Conference Proceedings (Mechanical and Mechatronic Engineering)

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Browsing Conference Proceedings (Mechanical and Mechatronic Engineering) by browse.metadata.type "Article"

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    A concentrating solar power value proposition for South Africa
    (Energy Research Centre, University of Cape Town, 2013) Gauche, Paul; Von Backstrom, Theodore W.; Brent, Alan C.
    Concentrating solar power (CSP) offers the potential for a high degree of localization and an alternative strategy to meet electricity demand for South Africa in a future of uncertain conventional resources. The integrated resource plan (IRP) makes strides to introduce renewables to the electricity generation system by 2030, but we argue that the proposed energy mix is too reliant on resources that are not only unsustainable but also at risk in the short to medium term. Coal and other conventional resources may be more limited than originally anticipated, which if true, requires action to be taken soon. CSP is currently the only sustainable and dispatchable energy technology that could domestically supply a significant portion of South Africa’s electricity needs. A balanced mix of PV, wind and CSP can provide the energy supply needed in South Africa, but steps are required soon to take advantage of the localization potential and excellent sustainable energy resources.
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    Development of a model for predicting cycle time in hot stamping
    (Elsevier, 2018) Muvunzi, R.; Dimitrov, D. M.; Matope, S.; Harms, T. M.
    In manufacturing, reducing the cycle time results in lower production costs. The cycle time in a hot stamping process affects the quality characteristics (tensile strength) of formed parts. A faster cooling rate (˃27 K/s) of the blank guarantees the production of a part with the required microstructural properties (martensite). This compels researchers to continuously develop ways of increasing the manufacturing speed. On the other hand, it is important to predict the minimum cycle time for a given set of parameters which does not compromise the quality of formed parts. In this paper, a model for predicting the cycle time for a hot stamping process is presented. The lumped heat capacitance method is used in formulating the model since the temperature gradient across the blank and heat transfer within the plane of the blank are considered negligible. To validate the equation, a finite element simulation was conducted using Pam-Stamp software. The results show that the proposed model can be useful in further studies targeted towards cycle time reduction in hot sheet metal forming processes.
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    Using a filter-based SQP algorithm in a parallel environment
    (American Institute of Aeronautics and Astronautics, 2009-12) Venter, Gerhard; Vanderplaats, Garret N.
    A parallel, filter-based, sequential quadratic programming (SQP) algorithm is implemented and tested for typical general-purpose engineering applications. Constrained engineering test problems, including a finite element simulation, with up to 512 design variables are considered. The accuracy and serial performance of the filter-based algorithm are compared against that of a standard SQP algorithm. The parallel performance of the algorithm is evaluated, using up to 52 cores on a Linux Cluster. The results indicate that the filter-based algorithm competes favorably with a standard SQP algorithm in a serial environment. However, the filter-based algorithm exhibits much better parallel efficiency due to the lack of a one dimensional search.