Early buckling of bracket

[Gov45]

Hello,

I had a general question.

I have a frame and a bracket, bracket is mounted onto the frame.

Case - 1
When load is applied on the bracket, it buckles at 45 kN.

Case - 2
I initialized plastic strains on the frame (not on the bracket) using *initial conditions,
Now, when load is applied on the bracket, it buckles at 43 kN.

The reason the bracket buckles at 43 kN is because the frame has become more stiffer due to initial plastic strains (strain hardening) as a result there is no much load transfer to the frame and the bracket buckles early ??

There is more displacement of the bracket in case 2 at the end of loading.

With Best Regards

 

[FEA way]

The reason the bracket buckles at 43 kN is because the frame has become more stiffer due to initial plastic strains (strain hardening) as a result there is no much load transfer to the frame and the bracket buckles early ??

There is more displacement of the bracket in case 2 at the end of loading.

You should look carefully also at the other results (like stresses/strains) in the whole model and check the scaled deformed shape in different increments (slow animation may help). Use 2 Abaqus/Viewer viewports aligned next to each other to do this comparison side by side. This way you should see any visible differences in how the structure works (responds to load) in both cases. I assume that you are using a nonlinear buckling procedure like Riks, for instance.

 

[SWComposites]

You need to provide buckling mode shape plots for both cases.
And why are you concerned with the result?
Structural members should have good margins against buckling, except for crash energy absorption analyses.