Structure for a new section on rheology and material models in ASPECT

[naliboff]

I'm currently outlining a new section for the ASPECT manual to describe various rheological approximations and the material structure. Before diving in to far, it would be helpful to get the collective's thoughts on what should be included and organization.

Here is a first stab at an outline, which would start right after the Choosing a Formulation in ASPECT section in the manual:

1. Overview of Rheological Approximations in ASPECT Brief overview of what options there for linear/nonlinear rheology, segway to material model structure
2. Material Model Design differentiate Rheology versus EOS modules and subsections/submodules therein. These will be referred to in the next section.
3. Distinct Rheology Approximations (refer back 3.1 Constant Viscosity 3.2 Temperature-dependent viscosity 3.3 Diffusion Creep 3.4 Dislocation Creep 3.5 Peierls Creep 3.6 Simple Composite Viscous Creep 3.7 Diffusion and Dislocation Creep with Grain Size Evolution 3.8 Plasticity 3.9 Strain-dependent rheology 3.9 Linear Viscoelasticity 3.10 Viscoelastic plastic deformation 3.11 Future/In Progress Work 3.11.1 Iterative Composite Rheology 3.11.2 Coupling rheology to fluid pressure
4. Suggestions for adding new rheology modules and material models

[cedrict]

may be a section about invariants ? the two different types (moment and principal), which ones we use, their various formulations, etc ... ?

[naliboff]

may be a section about invariants ? the two different types (moment and principal), which ones we use, their various formulations, etc ... ?

@cedrict - Definitely, good call!

[bobmyhill]

Yes, I think this is good. To summarise my point from our meeting, I think In Progress Work is a good section, but maybe we should keep Future Work for the GitHub Projects page (https://github.com/geodynamics/aspect/projects).

I'd favour a brief paragraph at the end of eachIn Progress subsection summarising what still needs to be done / how users can use the in progress work (or even whether they should).

To address Anne's point, we should get in touch with the primary authors of potential In Progress stuff to ask them if they would be happy to write a short section / give permission for us to write it.

[tjhei]

In progress/ future work will likely be outdated quickly, so I agree with putting that into the issue tracker / board instead.

[gdmate]

Following on a conversation with a few others in the geodynamics community, there was a request to add a section regarding when/how the prefactor for viscous flow laws should be scaled and include a table of these values.

[bobmyhill]

@gdmate We can certainly do that. Do you just mean the scalings from various types of experiments? Would the paragraph from supplementary info S1.3 in Dannberg et al (2017; https://doi.org/10.1002/2017GC006944) be enough or would you like something extra?

[naliboff]

@bobmyhill - Sorry, accidentally posted that from my other GitHub account.

Do you just mean the scalings from various types of experiments? Would the paragraph from supplementary info S1.3 in Dannberg et al (2017; https://doi.org/10.1002/2017GC006944) be enough or would you like something extra?

Yes, exactly that, +/- a table with the correct values (converted or not) to use from various flow law experiments commonly used in the geodynamics literature.

[naliboff]

@bobmyhill @cedrict (and others) - I'm going to try and make headway on this sometime in the next few days. Any other suggestions to the outline in the first post (and subsequent discussion above) that I should take into account before getting started?