Shell Definition PropertyManager

The Shell Definition PropertyManager is used to define the thickness of thin and thick shell elements. You can also define a shell as a composite for static, frequency, and buckling studies.

To open the Shell Definition PropertyManager:

  • In a Simulation study tree, right-click a shell body definition, and select Edit Definition.

Type

  Thin Uses the thin shell formulation.
In general, use thin shells when the thickness-to-span ratio is less than 0.05.
  Thick Uses the thick shell formulation.
  Composite Defines a shell as a composite laminate.

A composite shell definition is available only for surface geometries in static, frequency, and buckling studies.
  Selected Entities This option is visible when you define a shell body with the option Define Shells by Selected Faces. Select the shell faces in the graphics area to edit their specifications.
  Shell Thickness Specifies the shell thickness. Lets you enter the thickness and select units.
  Flip shell top and bottom / Flip selected shell top and bottom) Flips the top and bottom faces of all shell elements that belong to the selected shell body.

Option Flip selected shell top and bottom is visible when you define a shell body with the option Define Shells by Selected Faces. In this case, you can flip the top and bottom shell faces for elements that belong to one or multiple shell faces listed in Selected Entities. Each shell definition stores its own top and bottom shell face specification.

Select Full preview to visualize the shell thickness and the orientation of the top face (green color) and bottom face (orange face) of the selected shell body. The Offset option controls the position of the shell mesh.
  Full preview / No preview Renders the thickness of the shell and the location of the top face (green color) and bottom face (orange color) of the shell with respect to the midsurface.
  Composite (Available only for surface geometries in static, frequency, and buckling studies). Defines the shell as a composite laminate.

Composite Options

Available only when you model composite shell surface for static, frequency, or buckling studies. You can apply these options to a shell or a group of shells through multiple selection.

  Sandwich Selects the sandwich composite formulation.
  Total Plies Sets the total number of plies for the composite laminate. Available only when Sandwich option is cleared.
  Symmetric Specifies a symmetric layup of laminate about the laminate mid-surface. Available for editing only when Sandwich option is cleared.
  All Plies Same Material Applies the same material properties defined by Select material option to all plies.
  Rotate 0º Reference Redefines the stripes on the composite shell so that the earlier 90º ply angle now corresponds to 0º ply angle. The option applies to all faces of a shell definition.
Unit Specifies the unit for the ply thickness.
  Ply angles relative to ply 1 Defines the ply angles of the stack relative to the orientation of the first ply. For example, if ply angle 1 is 45º and the absolute value of ply angle 2 is 60º, then the relative value of ply angle 2 with respect to ply angle 1 is 15º. The first ply angle is always absolute. The angle cells of the subsequent plies turn yellow.
  Composite shell plies Specifies the Thickness, Angle, and Material for each ply in the table.
Ply: Angle Lets you move the slider to set the ply angle for selected ply in Composite shell plies table. Alternatively you can enter the value for ply angle in Composite shell plies table. Valid angle values are between -90 to 90 degrees.
The Ply: Angle: sets angle definition for all faces of the part and does not allow local control for an individual face.
  Show other composite shells Select to show the ply angles of the other composite shell definitions that exist in your model.
  Surface Mapping Uses the surface mapping technique based on the UV coordinates of a surface to determine the zero degree ply angle reference. By default, the U direction represents the 0º reference. You can align the 0º reference with the V direction using the Rotate 0º Reference option.
  Save stack to file Saves the composite stack information to files with .csv or .txt extensions.
  Load stack from file Populates the saved composite stack information. Lets you edit and use the information to define the composite shell.

Composite Orientation

Available only when you model composite shell surfaces using the surface mapping option. Composite orientation options allow you to control the ply orientation of each face separately.

Body/Shell Available only when multiple shells are selected from the Simulation study tree. Allows you to select a surface body from the drop menu to which orientations are applied.
Selected Entities Selects a face to which material orientation changes apply.
  Mirror Orientation When toggled, the direction of the blue arrow of triad is flipped. As a result ply angle definition changes from counter-clockwise direction to clockwise direction or vice versa.
  Rotate Orientation Rotates the stripes by 90 degrees along the surface of the ply. This option is similar to the Rotate 0º Reference but allows control for individual faces.

Offset

The Offset options allows you to control the position of the shell mesh. You can position the mesh on the middle, top, or bottom surface of the shell body, or on a reference surface specified at a fraction of the total thickness. The shell mesh is created at the selected surface. The Offset options are also available for composite shells.

Middle Surface The selected surface is the midplane reference of the shell body.
Top Surface The selected surface is the top surface of the shell body.
Bottom Surface The selected surface is the bottom surface of the shell body.
Specify Ratio The selected surface is a reference surface defined by an offset value that is a fraction of the total thickness. The offset value ranges between -0.5 and 0.5.
A ratio of 0.5 positions the selected surface at the top face of the shell. A ratio of -0.5 positions the selected surface at the bottom face of the shell.
After creating the mesh, observe the orientation of the top and bottom shell faces and display the shell thickness for better visualization. Shell bottom faces have orange color. You may need to flip the shell elements to align the shells with the required orientation. Select a face (or faces) of a shell body and from the Mesh shortcut menu, select Flip Shell Elements. If you need to remesh the model, the current specifications for the top and bottom shell faces are not retained and you may need to redefine them after remeshing.
The program does not offset load and boundary condition definitions applied on the selected surfaces. Apply all loads and boundary conditions at the selected surfaces where the shell mesh is created.