Research Articles

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For information on accessing School of mechanical, industrial and aeronautical engineering Research Articles content please contact Salome Potgieter by email : salome.potgieter@wits.ac.za or Tel : 011 717 1961

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    Project Management Assessments (PMAs): an empirical study
    (Southern African Institute for Industrial Engineering, 2018) Siriram, Rajenlall
    The objectives of this research are to: a) compare project management assessments (PMAs) from four firms across four industry sectors (75 PMAs are evaluated using known statistical techniques); b) validate the results through an expert panel; c) apply Pearson’s correlation analysis to find links in the PMA constructs and see how these links relate to the overall project result; and d) identify areas for further research. Three hypotheses are tested, and reveal differences and similarities in project management practices. The results provide interesting opportunities for researchers and for project management practitioners. Finally, a discussion, the limitations of the study, and suggestions for further research are presented.
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    Effects of processing conditions on the mechanical and water absorption properties of resin transfer moulded kenaf fibre reinforced polyester composite laminates.
    (Elsevier, 2010-11) Rassmann, S.; Reid, R.G.; Paskaramoorthy, S.
    This paper focuses on the mechanical and water absorption properties of kenaf fibre reinforced polyester laminates manufactured by resin transfer moulding. Varying processing conditions were considered as alternatives to fibre treatments, thereby potentially avoiding additional cost and complexity in the manufacturing process. Laminates were produced by altering fibre moisture content, mould temperature and mould pressure following injection. Tensile, flexural, impact and water absorption tests were conducted. Processing conditions were found to have little effect on properties except for pressurisation which increased tensile and flexural strength and decreased water absorption at low fibre volume fractions. Examinations using a scanning electron microscope showed that all the laminates failed by fibre pull-out.
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    A novel method to measure residual stresses in unidirectional GFRP.
    (Elsevier, 2009-05) Reid, R.G.; Paskaramoorthy, R.
    A few methods are available for measuring the residual stresses that occur in the simplest of all possible composites structures - the unconstrained unidirectional laminate. None of them, however, are suitable for use on GFRP. A new method is presented whereby the stresses in a unidirectional GFRP laminate can be determined. The method relies on releasing the constraints between fibre and resin through an annealing process. The strain in the glass fibres is thus obtained, which allows the elastic stresses within the fibres and the resin to be determined. In this way, it is not necessary to take account of plasticity and viscous effects in the polymer in order to determine the stresses within the laminate. Results for unidirectional laminates initially manufactured to contain differing residual stresses are presented and discussed.
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    The effects of alkali-silane treatment on the tensile and flexural properties of short fibre non-woven kenaf reinforced polypropylene composites.
    (Elsevier, 2012-09) Asumani, O.M.L.; Reid, R.G.; Paskaramoorthy, R.
    Kenaf fibre reinforced polypropylene composites were manufactured by compression moulding. The kenaf fibre was considered in three forms; untreated, treated with sodium hydroxide solution and treated with sodium hydroxide solution followed by three-aminopropyltriethoxysilane. The effects of these chemical treatments on the tensile and flexural properties of the composites were investigated. Mechanical test results show that alkali treatment followed by three-aminopropyltriethoxysilane treatment (alkali-silane treatment) significantly improves the tensile and flexural properties of short fibre non-woven kenaf polypropylene composites. In particular, the specific tensile and flexural strengths of alkali-silane treated kenaf composites with 30% fibre mass fraction are, respectively, only 4% and 11% lower than those of composites made using glass fibre. Scanning electron microscopy examination shows that the improvements in the tensile and flexural properties resulting from alkali-silane treatment can be attributed to better bonding between the fibres and matrix.
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    The effect of residual stresses and wind configuration on the allowable pressure of thick-walled GFRP pipes with closed ends.
    (Springer, 2015) Carpenter, H.W.; Reid, R.G.; Paskaramoorthy, R.
    An investigation into the benefits of winding thick-walled glass fibre reinforced plastic (GFRP) pipes with two layers of different winding angles is presented. It is shown that layered pipes allow significantly greater internal pressures to be carried than can be achieved by pipes wound only at +/- 55 degrees if process induced residual stresses are ignored. It was found, also, that residual stresses severely reduce the allowable operating pressure of GFRP pipes. The reduction was most significant for the layered pipes, however, and this severely impacts on their utility. The most efficient pipe was nevertheless found to be a layered pipe, wound with a +/- 65 degrees/+/- 47 degrees combination. This pipe gives a 12 % improvement on the allowable pressure of the +/- 55 degrees pipe. This small performance benefit is achieved at the cost of significantly greater manufacturing complexity, and so the +/- 55 degrees pipe is probably still the most practical wind configuration.