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Plane Strain Extrusion – Slip-line Field Solution vs. FEM Solution. Nanshu Lu ES 246 Plasticity Project Jan. 11, 2006. Outline. Metal Forming – Extrusion Slip-line Field Solution Unsymmetrical Extrusion FEM Solution Conclusions. Metal Forming – Extrusion.
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Plane Strain Extrusion –Slip-line Field Solution vs. FEM Solution Nanshu Lu ES 246 Plasticity Project Jan. 11, 2006
Outline • Metal Forming – Extrusion • Slip-line Field Solution • Unsymmetrical Extrusion • FEM Solution • Conclusions
Metal Forming – Extrusion • Extrusion: Metal forming process whereby the workpiece is placed in a chamber with an opening and is forced to escape through the opening, usually being pushed out by a mandrel. Extrusion (a) and an assortment of extrudates (b) Metal Forming, Betzalel Avitzur, Lehigh University
F E Fan CAD C D x1 A x2 B G H Slip-line Field Solution Hill R. (1948)
Unsymmetrical Extrusion Green A.P. (1955) Eccentricity Fractional Reduction
Unsymmetrical Extrusion • Rough container walls • Smooth container walls
FEM Solution – Modeling Skills • Part: • Billet – 2D deformable shell • Ram – 2D analytical rigid body • Property • Material – steel • Elastic – 2000GPa, v=0.3 • Plastic – Yield Stress = 400MPa, perfectly plastic • Material Orientation – local coordinate system • Assembly • Billet – punch contact
FEM Solution – Modeling Skills • Step • “Move ram” after initial step • Maximum number of increments = 1000 • Initial Increment = 0.0001 • Minimum time increment = 1e-6 • Nonlinear geometry • Output request • History output – reaction force on the ram reference point • DOF monitor – monitor the horizontal displacement of the ram reference point
FEM Solution – Modeling Skills • Interaction • Frictionless surface-to-surface contact between billet and the ram at initial step • Load • Boundary Condition • Symmetric boundary condition • Displacement constraints • Imposed displacement to the ram (=0.05m)
FEM Solution – Modeling Skills • Mesh • Structured CPE4R elements • Global seed size 0.002m • Job • Monitor
FEM Solution – P~H Relation r=0.5,
FEM Solution – P~k Relation H=0.2m
Conclusion • Slip-line field method gives good solutions for metal-forming process • ABAQUS/CAE v6.5 is able to calculate perfectly-plastic material • Adaptive meshing is needed to simulate metal-forming process accurately • Thermal contact interaction should be included further
Acknowledgement • Joost Vlassak • Jennifer Furstenau • Xuanhe Zhao Thank You ^_^