number of evaluations. The engine transmission system optimised comprises a diesel engine driving a hydro-mechanical transmission of the shunt type. The hydrostatic drive is made up of two variable-displacement units. The external controls are the fuel rack position and the two unit swash displacements. The characteristics of the system are investigated theoretically. Various optimisers, scheduled and on-line, are proposed and one has been fitted on a test rig and will be tested shortly.

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Bibliography: leaves 117-120.

Thesis (M. Sc.)(Geology)--University of Pretoria, 2005. / Includes summary. Includes bibliographical references. Available on the Internet via the World Wide Web.