New to Esys

Asked by Christoph

Hi
I'm looking to model inelastic damage in tunnel faces using DEM and was wondering if Esys would be appropriate

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Dion Weatherley (d-weatherley) said :
#1

Hi Christoph,

Welcome to the ESyS-Particle forum on Launchpad!

The greatest strength of ESyS-Particle at present is the simulation of brittle deformation and fragmentation (not sure if that is what you mean by inelastic damage). I personally have interest in application of ESyS-Particle to mining engineering problems, particularly fragmentation during caving. Damage around excavations such as tunnels is closely related, as I'm sure you appreciate. On first impressions I would say ESyS-Particle is a good starting point for your research.

Without thinking too deeply about it, there will be a few technical challenges for such a study using ESyS-Particle. Firstly, you will need to design an initial particle packing that matches the tunnel geometry you are interested in. Our current LSMGenGeo library could be adapted I think. Secondly, you will need to consider boundary conditions. It might be prudent to consider periodic (or circular) boundaries along the tunnel axis to model a semi-infinite tunnel. That is no problem in ESyS-Particle. Thirdly, on other boundaries you will need to apply forces representative of the in-situ stresses acting on your tunnel however the boundary forces you need to apply may not be simple to calculate. This issue is common to any DEM code and may require some tuning or calibration to achieve the desired stresses. Static FEM analysis might help to constrain in-situ stress conditions. ESyS-Particle cannot help with that part...it is purely a DEM code! None of these issues are a major problem in my opinion.

I should also add a disclaimer here I guess: Although ESyS-Particle has been developed continuously for over 14 years, it's current capabilities reflect the applications it has previously been applied to. Consequently, it may require some programming in order to achieve your research goals. The release of ESyS-Particle via Launchpad is designed to foster a community of developers and users to expand the ESyS-Particle capabilities and help each other with their DEM research. The code is as much yours to mold to your needs as it is anyone else's. I encourage you to evaluate ESyS-Particle and will do my best to help where I can.

I hope this response is helpful and look forward to future collaboration.

Cheers,

Dion.

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Christoph (christoph-issi) said :
#2

Hi Dion

Thanks for your detailed reply!
After some investigation I've decided to attack the problem using a key block approach instead of a particle approach, which is better for modeling jointed rock with fractures and such. Do you know of any opensource code that does this?

Christoph

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Dion Weatherley (d-weatherley) said :
#3

Hi Christoph,

Sorry, I'm not familiar with the key block approach or software implementing that approach. You are quite correct to identify the need to model jointed rock for tunnel deformation though. DEM requires some computationally expensive modifications to handle that situation. Recently Itasca has developed an approach based upon DEM (specifically their PFC3D code) that models the elastic-brittle properties of jointed rock. The approach is called Synthetic Rock Mass (SRM) and there are a couple papers in the wild on the method. Perhaps SRM is worth keeping in mind if the key block approach doesn't pan out.

In any case, best wishes for your research. Feel free to drop a line whenever you like.

Cheers,

Dion.

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