Implement persson's flat on flat electrostatic interaction as a potential

[sitangshugk95]

@sannant Was this ever implemented?

Also, if we ignore contact electrification, can the electrostatic potential simply be treated as an integral of the gap-dependent force (force between parallel-plat capacitors), which is cutoff at a distance when the electric field exceeds the dielectric strength? Then we can superimpose the two potentials (regular interaction potentials (eg; Exponential/PowerLaw) + electrostatic potentials) and treat the superimposed potential just like any other potential in the normal code.

[sannant]

I have to consent I cannot remember exactly what I ment with this issue. We worked a bit on electrostatic interactions with a student 2 years ago. Unfortunately we didn't implementing his work (see https://github.com/ContactEngineering/Adhesion/pull/27), and now the topic is completely out of my head. I am not sure I will be able to wrap that up.

If you are interested in these features maybe we can work on them together.

To your second, technical question yes it is technically possible to superpose two potentials but I don't think we have implemented it yet.

However, it would be straightforward.

I am not sure I understand your first question. Is it about physics or is it about implementation ? And doyou consider insulators with prescribed charges or conductors ?

As I said, I didn't work on this topic for two years now so that I think you understand this probably better than me.

[sitangshugk95]

Sorry I didn't make it clear - my question was about implementation - whether it would be possible to superimpose two potentials (which you're right, technically it should be possible). And yes, they can be considered as ideally perfectly insulating, for a good starting point.

I need to do some more thinking on it to make sure that I'm getting the correct potential, and then I can see if I can make a .py file similar to what you have made for the other generic potentials, and then possibly another that couples the effect of the two by superimposing them (which should just be algebraic addition, but may create some singularities).

[sannant]

Ok then maybe what you want to do is already implemented in this pull request.

https://github.com/ContactEngineering/Adhesion/pull/27/files

If that is the case I suggest that we both review and validate this code and then we can merge it.

[sitangshugk95]

Okay I will go through it in detail and try to figure it out (i.e. whether it gives the net force or just the electroadhesive force, and which interaction potential it chooses by default). I will get back to you if I have any questions. Thanks again.

[sannant]

Note: the code is two years old so I expect that you will get bugs because other functions have changed.

[sannant]

I can probably fix these bugs within the next days.