Thank you  for your reply. I know but I was wondering if it is possible to omit them manually.

 One more question, I figured that using *MATRIX GENERATE, one could get the global stiffness, mass or load matrix in a ".mtx" file. But I am wondering why I can't get the file after the run.

https://www.sharcnet.ca/Software/Abaqus610/Documentation/docs/v6.10/book...

 Here is the keywords:

*HEADING
… 

Hi,

Dear all,

I recently need calculate the stiffness matrix of the cohesive elements manually via mathematica. I used the finite element method to fulfill the assignment, but the result I got didn't match the stiffness matrix I extracted from the Abaqus. Neither did my supervisor.

knn, ktt and kss seem to be so obvious for the traction-seperation law, as also it measioned in Abaqus.  Could you please help me out by offering the way to find how the ABAQUS exactly design the cohesive elements or how ABAQUS calculate the stiffness matrix.

Any little help is so much appreciated. Thank you in advance.

Sincerely,

Chen

I would like to know how to write a stiffness matrix for a bar under torsional load. I would like to write a code in C++ to do this. I would like to know of any material regarding this.

Thanks in advance

With Br

Ashwin