### 2.1.9. Modeling Groups

Modeling Groups define composite lay-ups. Before working with a Modeling Group, it is necessary to specify an Oriented Selection Set and a Material (Fabric, Stackup, or Sublaminate).

The ply definition can be organized into Modeling Groups. These Ply Groups have no influence on the ply-ordering and definition but help to group the composite definitions. It make sense to define one Ply Group for each substructure (for example, hull, deck, bulkhead for a boat).

Within a Modeling Group, plies can be created. The lay-up is defined as it would be in production. The first ply is also first in the stacking sequence. The lay-up can be tailored by specifying the Orientation, Layering, geometrical Selection Rules, Draping Settings and Edge Tapering for each ply.

A lay-up can also include an Interface Layer for carrying out a fracture analysis of a composite solid model in Mechanical. The interface layer is a separation layer in the stacking sequence. It can be used to analyze the crack growth of existing cracks. The crack topology is defined with an interface layer in ACP while all other fracture settings are specified in Mechanical. The interface layers are exported as INTER204 or INTER205 elements and can be used to set up a Cohesive Zone Model (CZM) or a Virtual Crack Closure Technique (VCCT) analysis. They can also be used to define contacts zones between two layers. For more information, see Interface Delamination and Contact Debonding in the Mechanical User's Guide.

Lay-ups can also be defined or changed using the Excel Link interface. Changes can also be made by importing or exporting the lay-up as a .CSV file.

Release 18.2 - © ANSYS, Inc. All rights reserved.