HI I am performing buckling analysis on composite shells in abaqus , I need to extract general stiffness matrix . How can I do that ?
Hi Aamir,
You can find the explanation and the link below;
"Modify the Input file and export the global stiffness matrix
In order to perform the static reduction procedure, the global stiffness matrix must be extracted from the ABAQUS finite element model. To do this, the Input file must be modified.
- This may be done by locating the Input file, which is usually located in the C:nTemp folder, and opening it with a standard text editor (.txt file extension).
- Once the Input file has been located and opened, use the text editor’s find utility (usually the key combination Ctrl+f), and search for the string of code shown directly below.
** STEP: Step-1
Directly above this line of code, some additional lines of code, with the command to export the stiffness matrix, must be added to the Input file. For ABAQUS version 6.11, the following code must be added.
*STEP, name=exportmatrix
*MATRIX GENERATE, STIFFNESS
*MATRIX OUTPUT, STIFFNESS, FORMAT=MATRIX INPUT
*END STEP
**
For versions of ABAQUS prior to 6.11, the code below must be added.
*STEP, name=exportmatrix
*MATRIX GENERATE, STIFFNESS
*END STEP
**
Once the Input file is modified as described above, the global stiffness matrix can be exported by running the modified Input file in ABAQUS, as described. Once the Job has completed, the global stiffness matrix should appear in ABAQUS’s Job folder (which is, again, usually the C:nTemp folder). If this procedure is performed on the Input file provided, then the resulting .mtx file should appear in the C:nTemp folder as the file example-1 STIF1.mtx.
Note that, the .mtx file format is ABAQUS’s matrix output format, and that this format can be read in a normal plain text editor (.txt file extension)."
http://www.eng.ox.ac.uk/stress/A%20Guide%20to%20Static%20Reduction.pdf
If you know the material properties of each layer and the stacking directions, you can refer to the following relations:
https://www.researchgate.net/publication/313792804_Stress_Development_Analysis_within_Composite_Laminate_for_different_Layup_Orientations
Conference Paper Stress Development Analysis within Composite Laminate for di...
Hi, I'm trying to obtain the stiffness matrix of a laminate shell in ABAQUS. As Oguzhan Yalcin has said, I write in the .input file the following commands before the **STEP line.
When I import the .inp into ABAQUS, appears a warning message saying the follow:
WARNING: The following keywords/parameters are not yet supported by the input file reader:
---------------------------------------------------------------------------------
*MATRIXGENERATE
*MATRIXOUTPUT
*PREPRINT
I add my .inp on order that someone could check it and tell me how I can fix this problem. Thanks
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