Browsing by Author "Van Zyl, Erasmus Johannes"

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    Design and development of a morphing wing utilising flexible materials
    (Stellenbosch : Stellenbosch University., 2020-03) Van Zyl, Erasmus Johannes; Venter, Martin P.; Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering.
    ENGLISH ABSTRACT: Aircraft wings are required to operate in a multitude of different aerodynamic conditions. To compensate for these varying conditions, modern aircraft are equipped with devices that can alter the aerodynamic characteristics of the wings by altering their shape. Most of these devices use a joint or hinge mechanism and are relatively effective at controlling the airflow over the wings but also introduce losses in aerodynamic efficiency due to discontinuities that they create in the wing surface. These devices also create large point loads at the joints or hinges, resulting in an increased likelihood of failure occurring at these locations. An iterative design method is followed in the development of a low-cost and robust small to medium-sized Unmanned Aerial Vehicle (UAV) wing capable of changing its camber during operation. The overall design process was split into two sub-processes, namely designing a suitable wing base-structure and the design of a morphing mechanism to be used in combination with the base-structure. Multiple prototypes were developed and evaluated, which led to the selection of the best performing base-structure and morphing mechanism based on the overall stiffness of the prototype and the magnitude of possible camber-change. Further exploration was carried out on the selected morphing mechanism through the use of central-composite design (CCD) studies in conjunction with a Response Surface Methodology approach and One-Factor-At-a-Time (OFAT) analysis. Through this process, a mathematical relationship between the buildparameters of the morphing mechanism and its resulting bending output was established. The optimal build-parameter combination in the specified design range was obtained. Through the knowledge gathered, a topologically simple and low-cost morphing wing was developed and constructed. The designed wing was fully inflatable, offered bi-directional camber morphing capabilities and also had the shape-changing mechanism directly embedded into the base-structure, resulting in a wing that utilized no rigid components or complex joints between parts, making the design more resilient to small to medium impacts in comparison to traditional wing designs.
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    Die ontwikkeling van denkvaardighede : 'n didaktiese perspektief
    (Stellenbosch : Stellenbosch University, 1994) Van Zyl, Erasmus Johannes; Stellenbosch University. Faculty of . Dept. of .
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    Ondersoek na die verband tussen die leierskapstyl van die skoolhoof en die werkstevredenheid van onderwysers
    (Stellenbosch : Stellenbosch University, 1982) Van Zyl, Erasmus Johannes; Stellenbosch University. Faculty of . Dept. of .