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Moment not being taken when defined with a remote point

Moment not being taken when defined with a remote point

Moment not being taken when defined with a remote point

(OP)
Hi All,
I'm currently trying to solve an analysis in Ansys 19.1 (Workbench) which contains a Hub with a pipe (riser) arrangement.
The hub is arrested at the bottom by other components of the assembly and I need to apply an axial force and Moment on the other end of the riser.
I have taken a Half symmetric model and run the analysis for with the following load steps
LS-1 : Energize the gasket
LS-2 : Apply test pressure
LS-3 : Relieve test pressure
LS-4 : Apply design pressure and Hydrostatic end effect force
LS-5 : Apply Axial force (Tensile)
LS-6 : Apply Moment

I've defined the tensile forces directly on the face of the riser at LS-5 using 'Coupled' behavior among other available behaviors.
But, for moment, I've created a remote point exactly on the symmetric plane and with behaviors and results as mentioned below:
1. Remote point with rigid behavior - Moment is being taken early in the analysis at LS-2 itself where I've not applied any moment and as a result,
elements are getting distorted and the analysis is being shut down abruptly because of excessive plastic strain exceeding the default value of 0.15
2. Remote point with Deformable behavior : Moment is not being taken
3. Remote point with beam behavior with high Young's modulus : Moment not being taken

Is it because of the same surface having different formulations for Tension and Moment loadsteps?

Any kind of help regarding this will be very helpful.

Thanks in advance everyone.

PS: I've tried the Rigid behavior formulation for Tensile force load step but the problem is that the surface is not moving axially but getting bent. Which is not the behavior I'm looking for.
So I chose the Coupled behavior formulation.

- Alpete

RE: Moment not being taken when defined with a remote point

It could be a result of applying multiple constraints equations (remote force, remote point, ...)
on same surface (=same nodes). Try deactivating loads in addition to setting the value to 0 when
they are not active. Either deformable or rigid behaviour should be sufficient.

If you have defined a remote point with rigid behaviour, it is applied to every load step,
even though there is no load defined using it. It constrains the selected nodes not to move
in relation to each other.

Please post some pictures.

RE: Moment not being taken when defined with a remote point

I ran a test model and encountered the same issue (moment is not shown in reaction moment).
Try using either deformable or rigid behaviours for the loads and it should work.

RE: Moment not being taken when defined with a remote point

(OP)
Thank You LK.
I will definitively try this and report it back to you.

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