Normal force from contact pressure (CPRESS in Abaqus)

[gizmo85]

First of all, hello to everybody. This is my first post here but I already use this very forum as a source of information

My problem is this the next:
I'm doing some basic contact analysis in AbaqusCAE 6.7. I have two 3D solids which are in contact (2 planar surfaces). As a result I get a contact pressure distribution (CPRESS) on the bottom solid. Now I would like to get an equivalent normal force from these result but I don't know how. Could anyobody help me please?

On this picture you can see the contact pressure distribution:

http://img256.imageshack.us/img256/2005/cpress.jpg

 

[EdR]

Integrate the pressure over the area it acts on to get the force...

Ed.R.

 

[gizmo85]

Yes, I know know that i must integrate the pressure over the area, but I unfortunately don't know how to do this in Abaqus...

 

[EdR]

Then you might have to do it the old fashioned way...Make a diagram and integrate it manually.....

Ed.R.

 

[xerf]

Have you tried requesting total contact forces?

 

[gizmo85]

Thank you xerf! I found out that if I check in the History Recquest Output the CFN box (total forces and moments due contact pressure) I get exactly what I want. It's a very convenient and elegant menthod for getting this result.

 

[sharpedge]

you have to be very careful using direct normal or tangential forces calculated by Abaqus in any contact analysis. you need to understand fully how abaqus simulates contacts and how it derives forces for each given contact formulation abaqus uses. Barely ticking CFN in the Field output doesnot mean you are getting the right Normal forces.

I would advise you read the section on contacts "Abaqus Analysis Manual" if you haven't done that already. You would be in fully control of your Abaqus Contact simulation once you grasp the theory behind the formulation Abaqus uses and you would be able to detect when Abaqus computes a seemingly "wrong" Forces or body Stresses..