Tuesday, April 21, 2009

Abaqus: Deciphering .dat files

Understanding .dat files is the first step to understanding why your simulation didn't work. First you will know the simulation didn't work because there is an .0db_f file or you look at the .odb file and the simulation ends before it gets to the end of the last time step. Second open the .dat file and scroll to the bottom and it will tell you the total number of errors. Just because it says you have 15 errors doesn't mean you have 15 problems. Most of the time one error in the program will show up multiple times. Third scroll through the .dat file finding where it lists the errors and try to correct them with the .inp file open at the same time. Use kwrite instead of kedit to view and edit multiple large files at one time. In case of a very large file you might have to open it with a text editor.

For example if you define the element type to be C3D8 instead of DC3D8 for a heat transfer analysis you will end up with perhaps eight errors on the .dat file. Often the problems are created by editing the input file and not copying and pasting the correct value. 

For example if you want to apply a load to PickedSet12 in one of the steps be careful to make sure if is _PickedSet12 or just PickedSet12 by looking into the Assembly section and noting the number of underscores that precede the set name. If there are two underscores in the Assembly section then you need one underscore in the Step section. Similarly one underscore in Assembly means no underscore in Step. It is important to make sure that what you reference in each step is the same thing that the program reads  from the Assembly information. 

Another common problem can be not defining hourglass stiffness. Solve that problem by deleting an R at the end of the element type. For example C3D8R becomes C3D8.

No comments:

Post a Comment