# Meaning of domain strain rate

**URL:** <https://forum.itascainternational.com/t/meaning-of-domain-strain-rate/1298>\
**Category:** PFC\
**Created:** [January 17, 2024, 7:41am UTC](https://forum.itascainternational.com/t/meaning-of-domain-strain-rate/1298 "2024-01-17T07:41:11Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Prerna](https://avatars.discourse-cdn.com/v4/letter/p/eada6e/32.png) [@Prerna](https://forum.itascainternational.com/u/Prerna)\
**Post date:** [January 17, 2024, 7:41am UTC](https://forum.itascainternational.com/t/meaning-of-domain-strain-rate/1298/1 "2024-01-17T07:41:11Z")

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I am working on an example " Genesis and Testing of a Soft-Bonded Material" (file:///C:/Program%20Files/Itasca/PFC700/exe64/doc/pfc/pfcmodule/test3d/example\_applications/SoftBonded/softbonded.html?node3490). It uses strain rate of 0.1 and 1.0. What is the unit of strain rate in the example.  
Theoretically it has a unit of 1/s or %/s.  
Kindly specify what PFC uses its unit and exact meaning.

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**Author:** ![dblanksma](https://avatars.discourse-cdn.com/v4/letter/d/858c86/32.png) [@dblanksma](https://forum.itascainternational.com/u/dblanksma)\
**Post date:** [January 18, 2024, 3:47pm UTC](https://forum.itascainternational.com/t/meaning-of-domain-strain-rate/1298/2 "2024-01-18T15:47:34Z")

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Hello Prerna,

The units for strain rate are [m/m]/s or 1/s. The `strain_rate` value in this example simply sets the loading velocities for the direct tension and ucs tests.

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**Author:** ![Harshavardhan](https://avatars.discourse-cdn.com/v4/letter/h/9f8e36/32.png) [@Harshavardhan](https://forum.itascainternational.com/u/Harshavardhan)\
**Post date:** [August 4, 2024, 3:19am UTC](https://forum.itascainternational.com/t/meaning-of-domain-strain-rate/1298/3 "2024-08-04T03:19:42Z")

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Hello all,  
I need a small clarification on strain rate i.e.0.1, for a NX sample of height 108mm the calculated displacement rate is “0.1 \* 0.108m \* 60 = 0.648 m/min”. I mean 648 mm/min is very high displacement rate. Generally what is the suggested displacement rate for rock triaxial test.

Regards  
Harsha

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**Author:** ![apo16](https://avatars.discourse-cdn.com/v4/letter/a/b487fb/32.png) [@apo16](https://forum.itascainternational.com/u/apo16)\
**Post date:** [November 4, 2024, 7:51am UTC](https://forum.itascainternational.com/t/meaning-of-domain-strain-rate/1298/4 "2024-11-04T07:51:17Z")

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I am unable to post a separate topic, but I am also working on the example of “Genesis and Testing of a Soft-Bonded Material”. The goal is to obtain a strength value from the uniaxial test, and a few triaxial tests to calculate cohesion and friction angle to be used in slope stability models.  
When I run the simulation with my laboratory-obtained parameters I get strangely high strength value (around 500 MPa), while my triaxial are around 50 to 100 MPa.

Is there a difference between running a UCS with and without using domain distortion?  
If I run a simulation for ucs and triaxial shouldn’t Iget consecutively increasing data?  
Thank you for your input,  
Agata