I’m trying to replicate a drained triaxial compression test in PFC using rigid walls. The experimental loading was applied at a constant displacement rate of 0.1 mm/min, and the specimen height is 100 mm. Since the strain rate is defined as rate = velocity/height, this gives:
rate=(0.1 mm/minute) /(100 mm) =1.667×10−5 s−1
I want to make sure this translation is appropriate for use in PFC. Would applying this strain rate (1.667e-5 s⁻¹) accurately reflect the experimental conditions, or are there additional considerations I should be aware of when implementing it in the simulation?
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I suggest that you use local damping with a damping coefficient of 0.7 to maintain quasistatic conditions during the test. If you do this, then your loading rate can be much larger than the loading rate in the physical test. This is explained in Section 5.4 Loading Rate in the material-modeling support memo that can be obtained from the link {Material-Modeling Support for PFC | US Minneapolis - Itasca Consulting Group, Inc.}
Is dt the timestep? And mostly the velocity we are providing is in m/s, right?
Also, I want to know how to determine the stresses in the shell elements?
I do not know to what document you refer to. Typically, the symbol dt is timestep. By default, in PFC, it has units of meters per second if you give properties in SI units. In FLAC3D, default units are meters per step. Getting stresses in shell elements can be visualized with Shell or Liner or Geogrid plot items as color contours. Also printed via structural shell list command and also via FISH. This is all explained properly in the manual in the Structural Elements section.