Melting with non-linear rheology

Hello,

could someone point to what is needed to combine a visco-plastic material model with melting?
I guess an entirely new material model…but if I interpret the “calculation with melt transport” section in the manual correctly, it is not straightforward to have plastic failure in combination with melt transport.

Thanks
Lars

Hello Lars,
I am not an expert in the melt related parts of the code (@jbnaliboff or @jdannberg would know more), but yes as far as I know combining melt transport and visco-plastic rheologies is not a straightforward thing to do and an area of active research. Technically merging the viscosity calculation of the visco-plastic material model with one of the melt material models is the way to go about it, but you will probably encounter some issues on the way (e.g. solver convergence problems, incompatible equations for viscosity, potentially singularities in viscosity?). It would be an interesting experiment though. Maybe someone else has more insights.
Best,
Rene

Hi Lars,

this depends a bit on how realistic you want your model to be. We’ve made a model with melt transport and a simple stress-limiter rheology for a manuscript that is currently in review, you can find the manuscript here: https://arxiv.org/abs/1810.10105 (the model is described in Section 3.3)
and a description of how to reproduce the models here:
https://github.com/tjhei/paper-aspect-melt-paper-2-data

However, this does not include hydrofracturing, so there is no influence of the fluid pressure on the brittle failure mechanism. For a mid-ocean ridge system, this can be a good approximation, but it depends on the process you are interested in and may be more important for other applications. I’ve started to look at implementing hydrofracturing with @jbnaliboff, but this is technically challenging, and I am not sure when we will have this done. If you’re interested in the details, the method we want to implement is described in Keller et al., 2013 (https://academic.oup.com/gji/article/195/3/1406/2874184), and we can discuss this in more detail if you think this is what you need.

On the other hand, if you think that for your application you don’t need hydrofracturing, the model we use in the manuscript could ba a good starting point.

Cheers,
Juliane

…thanks for sharing the preprint and for supporting Open Science!

We are testing different melt emplacement hypotheses in mid-ocean ridge settings and a stress-limiting rheology already helps a lot. I will give it a try.

L.