Learning Forum

[Rakshith Badarinath]

What is the difference between Equivalent Total strain and Max Principal strain (EPTO1 expression used in user-defined result)? When to use either of these and Is there a criteria to decide which one to use for analysis?  

[Erik Kostson]

See here:

 EPTO1 means total maximum principal strain (so epsilon_tot_11)

The equivalent total strain is as per the help manual:

' The equivalent total strain gives a total value of strain in any engineering body. The total strain components are calculated by addition of components of elastic, plastic, thermal, and creep strains and then equivalent total strain is calculated from total strain components. This result type is available in Mechanical only if at least one of the other three strain results is available for post processing'

 

Help manual:

Stress and Strain (ansys.com)

See below how to open the help link above:

/forum/forums/topic/how-to-access-the-ansys-online-help/

 

See also this discussion:

/forum/forums/topic/strain-von-mises-vs-principal-for-brittle-material/

All the best 

Erik

[Sampat Kumar]

Hi Rakshith,
As Erik correctly mentioned the difference between the equivalent strain and maximum principal strain, you can follow the attached link.
The sum of individual strain components (elastic, plastic, thermal, creep) for an engineering body can be expressed as the equivalent total strain.
Equivalent total mechanical strain (output using EPTO, EQV). The total equivalent strain is calculated based on the von Mises. EPTO1,2,3 means total maximum principal strain. 
Regards,
Sampat