UCS Test in PFC2D

Dear all,

On ucs test using PFC2D, side wall will be removed. How to derive the lateral strain from the test results?

Your answer will mean a lot to me, thank you in advance.

Hello Syani,
In this case I would use measurement spheres to find the lateral strain. You can review the description of the measurement sphere here - Measure — PFC 7.0 documentation.

Another possibility is to use “gage balls”. This concepts identifies certain balls in the assembly and keeps track of their relative displacements to measure strain. Gage balls are not a command in PFC, but have been implemented with FISH - Rock Testing — PFC 7.0 documentation (scroll to the bottom of the page, ss_gage.fis is the FISH function).

Thank you very much for your answer, Sir.
Can you give me an example how to use the command? I have tried with the following command, but no result comes out.
And, what should I do to bring up the history of stress vs strain? I have tried to replace the x-axis with a strain, but the results that appear are still steps.

Thank you

For your function defined as lateral_strain_gage. It loops through all the measurement spheres (circles in 2D) and writes the x-component of the strain rate tensor to “lateral_strain_gage”. You can create a history for this with the command:

fish history name <'str'> lateral_strain_gage

However, since you are using measurement sphere’s, you do not need to make a function to write to a history. Meaurement sphere’s have history logic built in. See - measure history command — FLAC3D 7.0 documentation

As for specifying the x-axis values, rather than the timestep, you can type in the histories name in the Vs field. Here is an example where the name is simply “1” and it becomes the x-axis of on the chart:

Thanks for the explanation. I have tried to use measure history but it doesn’t work. I tried measuring the lateral strain using a gauge like the one on Rock Testing — FLAC3D 7.0 documentation by replacing the top and bottom sides with right and left. Can I ask for a review, am I doing it right? I’m worried that I made the wrong script. Here is the script that I use.

Hello Syani,

Yes, we can review your code. Send your data files to PFCsupport@itascacg.com.

Okay, thank you for your help