Error running element level calculix input file

1

Hey,

I am dealing with a problem.inp file containing 9840 nodes and 9600 elements within a specific domain. I’m utilizing a *frequency card with an orthotropic approach, specifically using *ELASTIC,TYPE=ENGINEERINGCONSTANTS to extract the element stiffness matrix.

I’ve developed a function that takes the problem.inp file as an argument and generates individual Calculix input files for each element, incorporating the frequency card and orthotropic material definition.

For testing purposes, I’m using E = 1, nu = 0.3, and G = 0.3846153846153846 (computed from E and nu).

The generated input file for element ID- 5905 is:

*Heading
Hash: A52bP1iH, Date: 17/01/2024, Unit system: MM_TON_S_C
*Node
1013, 3.20000000E-01, -9.20000000E-01,0.00000000E+00
4229, 3.20000000E-01, -9.00000000E-01,0.00000000E+00
7485, 3.40000000E-01, -9.20000000E-01,0.00000000E+00
7487, 3.40000000E-01, -9.00000000E-01,0.00000000E+00
*Element, Type=CPS4, Elset=Single_element
5905, 1013, 7485, 7487, 4229
*Material, Name=Steel
*Elastic,TYPE=ENGINEERINGCONSTANTS
1.0, 1.0, 0, 0.3, 0, 0, 0.3846153846153846, 0.3846153846153846
0.3846153846153846
*DENSITY
1.0
*Solid section, Elset=Single_element, Material=Steel
1.0
*Step
*Static
*Output, Frequency=1
*EL PRINT, Elset=Single_element
EVOL
*END STEP
*STEP
*FREQUENCY,SOLVER=MATRIXSTORAGE,STORAGE=YES
*END STEP

And the generated input file for element ID-5906 is:

*Heading
Hash: A52bP1iH, Date: 17/01/2024, Unit system: MM_TON_S_C
*Node
855, 3.60000000E-01, -9.20000000E-01,0.00000000E+00
6213, 3.60000000E-01, -9.00000000E-01,0.00000000E+00
7485, 3.40000000E-01, -9.20000000E-01,0.00000000E+00
7487, 3.40000000E-01, -9.00000000E-01,0.00000000E+00
*Element, Type=CPS4, Elset=Single_element
5906, 7485, 855, 6213, 7487
*Material, Name=Steel
*Elastic,TYPE=ENGINEERINGCONSTANTS
1.0, 1.0, 0, 0.3, 0, 0, 0.3846153846153846, 0.3846153846153846
0.3846153846153846
*DENSITY
1.0
*Solid section, Elset=Single_element, Material=Steel
1.0
*Step
*Static
*Output, Frequency=1
*EL PRINT, Elset=Single_element
EVOL
*END STEP
*STEP
*FREQUENCY,SOLVER=MATRIXSTORAGE,STORAGE=YES
*END STEP

I’m encountering an issue where the input file for element 5905 functions properly, generating all Calculix output files, whereas the input file for element 5906 does not.

I wanted to know the reason behind this issue.

Additionally, I’ve noticed that there are no problem running the 5906 input file when the G value is greater than 1. Are there any limitations associated with G>1 in Calculix?

I’m eagerly awaiting your response.

Thanks!!
Anoop

2

Abaqus documentation defines the stability conditions for orthotropic materials:

ortho stability
ortho stability987×468 22.6 KB

Abaqus may throw an error when they are invalidated. I doubt CalculiX has such preventive measures.

3

@Anoop_ng
I’m not sure if I understand your problem correctly, but both data sets makes similarly output in form and number of files when running with the official windows version of ccx_2.21 with both Pastix and Pardiso solvers