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Design and optimisation of a composite space frame chassis including experimental and computational analysis.

dc.contributor.advisorAdali, Sarp.
dc.contributor.advisorPadayachee, Jared.
dc.contributor.advisorVeale, Kirsty Lynn.
dc.contributor.authorNarsai, Mikhail.
dc.date.accessioned2020-04-10T12:49:45Z
dc.date.available2020-04-10T12:49:45Z
dc.date.created2017
dc.date.issued2017
dc.descriptionMasters Degree. University of KwaZulu-Natal, Durban.en_US
dc.description.abstractComposites are used in lightweight structural designs. In this dissertation, a robust carbon fibre reinforced polymer (CFRP) space frame chassis for a lightweight electric tricycle is produced. In large, most composite research is directed toward flat laminates rather than closed sections. This dissertation addresses the complexities of stresses at joints and buckling (local and global). The space frame design consists of two segments of iterations. The second and more important segment is based on optimisation using NX Nastran finite element analysis (FEA). The final design incorporates the use of steel sleeves to address stress concentrations at joins and local buckling. The design and execution of a new test method was developed to validate FEA results. The test method involves applying compressive stress on tubes fabricated using unidirectional (UD) fibre set at 35°, to induce compressive and shear stresses along the primary fibres. In this way, four major failure criteria were compared: Tsai-Wu, Hoffman, Hill and Maximum Strain. The Hoffman and Tsai-Wu criteria were shown to be accurate and conservative. The Hill criteria showed inaccuracy by having incorrectly high strength ratios, while the Maximum Strain criteria had the highest strength ratio, proving to be the least conservative and most inaccurate. This dissertation shows that certain failure criteria may be used confidently in applications such as filament winding and continuous pulComposites are used in lightweight structural designs. In this dissertation, a robust carbon fibre reinforced polymer (CFRP) space frame chassis for a lightweight electric tricycle is produced. In large, most composite research is directed toward flat laminates rather than closed sections. This dissertation addresses the complexities of stresses at joints and buckling (local and global). The space frame design consists of two segments of iterations. The second and more important segment is based on optimisation using NX Nastran finite element analysis (FEA). The final design incorporates the use of steel sleeves to address stress concentrations at joins and local buckling. The design and execution of a new test method was developed to validate FEA results. The test method involves applying compressive stress on tubes fabricated using unidirectional (UD) fibre set at 35°, to induce compressive and shear stresses along the primary fibres. In this way, four major failure criteria were compared: Tsai-Wu, Hoffman, Hill and Maximum Strain. The Hoffman and Tsai-Wu criteria were shown to be accurate and conservative. The Hill criteria showed inaccuracy by having incorrectly high strength ratios, while the Maximum Strain criteria had the highest strength ratio, proving to be the least conservative and most inaccurate. This dissertation shows that certain failure criteria may be used confidently in applications such as filament winding and continuous pultrusion methods, which are widely used in producing closed sections.trusion methods, which are widely used in producing closed sections.en_US
dc.identifier.urihttps://researchspace.ukzn.ac.za/handle/10413/17896
dc.language.isoenen_US
dc.subject.otherComposites.en_US
dc.subject.otherLightweight structural designs.en_US
dc.subject.otherCarbon fibre reinforced polymer.en_US
dc.subject.otherSpace frame design.en_US
dc.subject.otherPultrusion methods.en_US
dc.titleDesign and optimisation of a composite space frame chassis including experimental and computational analysis.en_US
dc.typeThesisen_US

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