Skip to main content

Stiffness Matrix

Problem in printing out the global stiffness matrix

Submitted by ashkan khalili on

Hi everyone,

I'm using UEL in ABAQUS. My model just has one 4-node element (defined in UEL) fixed in one end. When I'm running the UEL, it's working without any problm. But when I' trying to print out the global stiffness matrix I'm getting this error: "aborted with system error code 1073740940".

This is the way that I'm trying to print it out:

*STEP, NAME=STEP-1
*MATRIX GENERATE, STIFFNESS
*MATRIX OUTPUT, STIFFNESS
*END STEP

Would you please let me know what's the problem and how I can fix it?

Regards,

Print/ view the stiffness matrix in nastran

Submitted by bharathsf on
Choose a channel featured in the header of iMechanica

I have a model of a pressure vessel for which I need to see the stiffness matrix for selected elements. Is there any way of seeing the stiffness matrix only for selected elements in .f06 format of in . pch format in nastran

 Please help

Thanks in advance

Bharat 

*MATRIX GENERATE - Global Stiffness matrix

Submitted by salingerv on

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/boo…;

DOFs in Abaqus

Submitted by salingerv on

Hi,



I got a simple 2D problem (a rectangular shell, static general, CPS4R element), with 557 nodes, each of them have 2 DOFs (U1 and U2), according to the data file. But when I print out the ELEMENT STIFFNESS MATRIX, for each element it is a 12x12 matrix which means the rotational DOF about z axis is also taken into account. How can I omit this 3rd DOF? Can I?



Thank you.

how does ABAQUS design the cohesive element

Submitted by Hubert Chen on

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.