Abaqus - Stresses on moving deformable part

[TheFinalSundown]

Hello,

I am trying to preform a 2D simulation on an assembly of 2 pins and a lug. The pins are inside of 2 holes of the lug and are pulled apart using boundary conditions that are attached to a reference point at the center of the pin.

The simulation runs and an output is generated, but only the lug section of the assembly ends up with a stress that makes sense, which is about 1.5GPa while the stress on the pins is only a few microPa. The field output is set for whole body, and I am using a surface to surface interaction. The deformation is plastic and I have included that in the material definition if that is an issue. The constraints I am using to connect reference point to the pin's surface is coupling, I have used the Tie constraint but when the boundary condition is applied to the RF, the pin does not move. I am not sure what the problem is so any suggestions to what could be wrong would be greatly appreciated.

Thank you all

 

[FEA way]

If it’s supposed to be symmetric then you could analyze half of the lug and pull the edge of the cut instead of pulling the pin. Otherwise, you would have to figure out how to move the pin without overconstraining it.

Also, you should refine the mesh of the lug.

 

[TheFinalSundown]

Hey thanks for the fast reply. Unfortunately the simulation is not symmetric so applying your suggestion to the lug would be difficult. I did apply what you suggested by cutting a section of the pin off so I can apply the boundary condition to the flat edge instead of a curved surface.

I don't think you can constrain the circular pin without over constraining since I was only using one constraint and I tested every type as well. I appreciate the advice though.

 

[FEA way]

You should avoid constraints (like rigid body or coupling) or limit them only to a small region inside the pin or on the other side of it (away from contact with the lug). You could apply boundary conditions directly to the pin instead. It’s usually not recommended for contact regions but it’s better than the aforementioned stiffening constraints and again, you can potentially apply them away from that area of interest.