Reaction Forces Across Contact Interface

JohnM

We often have a need to look at the load across a contact interface. See figure and simple model.

In this case, the contact force will be 1100N, which we can infer from the ground reaction. But in many cases, the redundant load paths/multiple contact surfaces makes this method not applicable. We have "tricks" to extract these loads, but they are all a little clunky. I'm looking for a simple way to determine the load across this contact surface.

Any takers?

Victor

If the contact surface is flat, you can use Solution -> Surface integral on the contact stress pressure solution variable and the slave contact surface. Here it shows 1098 N which is pretty close to 1100 N.



If the contact has friction, do it again with each of the two shear components to obtain the 3 components of the force normal and tangent to the contact surface.

JohnM

Good option, thanks Victor!

We looked at the *SECTION PRINT command, which would be handy for this application, but it is very dependent on mesh density to get an answer close to correct.

We often have curved surfaces, so the current "trick" is to take all displacements on contact surface nodes, convert to *BOUNDARY inputs, suppress all contacts and re-run. It's a bit of a pain, but at least in this case the Sum command reports the correct load.