Option to display other strain and stress measures
issueid=562 06-26-2012 05:07 PM
Option to display other strain and stress measures

Hi Steve,

This is a feature we discussed before but I wanted to bring it back to your attention.

It would be really nice if PostView could display a broad range of strain measures in addition to Lagrangian strain. For example, as per Holzapfel's notation:

- right stretch tensor, U
- left stretch tensor, v
- right Cauchy-Green tensor, C
- left Cauchy-Green tensor, b
- Euler-Almansi strain, e
- Hencky strain in material form, ln U
- Hencky strain in spatial form, ln v
- Biot strain in material form, U - I
- Biot strain in spatial form, v - I

These don't have to be evaluated every time that a file is loaded in PostView. There can be an option for the user to check which of those strains should be evaluated after a file has been loaded.

Similarly, in addition to the Cauchy stress, other measures of stress should be available, such as:

- first Piola-Kirchhoff stress, P
- second Piola-Kirchhoff stress, S
- Kirchhoff stress, tau

There are other stress measures which are not symmetric tensors (e.g., Biot, Mandel, Eshelby). Not sure yet that we would want to include these for now.

All of the strain measures can be evaluated within PostView. All of the stress measures can be similarly evaluated, as long as the plotfile includes the Cauchy stress.


Issue Details
Issue Number 562
Issue Type Feature
Project PostView
Category Analysis tools
Status Accepted
Priority 3
Suggested Version Unknown
Implemented Version (none)
Votes for this feature 1
Votes against this feature 0
Assigned Users maas
Tags (none)

06-27-2012 08:22 AM
I agree that this would be very useful (although perhaps not a high priority right now, given the other bugs and feature requests that we are working on).

I just want to mention that 1st P-K stress is also non-symmetric.



06-27-2012 09:14 AM
Right, thanks for the reminder ;)

05-08-2013 04:29 PM
I went ahead and implemented the following fields:

- right stretch tensor, U
- right Cauchy-Green tensor, C
- Hencky strain in material form, ln U

It turns out that Steve had already implemented
- Biot strain in material form, U - I


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