Browsing by Subject "Mechanical engineering"

Now showing 1 - 4 of 4
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    Case study: Custom-designed virtual experiment in fracture mechanics in Mechanical Engineering
    (2008-11-30) Hodgkinson-Williams, Cheryl
    This case study describes the development and use of a custom-designed virtual experiment in Mechanical Engineering which partially simulates the concept of metal fatigue to help student engage with a complex practical application. It then explores some of the enabling or constraining structures, policies and practices at a national, institutional and personal level that appear to have an impact on making such a simulation available as an open educational resource.
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    A concept model for a multi-fingered prosthetic hand
    (1997) Kotze, Johan; Nurick, Gerald N
    The various attempts by individuals to replace the hand has led to some ingenious and practical designs, but if compared to the real hand these designs are still light years behind. Till recently the most functional prostheses developed were body powered because of the simple, light weight designs. The designs for these hands have not changed must in the last few decades indicating that the design has reached its functional limit. This and the latest technology have initiated designers ' renewed interest in externally powered prostheses. Existing externally powered hands only have one degree of freedom which limits the function of hands considerably whereas practical multi-fingered hands would provide a new dimension to the functionality of prosthetic hands. For this project a concept model for a multi-fingered prosthetic hand was developed using Lego as design medium. The objective was to develop and test mechanisms as well as control strategies which can be used in a real prosthetic hand. A proper study of the human hand was done to determine its basic anatomy as well as its functioning. An extensive literature study on prosthetic and robotic hands was also done to evaluate existing designs and determine the level of existing technology. Special emphasis was laid on the anatomical design of the human hand which led to a model with a unique design. The model incorporates a tendon driven finger mechanism instead of the traditional linkage systems. This design provides an adaptable closing finger trajectory providing better grip. The model also provide actuation to all five fingers contrary to the three fingers of existing hands. This is achieved by a simple differential mechanism driving the last three fingers semi-independently with one actuator. The model also provides abduction of all fingers as well as opposition of the thumb improving the hands versatility. The hand is controlled using a personal computer and two interface boxes. Software was developed in Visual Basic to provide the user with a control analogue to that of a real myoelectric prosthesis.
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    Open Access
    Energy utilisation in South Africa.
    (1977) Bennett, Kevin Frank; Dutkiewicz, Ryszard Karol
    The purpose of this study is to provide the Department of Planning and the Environment with the following information: 1) The quantities and forms of input and useful energy used by different sectors of the South African economy. (The terms input energy and useful energy are defined in section 1.2 of this chapter). 2) The efficiency of conversion of input energy to useful energy. 3) Current and expected trends in energy utilization within individual sectors of the economy.The two year contract to carry out this study was awarded to the Energy Research Institute at the University of Cape Town. The work was undertaken by one engineer assisted by a graduate engineer, supported by secretarial staff and supervised by a professor of the Department of Mechanical Engineering.
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    Open Access
    Projectile penetration of thin aluminium plate
    (1978) Pearson, Giles Christopher; Dutkiewicz, R K
    The study of thin plate penetration has long been hampered by the lack of experimental data and that which has been reported is concerned mainly with displacement time records of the projectile and target responses to impact. In the present study two new techniques have been developed to monitor: the penetration process. The first records a specific particle deceleration in the projectile during penetration from which the forces of impact can be derived and the second records the growth of the projectile target contact area. Whereas data obtained from the first method can only describe the projectile's response to impact, it is possible by means of the second method to interrelate the projectile and target responses. The combination of these two techniques therefore provides a powerful tool by which thin plate impacts can be studied. To understand the nature of the experimental results which have been obtained, an empirical model of thin plate penetration has been developed. This analysis is based on the assumption that on impact, the target responds as a thin rigid plastic membrane and has been found to model the penetration process reasonably well for D/H ratios greater than 10.