A yield function to simulate earing in the deep drawing of aluminium

 

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dc.contributor.advisor Mitchell, Greg en_ZA
dc.contributor.author Thomas, Gary David en_ZA
dc.date.accessioned 2014-11-10T09:02:55Z
dc.date.available 2014-11-10T09:02:55Z
dc.date.issued 1996 en_ZA
dc.identifier.citation Thomas, G. 1996. A yield function to simulate earing in the deep drawing of aluminium. University of Cape Town. en_ZA
dc.identifier.uri http://hdl.handle.net/11427/9494
dc.description Bibliography: leaves 76-77. en_ZA
dc.description.abstract Deep drawing of metal sheeting is a commercially significant manufacturing process and as with all metal forming processes is subject to geometric defects. One defect of particular concern, termed earing, is characterised by an uneven edge to the drawn article. This work covers the implementation of a suitable constitutive model in a general purpose finite element code ABAQUS Version 5.4 to simulate this earing phenomenon in aluminium can body stock. Earing is caused by plastic anisotropy of the blank material and anisotropy induced during the drawing process. It is the result of crystallographic textures or preferred grain orientations that develop during the sheet rolling process. In polycrystalline materials it may be modelled via either crystallographic texture models or phenomenological yield surface models. Crystallographic models have the advantage over phenomenological ones in that they are able to describe both initial and evolving anisotropy. However, they are very demanding in terms of computational power and are reported to over predict the plastic strain ratios in anisotropic materials. A phenomenological yield surface model proposed by Karafillis and Boyce was consequently selected as a suitable constitutive model to investigate the earing phenomenon. This model can describe the elasto-plastic behaviour of both isotropic and anisotropic three dimensional polycrystalline materials. It is a pressure independent yield surface which is convex in stress space and assumes an associated flow rule. It was implemented in ABAQUS as a FORTRAN 77 User-Material Subroutine. An Euler Backward integration scheme was adopted and a consistent tangent modulus used. Four axisymmetric cupping operations were simulated: two with the model's parameters set to represent the aluminium alloy under consideration and two to investigate the effect of the yield surface on earing. For comparison purposes, a fifth case was run using the Hill (1948) anisotropic material model. en_ZA
dc.language.iso eng en_ZA
dc.subject.other Mechanical Engineering en_ZA
dc.title A yield function to simulate earing in the deep drawing of aluminium en_ZA
dc.type Master Thesis
uct.type.publication Research en_ZA
uct.type.resource Thesis en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Engineering and the Built Environment
dc.publisher.department Department of Mechanical Engineering en_ZA
dc.type.qualificationlevel Masters
dc.type.qualificationname MSc en_ZA
uct.type.filetype Text
uct.type.filetype Image
dc.identifier.apacitation Thomas, G. D. (1996). <i>A yield function to simulate earing in the deep drawing of aluminium</i>. (Thesis). University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Mechanical Engineering. Retrieved from http://hdl.handle.net/11427/9494 en_ZA
dc.identifier.chicagocitation Thomas, Gary David. <i>"A yield function to simulate earing in the deep drawing of aluminium."</i> Thesis., University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Mechanical Engineering, 1996. http://hdl.handle.net/11427/9494 en_ZA
dc.identifier.vancouvercitation Thomas GD. A yield function to simulate earing in the deep drawing of aluminium. [Thesis]. University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Mechanical Engineering, 1996 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/9494 en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Thomas, Gary David AB - Deep drawing of metal sheeting is a commercially significant manufacturing process and as with all metal forming processes is subject to geometric defects. One defect of particular concern, termed earing, is characterised by an uneven edge to the drawn article. This work covers the implementation of a suitable constitutive model in a general purpose finite element code ABAQUS Version 5.4 to simulate this earing phenomenon in aluminium can body stock. Earing is caused by plastic anisotropy of the blank material and anisotropy induced during the drawing process. It is the result of crystallographic textures or preferred grain orientations that develop during the sheet rolling process. In polycrystalline materials it may be modelled via either crystallographic texture models or phenomenological yield surface models. Crystallographic models have the advantage over phenomenological ones in that they are able to describe both initial and evolving anisotropy. However, they are very demanding in terms of computational power and are reported to over predict the plastic strain ratios in anisotropic materials. A phenomenological yield surface model proposed by Karafillis and Boyce was consequently selected as a suitable constitutive model to investigate the earing phenomenon. This model can describe the elasto-plastic behaviour of both isotropic and anisotropic three dimensional polycrystalline materials. It is a pressure independent yield surface which is convex in stress space and assumes an associated flow rule. It was implemented in ABAQUS as a FORTRAN 77 User-Material Subroutine. An Euler Backward integration scheme was adopted and a consistent tangent modulus used. Four axisymmetric cupping operations were simulated: two with the model's parameters set to represent the aluminium alloy under consideration and two to investigate the effect of the yield surface on earing. For comparison purposes, a fifth case was run using the Hill (1948) anisotropic material model. DA - 1996 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1996 T1 - A yield function to simulate earing in the deep drawing of aluminium TI - A yield function to simulate earing in the deep drawing of aluminium UR - http://hdl.handle.net/11427/9494 ER - en_ZA


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