Hallo Arun,

in the Abaqus User Subroutines Reference Guide (1.1.5 DLOAD. User subroutine to specify nonuniform distributed loads) you will find the template for DLOAD.

Regards, Henry

Hi,

Thanks for your email. I got the template for DLOAD. My problem is that I will have pressure on the surface for each time step. How do I call every single file in the DLOAD subroutine for every step in my analysis.

Arun

The pressure is not constant. It's pressure in each element of the FE model and one file for each delta t time step.

I don't understand your problem: The subroutine DLOAD gives for example the TIME and the NOEL (number of the element). With these parameters it is possible to give each element a pressure depending on the time.

I have a text file with pressures on each elements which is varying with time. These are exported from my CFD code. I need to run a transient analysis for these laods which requires a DLOAD sub routine. The DLOAD sub routine needs to be able to read this txt file( an external file) every step and solve. an example of the load at a time step is attached.

Do you use identical meshes for CFD and CAE?

No, They are different but in my CFD software I import the FE mesh and map the CFD fluid forces and write it in the .nip file shown. The element number shown in the .inp file is of the FE surface mesh. The forces on the CFD mesh are interpolated using least sqaure method.

Arun

Maybe like this:

*DLOAD

ELSET_1, P1NU

ELSET_2, P2NU

...

Nonuniform pressure on face n with magnitude supplied via user subroutine DLOAD.

Abaqus call the SUBROUTINE DLOAD for every element (given by *DLOAD) and for every time increment/iteration.

Check the time - TIME(1) or TIME(2).

Check the element with NOEL and the load type with JLTYP.

Read your data file and search the data for this element and time.

Set the pressure amplitude F to these data from the data file.