Applying Local Coordinate System for BC in Abaqus

[Ariana_]

I am trying to apply a zero displacement BC in a local coordinate system in Abaqus. I have a trapezoid where the left-hand side is at some angle. I would like to constrain its motion in the x-direction with respect to this angle.

To do this, I use the Create Datum CSYS: 3 Points (rectangular) under the assembly section. I select the origin to be the node on the bottom of the left-hand side of the trapezoid, the point on the x-axis to be a node higher up on the left edge of the trapezoid, and a random point on the trapezoid to lie within the XY plane. I then create a BC, making sure to select the newly created datum as the CSYS and selecting the whole left edge, then select 0 displacement in U1.

When I view the x-displacement results, using the local coordinate transformation, however, there is still displacement along the left edge. From what I've found online, this should be the correct workflow, so I'm not entirely sure where I'm going wrong.

 

[FEA way]

Yes, the workflow is correct. Here’s what you can check:
- local X displacement values - are they significant or numerical zeros ?
- is the local CSYS displayed as you want it to be oriented ?
- is there a *TRANSFORM keyword in the input file ?
- what if you run a frequency analysis and examine the mode shapes ?