Pressure dependent boundary condition in Abaqus 1

[PaulMcNulty]

hi,

I want to create a bondary condition in Abaqus that moves a certain distance depending on the pressure applied, anyone know how to do this? I am only able to set up a completely rigid boundary condition at the moment.

Thanks for any help!

Paul

 

[burningDiesel]

If you are applying the pressure, can't you simply define a displacement with the same amplitude?

 

[PaulMcNulty]

Hi,

Thanks for your reply.

I am modelling an arch bridge. I want to see the effect of allowing the supports of the arch under vertical loading to move slightly as the horizontal pressure increases. So I don't think I can do what you are suggesting.

Paul

 

[burningDiesel]

OK So you are not applying the pressure, but you want to displace the footing according to reaction force?
Search the manual for user subroutine UAMP, used with sensors (history output -> sensors).
Also see example 4.1.2 Crank mechanism

 

[PaulMcNulty]

Thank you, I will look into that.

 

[burningDiesel]

Easier would be (but maybe not what you want) to instead of boundary condition, define a spring connector, which will act like a spring (duh) between two points (or 1 point and 'ground'). You can also define damping/'stops'/non linear spring behavior/...

 

[PaulMcNulty]

Well I have spent the last few hours trying to learn the user subroutine; I think I have to use VUAMP as im running an explicit analysis. Your right though, this is not easy, so im going to try and use a spring instead!

 

[PaulMcNulty]

I have learned how to use springs, seems pretty simple, I have a problem though. I want to put the spring onto a granular material, but I can only apply the spring to nodes and not the entire surface. So lets say my granular material was a rectangle, if I was to apply springs to the four nodes at the corners, then surely the springs will have no effect away from the corners and the backfill will simply bulge outwards as there is no restraint?

 

[PaulMcNulty]

I have an idea; could I place a thin infinitally stiff rectangle wall against my granular material, and then apply springs to the four corners of the wall. That way the entire wall would move evenly backwards with the force, right?