Interface "contact" forces

I am trying to calculate the “contact” forces between two bodies. Looking at the example “Axial and Lateral Loading of a Concrete Pile”, the best way to do so is using the interface function and doing the product of node area * (normal stress * axial component + shear stress component).

Is it safe to assume that the shear stress components use the global coordinate system and not a local one based on the face orientation (i.e. as the contact shear does in PFC).

Thank you

Hello @mprevitali
For interfaces, I believe the best way to calculate the normal and shear forces at the interface nodes would be like you mentioned - using the normal and shear stresses and multiplying by the node area. This really isn’t like PFC style contact forces.

However, the new addition of zone joints in FLAC3D 9.0 and greater does include new joint logic that is based on PFC contacts - you can find more information on this new feature here - Zone Joints — Itasca Software 9.1 documentation