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Re: [Question #670047]: Determining macro parameters in uniaxial compression

 

Question #670047 on Yade changed:
https://answers.launchpad.net/yade/+question/670047

    Status: Open => Answered

Jan Stránský proposed the following answer:
Hello,

in the original script [1] (I guess?), stress-strain history is stored during the simulation using plot module [2].
Once having the stress-strain curve, the initial slope determines Young's modulus and its maximum/minimum value defines tensile / compressive strength.

The Poisson's ratio is somewhat more tricky, you would need to compute lateral displacement of particles and convert it to strain, then maybe by some averaging compute average lateral strain (I guess particles at the surface and those very close to the axis would corrupt the results and should not be considered, you would need to try).
Alternatively you can modify the test for uniaxial strain conditions (oedometric test), compute oedometric module and comparing it to the Young's modulus value you can determine Poisson's ratio. Or using triaxial stress determine the bulk modulus again compute Poisson's ratio comparing it to the value of Young's modulus.
A nice training would be to compare both (strain based and stiffness based) approaches :-)

> I don't know either which other macro parameters could be determined

you can get pretty much information, e.g. as mentioned tensile and compressive strength.
First you should know what and why you simulate and what results you want to extract. E.g. usually a simulation models a physical experiment and you compare simulation and experimental results.

cheers
Jan

[1] https://github.com/yade/trunk/blob/master/examples/concrete/uniax.py
[2] https://yade-dem.org/doc/user.html#tracking-variables

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