• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1996.03b
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• pp.55-61
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• 1996

Finite element calculations are performed for crystalline solids subjected to plane strain tensile loading. Using Asaro's double slop model, shearband developments in single crystals are analyzed. The effect of various rate sensitivities and latent hardening parameters on microscopic plastic behavior was clarified. Moreover the deformation behavior of polycystals which have grain boundaries was compared to that of single crystals.

• Transactions of Materials Processing
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• v.11 no.8
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• pp.682-690
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• 2002

The formation of adiabatic shearband in tungsten heavy alloys(WHA) was studied in this investigation. Five prismatic specimens were loaded by high velocity impacts and treated as plane strain problems. To find out the effect of particle's volume ratio, specimens containing 81%, 93% and 97% volume percents of tungsten particles were used. Also the effects of particle's geometry and size on the formation of shearband were studied for 81% volume percent alloys by small size particle model, large size particle model and undulated particle models, and the results were discussed.be used to diagnose the causes of necking and fracture in industrial practice and to investigate whether these defects were caused by material property variation, changes in lubrication, or incorrect press settings. In non-axisymmetric deep drawing, three modes of forming regimes are found: draw, stretch, plane strain. The stretch mode for non-axisymmetric deep drawing could be defined when the major and minor strains are positive. The draw mode could be defined when the major strain is positive and minor strain is negative, and plane strain mode could be defined when the major strain is positive and minor strain is zero. Through experiments the draw mode was shown on the wall and flange are one of a drawn cup, while the plane strain and the stretch mode were on the punch head and the punch corner area respectively, We observed that the punch load of elliptical deep drawing was decreased according to increase of die corner radius and the thickness deformation of minor side was more large than major side.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.396-399
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• 2001

Development of adiabatic shear bands in thermoviscoplastic materials is analyzed via high resolution scheme. Presented here are our initial results, which are for one dimensional elasto-viscoplastic materials. As the mesh-sizes are getting small, the convergence result of plastic strain rate is obtained using elasto-viscoplastic materials. The further study cases will be reported at the presentation in the framework of the one and the two dimensional shearbanding, respectively. They will be compared with finite element solutions, and the advantage of the scheme will be discussed.