calculate strain

Asked by Lukas Liebisch on 2020-07-09

Hi,

I want to calculate the strain field of a simulation. There is a tool ExtractStrain which didn't work for me (it just kept eating memory without producing any results), so I looked into the source code under Tools/ExtractStrain/DataExtractor.cpp and rewrote the function DataExtractor::StrainToTensorData in Python. I did a simple test and the algorithm calculating the deformation gradient tensor F seems to work fine.

The problem is that I don't understand how the algorithm works. Can anyone point me towards any literature explaining how you get from relative particle positions and relative displacements to the deformation gradient tensor? All books I could find that describe the deformation gradient tensor are about continuum mechanics and I don't know how to make the jump from continuum mechanics to the DEM.

Greetings,
Lukas

Question information

Language:
English Edit question
Status:
Solved
For:
ESyS-Particle Edit question
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Solved by:
Lukas Liebisch
Solved:
2020-07-11
Last query:
2020-07-11
Last reply:
Lukas Liebisch (lliebisch) said : #1

So I had a second look at DataExtractor.cpp and noticed a key phrase: best fit strain tensor. Using that I managed to find a paper explaining how this works ( doi.org/10.1016/j.ijsolstr.2005.07.016 for anyone curious).

Wasin Meesuay (kakkunno) said : #2

Dear Lukas,

Sorry to reopen this thread, but I have met a problem same with you, strainextract function didn't work and produced a blank result. Can you please guide me on this problem how to fix through those StrainToTensorData file?

Thank you for advance,
Wasin