Interaction manager

An interaction describes how two surfaces behave when they touch: how much they may penetrate, whether they can separate again, and how much shear they transmit.

Defining an interaction and using it are two steps: the manager creates the definition, and the Assign contact branch of the data tree applies a named interaction to a master and slave pair.

Open the manager with the button in the numgeo toolbar, from numgeo → Manager → Interaction, or from the Assign contact branch of the data tree when picking an interaction.

Window layout

The Interaction list on the left shows each definition with its normal and tangential model, so the essentials are visible without opening it. New, Duplicate and Delete act on whole interactions.

Apply & Save and Close sit at the bottom right, and Use selected interaction appears when the manager was opened from the data tree.

Tabs

Tab	Holds
Normal contact	Behaviour perpendicular to the surfaces — penetration, separation and adhesion
Tangential contact	Friction along the surfaces
Contact options	Numerical settings for the contact search

Validation

Interactions are checked when Apply & Save is pressed. The name must not be empty and must not contain commas or line breaks; the rules that belong to a particular tab are described on that tab's page.

A problem shows a warning naming it, and the interaction stays open so it can be corrected.

The underlying commands are described under Contacts in the numgeo reference manual.