Help with setting up Arrhenius rheology

Hello, I’m new to ASPECT and trying to recreate the results of an experiment done with StagYY. The experiment uses a simple Arrhenius viscosity law with a constant maximum value for clipping. I haven’t found anything built into ASPECT that allows for setting up an Arrenius viscosity and I’m having trouble figuring out how to set up viscosity clipping. Does anyone have any insight on how I can set this model up?

Hi Dylan,

welcome to the ASPECT community!
One solution would be to use the diffusion dislocation material model. It has both diffusion and dislocation creep, but if you set the dislocation viscosity prefactor to a really small value (something like 1.e-100, I am not quite sure if zero works), then the dislocation viscosity becomes so large that it essentially doesn’t influence your viscosity any more and what you have left is an Arrhenius law. This model also has a cut-off for min and max viscosity.

You can find a documentation of the equations used in the model here, under Parameter name: Model name, and then diffusion dislocation. Another option would be the visco plastic model, which allows you to select diffusion creep as your flow law, but this model would require setting the cohesion to a really large value so that no plasticity can occur.

Hope that helps!

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