D4TRIU WARNING

[Bruce Wayne]

Hello Feap Users,

I am trying to do FE2 analysis(Feap 8.6) on a block subjected to 1% of displacement on one side and fixed on the other side. I want to get stress -strain data of this block for all elements over some time steps.

I am getting a warning message "D4TRIU WARNING" solution is not solved.

I also have another doubt. Is there anyway to get stress and strain data over all time steps for all elements?
I tried TPLOT but it records only stresses (no strain option available) and moreover I need to specify each component and element. Is there a better way to get stresses and strains of all elements for all time steps?.



Thanks in advance

Regards,
Bruce

[Prof. R.L. Taylor]

please send your solve_mpi file or any files you use

[Bruce Wayne]

I am attaching the files here Professor.

[Prof. R.L. Taylor]

When you apply displacement b.c. you need to also fix the dof's with BOUN type commands.  Note you are missing the SURFace command on the CSURF commands.  I am using a standard solve_mpi which is what you sent.  The error is in the Imacro file.

You can output files for "paraview" to display, you can also use feap "SAVE" commands and then reinput to view.

[Bruce Wayne]

Thanks for the reply Professor.

I have fixed DOFs using BOUNdary command and included the SURFACE command in CSURF.

But the *D4TRIU WARNING* still persists and convergence is not taking place. Plastic deformation is also not happening when iterated over time. (History variables are not saved ).

I don't know where I am making the mistake. I am including those files.

[Prof. R.L. Taylor]

Since  the problem is in the macro scale problem defined in Imacro you should first replace the rve with a standard elastic material and correct the errors.

To correct the errors review the Omacro file to discover which of the data inputs did not get used.  Remember you need boundary conditions "fixed" for and degree of freedom you want to have a specified displacement value.

Once the serial version of the problem is working you should be able to replace the elastic material by the rve.

[ad10]

Dear all,

Is there any way to locate the meaning of ERROR or warning in the manual/script? Because then it will be easier to find actual meaning and work on it.

[Prof. R.L. Taylor]

There is no list currently in the manual.  This warning comes from the equation solution routine detecting the matrix is singular, or nearly is singular.  Generally it means there is a missing boundary condition.  If using standard elements using the command CHECk will display some information.

You should always check the "O" named file to make sure all the commands you used performed as you expect

[Prof. S. Govindjee]

The other thing that is useful to do when FEAP prints out an error, is to search the source code for the error message.  This will immediately tell you where the error was generated and allow you to back trace its origins.