Tinni1
Civil/Environmental
- Sep 27, 2021
- 157
Hello,
I am performing a 3-point bending analysis of a cold-formed steel U section in Abaqus.
The end boundary conditions are pinned. The load applicator is modeled as a rigid plate.
Initially, I want to perform a linear buckling analysis, to take scaled the buckled mode shapes into the post-buckling analysis to consider the imperfections.
In the posy buckling model. I have defined contact conditions between the rigid applicator and the beam top flange.
I ran the linear buckling analysis with the same contact definition, and it ran OK and provided me with all the buckled mode shapes.
My Query is:
1. Can a buckling analysis run with contact definitions? As contact is a non-linear analysis and buckling is a linear analysis.
2. When I changed the contact definition with tie constraint I got an error-"DIFFERENTIAL STIFFNESS MATRIX IS COMPLETELY NULL. THE EIGENPROBLEM CANNOT BE SOLVED. IN A *BUCKLE ANALYSIS THE MOST LIKELY CAUSE IS THAT A NONZERO LOADING PATTERN WAS NOT SPECIFIED VIA *BOUNDARY, *CLOAD, *DLOAD, ETC,. SEE Eigenvalue Buckling Prediction IN THE Abaqus/Standard USERS MANUAL"
But I had defined unit load in my model.
Then should I consider running the buckling analysis with contact definations, as it ran OK?
Could you please advice?
Many thanks!
The pic of my model is attached herewith as a reference:
I am performing a 3-point bending analysis of a cold-formed steel U section in Abaqus.
The end boundary conditions are pinned. The load applicator is modeled as a rigid plate.
Initially, I want to perform a linear buckling analysis, to take scaled the buckled mode shapes into the post-buckling analysis to consider the imperfections.
In the posy buckling model. I have defined contact conditions between the rigid applicator and the beam top flange.
I ran the linear buckling analysis with the same contact definition, and it ran OK and provided me with all the buckled mode shapes.
My Query is:
1. Can a buckling analysis run with contact definitions? As contact is a non-linear analysis and buckling is a linear analysis.
2. When I changed the contact definition with tie constraint I got an error-"DIFFERENTIAL STIFFNESS MATRIX IS COMPLETELY NULL. THE EIGENPROBLEM CANNOT BE SOLVED. IN A *BUCKLE ANALYSIS THE MOST LIKELY CAUSE IS THAT A NONZERO LOADING PATTERN WAS NOT SPECIFIED VIA *BOUNDARY, *CLOAD, *DLOAD, ETC,. SEE Eigenvalue Buckling Prediction IN THE Abaqus/Standard USERS MANUAL"
But I had defined unit load in my model.
Then should I consider running the buckling analysis with contact definations, as it ran OK?
Could you please advice?
Many thanks!
The pic of my model is attached herewith as a reference: