Apply pressure in abaqus

[FEAppp]

Hello,
When we apply the load-pressure in abaqus. If we select pressure, I wonder this pressure is the force divided by the undeformed area or the deformed area.
In the large-displacement analysis, after the deformation, the area has changed. SO will my applied pressure be changed as well or not?
For example, original force is 10N, original area is 5m2, orignal pressure is 2 Pa (10/5). After the deformation, deformed area is 4m2. Will the abaqus keep my force the same, so the pressure is 10/4=2.5 Pa. Or the abaqus will keep my pressure the same, so the pressure is still 2 Pa, resulting my force by 2*4=8N.
Thanks.

 

[FEA way]

By default surface traction loads are integrated over the surface in the current configuration but it can be changed. You can find the details about this feature in the documentation chapter "Distributed loads" (paragraph "Resultant loads due to surface tractions").

 

[FEAppp]

Hello FEA way,
Thanks, as for the load-mechanical-surface traction, I indeed could choose traction is defined whether per unit deformed area/undeformed area.
What about I just using the load-mechanical-pressure for the normal stress?? In editing the pressure dialogue, it doesn't specify whether it's deformed area or undeformed area.
Thanks.

 

[FEA way]

Actually, you can define pressure using general surface traction load by specifying proper direction vector (so that the load is normal to the surface). There’s even an example like that in the documentation paragraph that I referenced in my previous reply.

 

[FEAppp]

Thanks FEA way! Yeah, I saw that. I will always use traction instead of pressure then since the traction will let me choose which area I want.

 

[Mustaine3]

A pressure load will be updated with the deformation when NLGEOM is activated in the step.

You can test that with a simple block. Fix it on one side, apply a pressure on the other side. Then cool it down a lot to get a large change in size and check the reaction forces at the boundary condition.

 

[FEAppp]

Thanks Mustaines, it's a good suggestion!