abaqus is not recognising my imperfection input from buckle analysi 1

[AIO07]

Hi all,

I ran a buckle analysis to get the buckling modes and then copied the .fil and .prt files with the cae file to a new folder, renamed the .fil and .prt files. I also replaced the buckle step with a Rik's analysis step. I then remove the modal file and node file commands in my keywords. After doing all these I ran the risk analysis, the structure just behaves like there is no imperfection inputed. So, I thought to remove the imperfection file and the structure behaves excatly the same way. I dont know why Abaqus doesnt recognise the imperfection.

PLEASE HELP.

 

[bassmanjax]

Did you add the *IMPERFECTION keyword into your Riks analysis input file?

Martin Stokes CEng MIMechE

 

[AIO07]

YES I DID

 

[bassmanjax]

Okay, there are a few things to look at then.

Did you use the first buckling mode as the trigger, or a combination of modes?

What scaling factor are you using, and how did you decide what factor to use? For shells, I use a percentage of the shell thickness to start, say 10%.

I used to try a number of scaling factors, and then plot them against the collapse load to see what effect it was having on the structure.

Martin Stokes CEng MIMechE

 

[AIO07]

I did use the first mode and varied my scaling factor from below 1 and up to 100 still its the same.

I tried running the Riks analysis without the imperfection file, and the results i am getting is exactly the same as when i included the imperfection file, so i presume its not seeing it at all.