4 Point Bend Test on a Corrugated Composite with Stiffening Rods Using Abaqus 1

[Chris Deegan]

I am trying to validate the work conducted in

https://doi.org/10.1016/j.compositesa.2005.10.015.

I have been able to simulate the basic corrugated composite but I'm having difficulty simulating the corrugated composite with stiffening rods.

Depending on the starting locations of the supporting and loading beams I am finding warnings such as:
***WARNING: THERE ARE 5 UNCONNECTED REGIONS IN THE MODEL.
***WARNING: SOLVER PROBLEM. NUMERICAL SINGULARITY
***WARNING: There is zero MOMENT everywhere in the model based on the default criterion. please check the value of the average MOMENT is small enough to be treated as Zero. if not, please use the solution controls to reset the criterion for Zero MOMENT

I have attached the solution with the fewest warnings. The set up works until I include the stiffening rods and apply constraints.

 

[FEA way]

You can find the location of unconnected regions when you run datacheck analysis with unconnected_regions=yes command. Abaqus will create sets with nodes and elements belonging to these regions. Unconnected regions are normal in some cases but it’s good to check them.

Numerical singularity indicates underconstraint. This in connection with unconnected regions warning would suggest that ties or contact interactions are not defined properly. For ties you may have to increase adjustment tolerance.

Zero moment warning is usually harmless.

Apart from checking all boundary conditions and interactions to make sure that there are no rigid body motions you can use tricks such as automatic stabilization (in step settings) and contact stabilization. But do this only when you are sure that all BCs and interactions are working properly.