Node Stiffness 1

[heaven14]

Hi all,

I am trying to run a simulation using the Abaqus/Standard solver on a cubic mesh with 1D truss elements using a steel material model. I want to apply a displacement-based boundary condition on nodes located on 1 face of the cubic mesh and a fixed boundary condition on nodes located on the opposite face of the cubic mesh.

My simulation works for a small mesh (Image 1), but fails for a larger mesh (Image 2). I noticed that the simulation works for a larger mesh only if the displacement value is very small. When I view the results of this simulation, elements that are located very far away from my initial specified elements begin rotating freely. I expected all the elements of the mesh to incur a displacement only if I specified a displacement or an adjacent element was subject to a displacement, however this is not the case in my simulation.

Questions I would like to ask:
1. Am I missing some type of constraint in my problem to restrict the motion of connected elements?
2. Does each element behave individually, even though the mesh is imported as a single Abaqus part?
3. How do I analyze my mesh as a single steel part, rather than many steel trusses joined together individually?

 

[FEA way]

I assume that you are using general contact, right ? Edge to edge contact will be crucial here. Beam elements would be better than trusses. And in this case, you should be careful with the mesh size vs beam radii so that there are no initial intersections.