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Coincidentally I was looking into simulating rope and knots for a side project, and I don’t know how to really research this other than googling, does someone i

Coincidentally I was looking into simulating rope and knots for a side project, and I don’t know how to really research this other than googling, does someone interested in these kinds of things know? I’d like to simulate friction and tensile strenghs, and other mechanical deformations (pulls, obviously).

AlotOfReading 4y ago
In general, the interesting properties of real ropes are not well-modeled by simulation. Dirt, abrasion, water, stress concentrations, and other real factors will dramatically impact the results you get out in the real world. That's why these things are experimentally verified and ropes used in safety-critical applications (are supposed to) have huge safety margins, regular monitoring, and ideally regular replacement. Use the manufacturer numbers for real ropes. But if you just want to simulate ropes, there's a few models out there from academics going "let's try and model this difficult system more accurately". Take a look at stuff like imc-der [0] and ridgerunner [1]. [0] https://github.com/QuantuMope/imc-der https://github.com/QuantuMope/imc-der [1] https://jasoncantarella.com/wordpress/software/ridgerunner/ https://jasoncantarella.com/wordpress/software/ridgerunner/
dekhn 4y ago
I've been curious about this too- there seems to be an underexplored area of physics around designing new knots with useful properties ("easy to untie under load") and it's not addressed by knot theory at al.
bg46z 4y ago
You could probably look at protein folding libraries like pymol. Although not exactly the same, it’s generally close enough to ropes and it has enough knobs where you should be able to run the simulations you want
- dekhn 4y ago
  Wouldn't really be helpful- first, pymol is a visualizer, not a folder. Also, proteins have properties very, very different from typical knots. That does raise an interesting question- can proteins spontaneously fold into knots? The answer is yes although I was discouraged when I originally asked this question in grad school.
- gilleain 4y ago
  Hmmm. PyMol is molecular viewer, which has a python scripting interface to various libraries ... but is not a folding library I would say. There is some research into the topology of DNA (especially circular DNA, like plasmids which is a knot) that considers things like writhe and twist. Not sure it would adapt too well to macroscopic systems though. There is also the excellent KnotPlot for actually drawing the knots. I bought a licence once on a whim, but rarely use it :)
GistNoesis 4y ago
Maybe you can look into (extended) position based dynamics https://positionbaseddynamics.readthedocs.io/en/latest/about.html https://positionbaseddynamics.readthedocs.io/en/latest/about... for ropes. If knots are what's interest you more, then maybe you can have a look at the self-collision avoidance of "Repulsive Curves" http://www.cs.cmu.edu/~kmcrane/Projects/RepulsiveCurves/ http://www.cs.cmu.edu/~kmcrane/Projects/RepulsiveCurves/

AlotOfReading 4y ago

In general, the interesting properties of real ropes are not well-modeled by simulation. Dirt, abrasion, water, stress concentrations, and other real factors will dramatically impact the results you get out in the real world. That's why these things are experimentally verified and ropes used in safety-critical applications (are supposed to) have huge safety margins, regular monitoring, and ideally regular replacement. Use the manufacturer numbers for real ropes. But if you just want to simulate ropes, there's a few models out there from academics going "let's try and model this difficult system more accurately". Take a look at stuff like imc-der [0] and ridgerunner [1]. [0] https://github.com/QuantuMope/imc-der https://github.com/QuantuMope/imc-der [1] https://jasoncantarella.com/wordpress/software/ridgerunner/ https://jasoncantarella.com/wordpress/software/ridgerunner/

dekhn 4y ago

I've been curious about this too- there seems to be an underexplored area of physics around designing new knots with useful properties ("easy to untie under load") and it's not addressed by knot theory at al.

bg46z 4y ago

You could probably look at protein folding libraries like pymol. Although not exactly the same, it’s generally close enough to ropes and it has enough knobs where you should be able to run the simulations you want

dekhn 4y ago
Wouldn't really be helpful- first, pymol is a visualizer, not a folder. Also, proteins have properties very, very different from typical knots. That does raise an interesting question- can proteins spontaneously fold into knots? The answer is yes although I was discouraged when I originally asked this question in grad school.
gilleain 4y ago
Hmmm. PyMol is molecular viewer, which has a python scripting interface to various libraries ... but is not a folding library I would say. There is some research into the topology of DNA (especially circular DNA, like plasmids which is a knot) that considers things like writhe and twist. Not sure it would adapt too well to macroscopic systems though. There is also the excellent KnotPlot for actually drawing the knots. I bought a licence once on a whim, but rarely use it :)

GistNoesis 4y ago

Maybe you can look into (extended) position based dynamics https://positionbaseddynamics.readthedocs.io/en/latest/about.html https://positionbaseddynamics.readthedocs.io/en/latest/about... for ropes. If knots are what's interest you more, then maybe you can have a look at the self-collision avoidance of "Repulsive Curves" http://www.cs.cmu.edu/~kmcrane/Projects/RepulsiveCurves/ http://www.cs.cmu.edu/~kmcrane/Projects/RepulsiveCurves/