×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

USDFLD subroutine ABAQUS

USDFLD subroutine ABAQUS

USDFLD subroutine ABAQUS

(OP)
How does ABAQUS interpolate the values of a material property based on the variation of multiple field variables?

Hi fellow researchers, I would like to clear something in ABAQUS regarding the manner in which ABAQUS interpolates a material property that has been defined to vary according to a finite number of field variables using the user subroutine USDFLD. Let’s say I have a model where I am defining the Young’s modulus E varying according to 3 field variables F1, F2 and F3 as the following:

E poisson’s ration Field 1 Field 2 Field 3
50 GPa 0.3 1 0 0
30 GPa 0.3 0 1 0
20 GPa 0.3 0 0 1

In temperature dependence case, I understand the value of E at a particular intermediate temperature would have been considered by linear interpolation. However, in the above case how will ABAQUS consider the value of E at a point where F1=0.5, F2=0.3 and F3=0.2?

RE: USDFLD subroutine ABAQUS

Hi,

Your example is incorrect and interpolation can not be done in this case.

From Abaqus documentation (21.1.2 Material data definition, Interpolation of material data)

Quote:

When material properties depend on several variables, the variation of the properties with respect to the first variable must be given at fixed values of the other variables, in ascending values of the second variable, then of the third variable, and so on. The data must always be ordered so that the independent variables are given increasing values.

For three field variables with values in range from 0 to 2 we must define lines:

CODE

**
**
50 0 0 0
30 1 0 0
20 2 0 0
**
50 0 1 0
30 1 1 0
20 2 1 0
**
50 0 2 0
30 1 2 0
20 2 2 0
**------
50 0 0 1
30 1 0 1
20 2 0 1
**
50 0 1 1
30 1 1 1
20 2 1 1
**
50 0 2 1
30 1 2 1
20 2 2 1
**------
50 0 0 2
30 1 0 2
20 2 0 2
**
50 0 1 2
30 1 1 2
20 2 1 2
**
50 0 2 2
30 1 2 2
20 2 2 2
** 

In first column you can define any E value to describe dependencies you need.
Now interpolation is possible.

Regards,
Bartosz

VIM filetype plugin for Abaqus
https://github.com/gradzikb/vim-abaqus

RE: USDFLD subroutine ABAQUS

(OP)
Wow,
this was really helpful. Now it makes sense. Thank you so much. By the way, there is a link attachment redirecting me to github for a plugin. I have never used this plugin. Is the plugin useful? Thank you again.

Regards
Shufen

RE: USDFLD subroutine ABAQUS

Hi,

It you prefer to work directly with abaqus inputdecks in text editor the plugin make work easier.
However it is for VIM text editor so you have to know it.

Regards,
Bartosz

VIM filetype plugin for Abaqus
https://github.com/gradzikb/vim-abaqus

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources