llnl / llnl/smith

Help users avoid accidentally specifying negative Poisson's ratio in Solid Mechanics module

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discretization documentation
Dominant language
C++
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Avg merge
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Merged PRs (30d)
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Description

see https://github.com/LLNL/serac/issues/586

Problem: right now, it's not obvious that some choices of {mu, K} result in a negative Poisson's ratio.

Some potential solutions:

1. Calculate Poisson's ratio from the user-specified elasticity parameters and ensure that its value satisfies `0 < nu <= 0.5`, or else issue a warning.

2. Change the `Solid` module interface to specify a different set of elasticity parameters (e.g. Young's modulus and Poisson's ratio) where Poisson's ratio appears explicitly.

3. Provide a few simple materials to choose from (e.g. `["copper": {"E" : 110, "nu": 0.33}, "aluminum": {"E": 68, "nu": 0.32}, ...]`, so users have the option to avoid manually inputting values.

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reading issue #586 and the Solid module interface, focusing on how users provide mu and K. The issue lists three possible directions, so work is not ready until one approach is selected; done should make negative Poisson's ratio choices explicit and prevent or warn about invalid values.

Written by the indexing model from the issue text.

Assessment

Tech stack
cpp
Domain
hpc
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

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