#### 2.1.14.1. Solid Model Properties

The Solid Model Properties dialog is divided into the following tabs:

- General
- Drop-offs
- Export

##### 2.1.14.1.1. General

The General tab has the following properties:

Figure : Solid Model Properties - General

Element Sets

  Starting with a shell model and the lay-up definition, the shell elements are extruded to a layered solid element model. Select an Element Set to define the region of the extrusion.

  Important: The mid-offset option of Element Sets is not supported for Solid Model extrusion. The ply definition must be defined without this option to obtain the correct solid model position.

Extrusion Properties

  The lay-up extrusion can be organized in different ways to merge plies with different criteria:

  - Extrusion Method:

    - Analysis Ply Wise: Extrude each Analysis Ply as one solid element layer.

    - Material Wise: All sequential plies containing the same material are grouped in one solid element layer. A maximum element thickness can be specified that will subdivide the single element layers if necessary.

    - Modeling Ply Wise: Extrude each Modeling Ply as one solid element layer (for example, every Stackup or Sublaminate is extruded as one solid element layer).

    - Monolithic: Extrude the whole lay-up in one solid element layer.

    - Production Ply Wise: Extrude each Production Ply as one solid element layer if possible. Depending on the model topology, monolithic modeling groups may be split in order to ensure the cohesion of the resulting solid model.

    - Specify Thickness: Plies are grouped by iterating through the laminate from the inside out..

    - User Defined: Plies are grouped by iterating through the laminate from the inside out.

    - Sandwich Wise: Plies on either side of a core material are grouped into single element layers. The core material is extruded as one element layer.

    Figure : Illustration of Solid Model Extrusion Methods

    For extrusion methods other than analysis ply-wise, see Material Handling for Different Extrusion Methods.

  - Max Element Thickness: Thickness at which a new modeling group will be introduced. If a single ply is thicker than this value it is split into layers of equal thickness no thicker than this value.

  - Start Ply Groups at: A new modeling group is introduced each time the iteration meets one of the plies specified in this option (User Defined Extrusion Method only)

  - Offset Direction: With the Surface Normal option, the extrusion direction is re-evaluated after each row of solid elements. With Shell Normal option, the extrusion direction stays defined as shell normal.

    Figure : Extrusion Direction

    An example of both options is shown in the following figure:

    Figure : Offset Direction

    Solid Model with Surface Normal Direction
    Solid Model with Shell Normal Direction

Drop-Offs and Cut-Offs

  The Drop-Offs and Cut-Offs section controls the global material handling for drop-off and cut-off elements in the solid model. The following options are available:

  - Global Drop-Off Material: This setting is used when the material handling settings for fabrics and stackups are set to Global.

  - Global Cut-Off Material: This setting is used when the material handling settings for fabrics and stackups are set to Global.

Element Quality

  ACP performs a shape check during the solid model generation. The checks are similar to Element Shape Testing in Mechanical APDL. The Solid Model feature has the option to delete elements if they violate the shape checking. Warping is not the only element shape check that is carried out but the warping factor can be adjusted.

##### 2.1.14.1.2. Drop-offs

The Drop-Offs Tab has the following properties:

Figure : Solid Model Properties - Drop-Offs

- Drop-Off Method: Define the ply's drop-off before or after the edge.

- Disable Drop-Offs on Top Surface: Deactivates drop-off elements on the top face sheet of the laminate for the selected (oriented) element sets.

- Disable Drop-Offs on Bottom Surface: Deactivates drop-off elements on the bottom face sheet of the laminate for the selected (oriented) element sets.

  Figure : Disable Drop-Offs

  Disable Drop-Offs option deactivated
  Disable Drop-Offs option activated

- Connect Butt-Joined Plies: If a composite layer ends away from a mesh boundary it tails off with a drop-off element. These drop-off elements are degenerated brick elements that are reduced from bricks into prisms. This option can prevent an element drop-off of two adjacent, sequential plies in the same modeling group. By default it is active.

  The feature is limited to plies that appear sequentially in the same modeling group. It is not possible to connect all butt-jointed plies that are arranged in a circle. This is a known limitation.

  An example of a sandwich structure with divided core material is shown below to demonstrate the use of a ply connection.

  Figure : Connect Butt-Jointed Plies

  Connect Butt-Joined Plies activated
  Connect Butt-Joined Plies deactivated

##### 2.1.14.1.3. Export

The Export Tab has the following properties:

Figure : Solid Model Properties - Export

Global Options

  - Write Degenerated Elements: Include drop-off elements and cut-off elements in the solid model export. Deactivating this option can lead to holes in the mesh and prevent import into Mechanical. Deactivating this option is not advised during a Workbench workflow.

    Figure : Write Degenerated Elements

    Export with Drop-off Elements
    Export without Drop-off Elements

  - Use SOLSH Elements: Create the model with Solid-Shell elements (SOLSH190).

  - Drop Hanging Nodes: Remove hanging nodes from model before solve. (default on)

    Hanging nodes are nodes which are not connected to all the neighboring elements. Hanging nodes can occur when quadratic hexahedral, tetrahedral, and prism elements are connected together. Hanging nodes can lead to discontinuous deformation fields and are therefore not desirable. When this option is active, element edges containing a hanging node are described as a linear shape function. The following figure shows a quadratic tetrahedral element on top of a quadratic hexahedra element. There is a hanging node on the tet element, highlighted by the red square:

    Figure : Quadratic Tetrahedral Element on Top of a Hexahedral Element

  - Use Solid Model Prefix: This option makes element components begin with the name of the defined solid model. For example, if the solid model is `BULKHEAD`, the elements are grouped into components in the following way:

    `CMBLOCK,BULKHEAD_P9L1_Plies_Top,ELEM, 600! users element component definition`

Transferred Sets

  - Transfer All Sets: All Edge and Element Sets are transferred.

  - Transferred Element Sets: Specify Element Sets for transfer. Element Sets become two separate element components with the designation `_TOP` and `_BOT`. One element component coincided with the original element set and the other one lies at the end of the extrusion path.

  - Transferred Edge Sets: Specify Edge Sets for transfer. Edge Sets are extruded to form surfaces (an Edge Set transfers to a surface element component).

  Figure : Transferred Element Sets in Mechanical

Numbering Offset

  Entity numbering is performed automatically in ACP within your Workbench project. Entities of multiple solid models in one ACP setup are automatically renumbered to avoid overlap. The automatic renumbering also takes place when different ACP or Mechanical models are combined in a single analysis system.

  The automatic renumbering is activated by default and can be deactivated in the properties of the downstream Mechanical Model cell (see Renumber Mesh Nodes and Elements Automatically).

  The entity numbering offset can also be controlled manually. Deactivate the Default option to define the offset manually for each of the entities (elements, nodes, materials, sections, coordinate systems). The numbering starts at the defined index and is incremented by one at a time.

  Figure : Properties of the ACP-Pre Setup Cell in the Project Schematic

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