ABAQUS Python scripting to define geometric imperfections

[g.alshamsi]

Hey all,

I've been facing an issue in defining imperfections in an assembly I've been analyzing using both explicit/implicit solvers; my problem is as follows:

I'm modeling a steel shear wall assembly consisting of two back-to-back beam parts, two back-to-back column parts, and an infill steel sheet part sandwiched between the built-up columns/beams. An elastic-perfect plastic material model has been defined (based on coupon test results), connections between the steel members is defined via mesh-independent fasteners, and a fixed BC is assigned at the bottom of the wall. NLGEOM is turned on.

I introduced imperfections to the model as a linear superposition of buckling eigenmodes by first performing buckling analysis and extracting the most critical buckling modes. However using this method only accounts for the buckling in the sheet itself. I need to account for imperfections in the columns as well.

I understand that I can edit the nodes in the .inp file however I don't have the exact imperfection patterns for the columns.

My colleague suggested that I model the columns separately and extract the buckling modes of the columns, then through the use of a python scripts export the deformed mesh to my shear wall assembly.

My question to more experienced users, is such a procedure possible? I'm fairly a beginner when it comes to scripting so I'm not sure if I'm heading towards the right direction. If not, does anyone have any other suggestions? I can provide any other info/files if it would help solve the problem.

Cheers,

 

[FEA way]

You can import deformed shape even without scripting: File —> Import —> Part and switch to odb file type.

But if you need to write a script the this thread can be helpful:

https://www.eng-tips.com/viewthread.cfm?qid=178458

 

[g.alshamsi]

Thnx, I'll give it a test!

 

[g.alshamsi]

Thanks to FEA way's suggestion, I found a solution.


For those who are interested, I modeled the columns alone and applied an initial imperfection equivalent to the first buckling mode scaled by a small factor (0.1). Then imported the orphan mesh of the deformed columns to the shear wall model. The orphan mesh was then converted to a part using the "Create geometry from mesh" plug in.

The plug in can be found from the following link: Link

Cheers,