Imperfection and cylinder buckling

[astrogirl87]

I'm relatively new to Abaqus and have just started a cylindrical shell buckling analysis. I think that to get accurate results in a Riks analysis, I need to seed my model with imperfections derived from a Buckling analysis. I've looked at the User's Manual example cited in thread: thread799-113447.

My problem is that I'm using a network administrated computer that doesn't have the correct Fortran compilers installed, so I can't run the program to create the imperfection seed file. Is there a way to specify an imperfection seed on command line or create the file by another method?

Thanks!

 

[astrogirl87]

After some more looking, I think I can insert *IMPERFECTION into my Riks input file manually. I want to apply the buckling modes I found in the buckling analysis over the entire part in Riks analysis. In the manual it says:

*IMPERFECTION, FILE=results_file, STEP=step
Data lines specifying the mode number and its associated scale factor...

However, it's not clear what results file it wants. The ODB? What is the syntax for the data lines? Could I do:

*IMPERFECTION, FILE=BuckleTest.odb, STEP=Buckle
1, .125
2, .0625
3, ...

Do I just stick this code in right before the Riks step in the new analysis? Is this all that is necessary to impose the initial imperfection on the whole part? Can I do this all in one file, or do I need to create two files, one for running the Buckling and one for running the Riks?

I'm sure these are very basic questions, but I'm just getting started, and it's a steep learning curve.

Thanks!