I am trying to get eigen modeshapes of a 4-story 120 DOF building model in abaqus and haven't been able to get it. Either getting the eigen modeshapes directly or getting the stiffness and mass matrix would be fine. I have been facing the following problems:
First, I am not able to get .fil file in outputs. I am submitting the job as:
abaqus job=170_Dam0_1250_Matrices_old
My .inp file contains the following command as I have followed from other posts in this forum:
** STEP: Frequency
**
*Step, name=Frequency, nlgeom=NO, perturbation
*Frequency, eigensolver=Lanczos, sim, acoustic coupling=on, normalization=mass
, , 5000., , ,
**
** OUTPUT REQUESTS
**
*Restart, write, frequency=0
**
** FIELD OUTPUT: F-Output-2
**
*Output, field
*Node Output
U,
**
** HISTORY OUTPUT: H-Output-2
**
*Output, history
*Energy Output
ALLKE, ALLSE
*FILE FORMAT, ASCII
*NODE FILE
U
*ENDSTEP
What is wrong here?
My second problem is, I have been able to get global stiffness and mass matrices in the form of .mtx file. However, I haven't been able to post process it to get the symmetric K and M matrices. How do I get that form?
The .mtx file is of the following form:
-64,6, -64,6, 0.0
-63,1, -63,1, 0.0
-63,2, -63,2, 0.0
-63,3, -63,3, 0.0
-63,6, -63,6, 0.0
-62,6, -62,6, 0.0
-61,1, -61,1, 0.0
.....
My model has 36 unconstrained nodes with 6 DOFs and my ultimate goal is to get 216 length mode shape vector. Could you please help me with this?
