Menu

Discussion Forum

New Discussion
Filter

Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.

Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

thermal stress

Posted Aug 2, 2012, 7:51 a.m. EDT Structural Mechanics Version 4.1 2 Replies

Pavan Kumar Penumakala
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam


Hello i am solving a thermal stress problem

with a viscoplastic materail model


i defined all the bc s

but i am getting the error for viscoplastic variables as

Undefined value found.
- Detail: Undefined value found in the stiffness matrix.
There are 1217 equations giving NaN/Inf in the matrix rows for the variable mod1.ex_v
at coordinates: (0,0), (0,0.02), (0,0.04), (0.0129312,0.0335295), (0.0258624,0.0270591), ...
There are 1217 equations giving NaN/Inf in the matrix rows for the variable mod1.exy_v
at coordinates: (0,0), (0,0.02), (0,0.04), (0.0129312,0.0335295), (0.0258624,0.0270591), ...
There are 1217 equations giving NaN/Inf in the matrix rows for the variable mod1.ey_v
at coordinates: (0,0), (0,0.02), (0,0.04), (0.0129312,0.0335295), (0.0258624,0.0270591), ...
There are 1217 equations giving NaN/Inf in the matrix rows for the variable mod1.ez_v
at coordinates: (0,0), (0,0.02), (0,0.04), (0.0129312,0.0335295), (0.0258624,0.0270591), ...
and similarly for the degrees of freedom, NaN/Inf in the matrix columns

i am attachinh the model..can anyone suggest on this please

Many thanks
Pavan

Attachments:

2 Replies Last Post Aug 6, 2012, 9:55 p.m. EDT
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Aug 2, 2012, 3:05 p.m. EDT
Hi

I cannot open your model, as I'm far away from my COMSOL WS, but typically I see those messages when I have nmissed a material data entry, when you change the state of the material (i.e. isotropic to anisotropic) then you MUST ALWAYS recheck your material data, as this will require other data entries and some might not be predefined

--
Good luck
Ivar
Hi I cannot open your model, as I'm far away from my COMSOL WS, but typically I see those messages when I have nmissed a material data entry, when you change the state of the material (i.e. isotropic to anisotropic) then you MUST ALWAYS recheck your material data, as this will require other data entries and some might not be predefined -- Good luck Ivar
Nagi Elabbasi Facebook Reality Labs
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Aug 6, 2012, 9:55 p.m. EDT
The problem is in the square root operation in Variable eeq. Some of its derivatives are undefined when all strain components are zero. You should add a small value (such as 1e-12) under the square root.

Nagi Elabbasi
Veryst Engineering
The problem is in the square root operation in Variable eeq. Some of its derivatives are undefined when all strain components are zero. You should add a small value (such as 1e-12) under the square root. Nagi Elabbasi Veryst Engineering

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.

Suggested Content