The Shell Properties and Interface Selection Sections
The physics features can be of two, fundamentally different, types: Those who act on the layers themselves, and those who act on the interfaces between layers. The settings for these two types of features are slightly different.
The Shell Properties Section
Almost all layer type of physics nodes that you add in the Layered Shell interface have a section named Shell Properties. Selections in this section interact with the standard selections of geometrical objects (boundary, edges, or points) in order to provide a complete specification of where a material property or boundary condition is to be applied. The default selection is typically inherited from the selection in the physics interface, or from a parent node.
The Use all layers check box indicates that all layers within the geometrical selection are used as selection. Only layers that are selected in the physics interface and parent nodes are considered, though.
When Use all layers is deselected, you will be presented a list of all applicable layups defined by Layered Material Link, Layered Material Stack, and Single Layer Material nodes in the component. If the parent node has Use all layers selected, all such nodes are selectable. If not, the same selection as in the parent is the only option.
When a single layup is selected, you can usually select individual layers within it. There are some exception, because for some physics features it is not meaningful not to act on all layers.
The Interface Selection Section
Almost all interface type of physics nodes that you add in the Layered Shell interface have a section named Interface Selection. Selections in this section interact with the standard selections of geometrical objects (boundary, edges, or points) in order to provide a complete specification of where a material property or boundary condition is to be applied.
You can only select interfaces that are adjacent to a layer selected in the parent. Some boundary conditions also impose other restrictions for physical reasons.
The interface selection in the Apply to drop-down also provides a number of shortcuts:
If all layers in the laminate are selected by the parent, then Exterior interfaces means top and bottom. If not, it means all interfaces that are ‘free’ in the sense that they have a selected layer on one side only.
If all layers in the laminate are selected by the parent, then Interior interfaces means all interfaces except top and bottom. If not, it means all interfaces that have a selected layer on both sides.
When All interfaces is selected, it applies to all interfaces of layers selected in the parent.
For a general description of layer selections, see Layer and Interface Selections in the documentation for the Composite Materials Module.