Plies

Ply entities define a FEA ply which is the FEA correlation to a physical ply.

Physical plies manufacture laminates which make up composite structures. A physical ply has attributes of material, shape (area), thickness, and fiber orientation; where its shape is any complex flat pattern that can be cut from a roll of material. Similarly, a FEA ply is composed of the same data attributes as a physical ply (material, shape/area, thickness, and fiber orientation). The shape of a FEA ply can either be defined by closed lines or approximated from the elements which most closely represent its actual complex shape. In the case where plies are defined on lines, perform a realization to convert this information into a definition by elements. Ply data defined on lines is imported from Catia Composites Parts Design (CPD) data.
Plies defined by elements
The shape (area) of an FEA ply is defined by selecting elements which most closely represent the complex shape of a physical ply. In Figure 1, an elliptical physical ply shape is defined by the brown line. The corresponding FEA ply shape is defined by the gray shaded elements of the associated FEA mesh. Typically, if an element's centroid exists within the bounds of the physical ply shape, that element is considered part of the FEA ply shape.


Figure 1.
Plies defined by lines
Plies can be defined by selecting lines which build a closed area. If CPD data is imported from Catia files, plies are defined on lines.
Once a mesh is available, plies defined by lines can be converted into plies defined by elements by performing a realization. Realization/conversion methods include:
Project normal to target mesh
If the element centroid projected along its normal lies within the geometrical ply definition, it is associated with this ply.
Normal by ply contour
Projection along a normal on a surface derived from the lines of a ply contour.
Specified direction
Manually define a projection direction.
The ply thickness is typically defined as the final cured thickness of a single ply of material. In addition, the ply can be made of any material: isotropic, orthotropic, anisotropic, or any other material law.


Figure 2.
The fiber orientation of a ply defines the direction fibers lay within that ply. The ply fiber orientation is typically an integer value between -90 and 90. The fiber orientation of a ply is always defined relative to each elements material direction using right hand rule around the elements normal, or thru-thickness direction, to define positive angles. Even though a ply's fiber orientation is a constant integer, element material directions can vary from element to element, and this allows varying fiber directions within a ply to be modeled. Element material directions are defined differently from solver interface to solver interface.


Figure 3.

Once all of the plies which make up a composite structure are defined, just as in the actual hand-layup manufacturing process, plies are stacked in a specific given order within the laminate entity to define a laminate of the structure. It is possible to stack plies, whether they are defined based on geometry or elements.

Turn the display of plies on/off or change the way plies appear in the modeling window with the Ply layers display setting, which can be accessed from the Mesh Display settings on the View Controls toolbar.

Supported Solver Cards

Solver cards supported for plies.

Abaqus Cards

The Abaqus solver has no direct match for a ply, therefore the ply entity does not have a card image in the Abaqus solver interface. Ply entity names will end up in the ply name of the composite properties SHELL SECTION and SHELL GENERAL SECTION, if used in a laminate entity and realized into a zone based model.

Nastran Cards

The Nastran solver has no direct match for a ply, therefore the ply entity does not have a card image in the Nastran solver interface. Ply entity IDs will end up as global ply ID in the PPOMG property card, if used in a laminate entity and realized into a zone based model.

OptiStruct Cards

The OptiStruct PLY card is represented as a ply entity. Plies can be created from the selection of individual elements or from predefined element sets which define the ply shape.

Card Description
PLY Defines the properties of a ply used in ply-based composite definition.
Note: Can only be created and edited in the Ply Editor from the Model Browser.

Radioss Cards

The property card /PROP/PLY (TYPE19) and keyword /PLY are represented as a ply entity.

Samcef Cards

The Samcef .PLI card is represented as a ply entity.

Create and Realize Plies

Overview of how to create and realize plies.

Radioss

Create Plies

  1. In the Model Browser, right-click and select Create > Ply from the context menu.
  2. In the Create Ply dialog, define attributes accordingly.
    Option Description
    Name Ply name.

    This will define the prop_title attribute of /PROP/TYPE19.
    Same as Duplicate an existing ply.
    Card Image Keyword used for the ply creation.

    /PROP/PLY if P19_PLY card image is used, or /PLY if PLY card image is used.
    Color Color of ply.
    Dummy ply Create simple ply without a card image.
    Material Type Type of material assigned to ply.
    Material Material assigned to ply.

    This will define the mat_ID attribute in /PROP/TYPE19.
    Thickness Ply thickness.

    This will define the t attribute in /PROP/TYPE19
    System Reference system used for the angle calculation of the ply.

    The system is not linked to an attribute of the /PROP/TYPE19, but can be defined by importing external composite data like FiberSim information. This information will be taken into account during the realization of the ply.
    Orientation Fiber angle on the ply.

    This will define the delta_phi attribute in /PROP/TYPE19.
    Integration points Number of integration point through the ply thickness.

    This will define the Npt_ply attribute in /PROP/TYPE19.
    Drape table Drape table to link to the ply.

    The drape table will not linked to an attribute of the /PROP/TYPE19, but can be defined by importing external composite data like FiberSim information. If specified, a realization of the ply is needed to obtain the initial fiber angle defined with the Radioss cards /INISHE/ORTH_LOC and /INSH3N/ORTH_LOC.
    Shape Shape of the ply.

    The attributes grsh4n_ID and grsh3n_ID of /PROP/TYPE19 are automatically generated.

    If the shape is defined by a line or surface, which may be the case when importing CAD/CPD data, a realization of the ply is needed to generate the FE element sets defining the FE shape.
    Base Surfaces Base surfaces to be used during ply realization.

    This is useful when the projection of the shape is not found on a unique surface.
  3. Click Create.
You can edit a ply by right-clicking on it in the Model Browser and selecting Edit from the context menu.

Realize Plies

Realize plies when ply definitions need to be imported from external composite data, such as FiberSim or CAD/CPD.

Before you realize plies, make sure the Radioss composite property card /PROP/TYPE17 or /PROP/TYPE51 is assigned to the composite components on which the realization should be performed.

During the realization process, the shape of the ply will be projected on the selected FE mesh and, if drape information is available, the corresponding Radioss cards /INISHE/ORTH_LOC, /INSH3N/ORTH_LOC, or /DRAPE will be generated.

  1. In the Model Browser, right-click on the Plies folder and select Realize from the context menu.
  2. In the Ply Realization dialog, define realization settings accordingly.
    Note: For each case (FiberSim or CAD/CPD), a dedicated projection method is proposed in the Projection options field.
  3. Click Realize.