Define boundary conditions in Abaqus

[optimus2007]

While modeling a 2-d human hip joint I need boundary conditions,
One constraint is that the end of the femur is fixed.
How can I define this in Abaqus?
Do I need a reference point?

Many thanx for helping

 

[corus]

A hip joint in 2D? I'm not sure that would be a valid assumption to make. However relating to your question, reference points are generally for rigid parts, and my hip seems far from rigid just now.

Tata

 

[OptiEng]

In terms a boundary conditions, are you trying to model real gait loads , i.e. walking cycle or just max load i.e. 2000N. By assuming the end of the femur is fixed, you could just constrain the bottom edge of the end of the femur (U1, U2 and UR3). If you are new to abaqus I recommend the abaqus manuals (Getting Started with Abaqus: Interactive Edition). Hope this will help.

 

[optimus2007]

thankx for posting cpomments.
first of all i want to consider static case.
I have put a sketch in the attachment.
Maybe this hepls understanding my problem.

 

[tgrimley]

You don't _need_ a reference point.

Assuming an X-Y plane, pick the bottom edge and constrain all in U2 and UR3. Then pick a node and constrain in U1. Or do the whole bottom edge in U1,U2,UR3 and ignore the corner stresses at the BC.

 

[optimus2007]

Many thanx.
Concerning the other loads like weight force,
i have tried to define it, but the problem is the arc.
How can I fix it?

 

[tgrimley]

Weight force.. if you're talking about the pressure loading in the attached diagram.. you can try defining a reference point outside that range, use a distributing coupling between the ref point and that surface, and then apply your loads to the reference point. It's still a bit unclear what you're interested in..

 

[optimus2007]

Well, I am interested in what happens between femur head and pan.

 

[optimus2007]

@tgrimley

thank you for the tip.
I have ued a distributing coupling surface/ node.
But the wished effect is not reached
the max. tension has to be top left and not downright

 

[Drej]

Firstly, I agree with Corus - the basis of your assumption (plane strain, presumably) is highly questionable at best. Is this a student exercise by any chance? Secondly, I'm struggling to understand what your "boundary conditions" are trying to represent, which is why I ask whether this is likely to be an academic exercise.


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