Hi,
I have written a UMAT for isotropic linear hardening model for calculating tangent modulus matrix. Now I want to check that the obtained tangent matrix is correct or not, could you please help me by providing any suitable solved example?
Hello,
I just wanted to ask that the stiffness matrix in the plasticity region will be symmetric or not?
As we know the stiffness matrix or [C] is symmetric for elastic region.
Hi,
I am trying to implement material non-linearity by in-built isotropic hardening plasticity model without considering geometric non-linearity.
But if I am turning off the Nlgeom there is no change in slope so could you tell me how to implement material non-linearity without considering the...
Hi,
I have a problem related with .mtx file, which generated to store elemental stiffness value.
There are two questions:
1. In case of elemental matrix abaqus writes max. 4 value per line that's why the shape of matrix not looks clear.
I want to store this matrix in MATLAB or python but...
Thank you for the reply.
I have read the documentation and found the format for global matrix as First line
Row node number.
Degree of freedom number for row node.
Column node number.
Degree of freedom number for column node.
Matrix entry.
But for element stiffness matrix (as I attached in the...
Hi,
I am trying to export elemental stiffness matrix from Abaqus by adding the following lines in the input file
"*Element Matrix Output, Elset=Set-1, File Name=myMatrix, Frequency=1, Output File=User Defined,
Stiffness=Yes" for 4-noded linear quad element.
I got stiffness matrix but the size of...
Yes the boundary condition is non-zero and this is automatically propagating for gen step but not for the perturbation step.
If I will modify it will not be able to apply other displacement boundary in step-2 at the same node (that I wanted to do).
Now I just wanted to ask why BCs are not...
Yes, I have read this part from the documentation, but in my case it is not propagating from general static step to linear perturbation step.
It is propagating from one general static step to another general static step, please check the attached figure.
Why it is happening I am not...
Hello Sir,
In the restart analysis if both the steps are general static steps then there is propagation of displacement boundary condition is possible from step-1 to step-2.
But if we consider step-1 as gen. static step and step-2 as a perturbation step then the propagation of displacement...
Hello Sir,
"This way it’s possible. You can’t save the restart data in static linear perturbation steps (so you can’t restart from them) but you can read restart data in those steps (so you can restart to them)" this you mentioned in your reply dated 21/06/23. Could you please explain just for...
Hello Sir,
I have a doubt regarding the restart procedure. I have created step-1 where displacement is specified as 0.1 at a particular node (see the attached fig). Now I want to use restart analysis after completion of step-1 and in step-2 I have created another displacement BCs 0.00001(at the...
Thank you for your reply.
My doubt is related to the tangent modulus (9x9 matrix). Here in step-2, 9 restart files are used for calculating 9 columns.
But in step-1 if there is 10 increments then should be need to generate total 90 restart files (9 for each iteration)?
Because incremental load...
It means if step-1 is general static step with increment loading (suppose 10 increments are there) then in step-2 for each increment (10 times) we will have to read restart data?
If yes, so is there any way by which we can read all data simultaneously?
Because I want to calculate Macroscopic tangent modulus for Nonlinear materials using Perturbation Technique which is described in the paper "Comparative study of three techniques for the computation
of the macroscopic tangent moduli by periodic homogenization scheme".
Please check the attached...
Hello Everyone, I am trying to do a Restart Analysis with linear perturbation step in Abaqus for the plasticity problem (or to calculate tangent modulus for Elasto-plastic material). Can you tell me how to store calculated values for each iteration during restart analysis?
