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http://hdl.handle.net/11375/10689
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DC Field | Value | Language |
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dc.contributor.advisor | Sowerby, R. | en_US |
dc.contributor.author | Karima, Mohamed Nassouh Medhat | en_US |
dc.date.accessioned | 2014-06-18T16:52:16Z | - |
dc.date.available | 2014-06-18T16:52:16Z | - |
dc.date.created | 2010-02-24 | en_US |
dc.date.issued | 1980-07 | en_US |
dc.identifier.other | opendissertations/572 | en_US |
dc.identifier.other | 2027 | en_US |
dc.identifier.other | 1169382 | en_US |
dc.identifier.uri | http://hdl.handle.net/11375/10689 | - |
dc.description.abstract | <p>This work is concerned with the wrinkling behaviour when deep drawing cylindrical cups from circular blanks. Wrinkling is a uniqueness problem, and the present work uses a bifurcation approach to predict its occurrence. The results are presented in terms of a critical ratio of blank diameter to thickness above which wrinkling commences, along with the number of waves into which the flange of the cup buckles.</p> <p>It is demonstrated that when the classical Prandtl-Reuss equations are incorporated into the bifurcation analysis, the theoretical predictions are at variance with the published experimental data.</p> <p>A number of ad-hoc modifications are made to the classical elastic-plastic model to make the predictions conform with the experimental results.</p> <p>A critical re-examination of both the flow and deformation theories of plasticity was carried out, leading to the proposal of a modified incremental theory. The modified constitutive equations is shown to reduce to an appropriate model for both elastic and rigid-plastic solids, as limiting cases. The consequence of the modified equations is non-coaxiality of the principal axes of stress and plastic strain increment, and this is supported by published experimental data. The proposed constitutive equations lead to a better prediction of the wrinkling behaviour vis a vis the other models discussed here-in.</p> <p>An experimental investigation of the wrinkling behaviour of a number of materials, drawn through a conical and a modified tractrix die, was undertaken. The study has resulted in proposals for certain material parameters as being beneficial for inhibiting wrinkling.</p> <p>A theoretical study of wrinkling when drawing through a conical die is also presented.</p> | en_US |
dc.subject | Mechanical Engineering | en_US |
dc.subject | Mechanical Engineering | en_US |
dc.title | A Bifurcation Study of Wrinkling in Deep Drawing | en_US |
dc.type | thesis | en_US |
dc.contributor.department | Mechanical Engineering | en_US |
dc.description.degree | Doctor of Philosophy (PhD) | en_US |
Appears in Collections: | Open Access Dissertations and Theses |
Files in This Item:
File | Size | Format | |
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fulltext.pdf | 5.66 MB | Adobe PDF | View/Open |
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