Abaqus warning_zero force

[Tinni1]

Hello,

I am conducting a 3-point bending test of a cold-formed steel track section in Abaqus.
First I did a linear buckling analysis.
Following that I am doing a post-buckling analysis, taking scaled buckled mode shapes from the buckling analysis in the post-buckling analysis.

The beam is simply supported at both ends.
This supports I have created with discrete rigid plate elements. These elements are connected at both ends of the beams with a tie constraint. The boundary condition has been applied at the reference point of the rigid plates.

For applying the load I have created another discrete rigid plate as the applicator. This plate is connected with surface-to-surface contact with the top flange of the beam.

I am applying displacement control loading the reference point of the rigid plate in the loading step. In the initial step, other than the Y degree of freedom all the other degrees of freedom are constrained.

For post-buckling analysis, I am using dynamic implicit quasi-static analysis.

I am getting the below warning :
There is zero FORCE everywhere in the model based on the default criterion. please check the value of the average FORCE during the current iteration to verify that the FORCE is small enough to be treated as zero. if not, please use the solution controls to reset the criterion for zero FORCE.

Could you please advise, how I can remove this warning?
I tried removing the contact definition between the applicator(rigid plate that is being used for applying the load) and the beam top flange and applying a tie constraint. Still the same warning I am getting.

A pic of my model is attached below:

 

[FEA way]

Are there any other warning or error messages ? Does the analysis converge after all ? Check the model for overconstraints.

 

[Tinni1]

The analysis does not converge, after a few steps, it is aborted.
How should I check over the constraint and remove it from my model?

 

[FEA way]

What about other warnings/errors ? They may indicate the source of the problem.

Overconstraint means that multiple constraints are applied to the same DOF of particular nodes. It may concern duplicated boundary conditions, BCs mixed with MPC/coupling/tie constraints and so on.

 

[Tinni1]

It looks to me that the other warnings are not giving me any indication.
They are as below:
"The parameter hourglass = enhanced on the section controls option is relevant for these elements: c3d8r, cax4r, cgax4r, cpeg4r, cpe4r, cps4r, m3d4r, s4r, sc8r and their hybrid, thermal and pressure counterparts wherever applicable. It is also relevant for all types of modified triangular and tetrahedral elements. This warning can be ignored if the feature is applied to these element types only.

OUTPUT AT EXACT, PREDEFINED TIME POINTS WAS REQUESTED IN THIS STEP. IN ORDER TO WRITE OUTPUT AT EXACT TIME POINTS SPECIFIED, Abaqus MIGHT USE TIME INCREMENTS SMALLER THAN THE MINIMUM TIME INCREMENT ALLOWED IN THE STEP. IN ADDITION, THE NUMBER OF INCREMENTS REQUIRED TO COMPLETE THE STEP WILL IN GENERAL INCREASE".

Additionally, I checked that there is no overconstrained warning in the message file.

I tried the post-buckling analysis without applying imperfections from the buckling analysis, and the model ran well.
Whenever I am applying imperfections from buckling analysis using the below commands in the keyword section, I am getting the zero force warning.
*IMPERFECTION,FILE=Job-1,STEP=1
1,0.2744
Is it the imperfections that are causing these warnings?
What is your view?
In that case how should I approach this problem?

 

[FEA way]

Maybe try with dynamic explicit step instead of dynamic implicit.

 

[Tinni1]

Thanks!, will do that.