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Penetration and convergence in contact; viscoplasticity

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Hi!

My ultimate goal is to simulate metal extrusion, specifically interested in the streamlines of the metal flow as the billet deforms in the die. I'm applying a prescribed velocity at the top surface of the billet, which starts as a cylinder sitting in the container. I am trying to use the Anand material model, available with the Viscoplasticity node, from the Nonlinear Structural Materials Module. All my models have been axisymmetric.
My first question is:

Is this feasible? I was hoping to apply remeshing as large deformation is occurring.

I'm using the Solid Mechanics module, using of course a constant temperature for the Anand model. I started with a transient model. However, I was having penetration of the billet into the die wall. Reading about contact, I implemented the penalty formulation found in the model "Contact Analysis of a Snap Hook Using a Penalty Formulation". To do this, I used a stationary study and a linear elastic material: aluminum billet (or cylinder) contacting a flat, thick plate (fixed constraint). I also implemented parametric sweep for solving. It worked up to a point, then it didn't converge. I plan to play around with the penalty factor.
I tried to use the Viscoplasticity material model (Anand model) to see if it worked at all, but I get an error about empty rows for the creep strain (solid.ece).

Any help, thoughts, tips, etc are greatly appreciated! I've been trying for so long!!

0 Replies Last Post 6 ago 2013, 15:13 GMT-4
COMSOL Moderator

Hello Sylvana Garcia

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