Introducing Imperfection by using an Equation

[AbaqusNewbie15]

Hi,
I am trying to do a buckling analysis by introducting imperfection.
I want to introduce the imperfection using geometric equations. Because i have to compare it with an experiment that gives the ovalty of the imperfection.
I have created a set area in the pipe to introduce this imperfection. however i do not know how to implement the equations that defines how oval that part of the pipe is.

Any recommendations?

I am Using Abaqus CAE 6.13. I do not know how to use the command line. But if have to get to, i guess i have no order choice.

 

[cooken]

In CAE there is a mesh edit interface where you can apply offsets to nodes. You can interact with this using a python script (Section 18 of the scripting reference) and loop through each node in your set, using the coordinates to calculate the desired offset to change the pipe from round to oval. Based on the image provided it should be fine, but beware if you have a large number of nodes this can be quite slow.

You can also use the *Imperfection command directly in the input file and reference a separate text file containing the node offsets.