Elem Offset Panel

Location: 2D and 3D pages

The element normals provide directional information.

Solid Layers Subpanel

Before you offset plate elements, make sure that the normals of the plate elements are properly aligned.

The offset can be a negative value.

Figure 1. Elements Selected	Figure 2. Elements Created, Initial Offset=40

Figure 3. Elements Created, No Biasing Factor	Figure 4. Element Created, Negative Biasing Factor

The command function HM_COMP_TK is called to calculate each component’s thickness. This function has one argument which must be the thickness of the component.

*function("HM_COMP_TKvariable1)
 *components(""")
   *format()
       *variableset(variable1,$TK)
 *output()
*return()

A template that contains the HM_COMP_TK function must be specified in the solver interface.

Option	Action
3d faces by nodes	Select nodes of 3d elements to offset.
Delete 2d elements after	Delete 2d elements after offset.
elems to offset selector	Select the elements to offset.
along geoms to follow	Select the surfaces or elements to act as guides for the sides of the offset elements.
number of layers	Specify the number of layers of elements to build along the normal direction.
Use distr thick	Apply the distributed BL thickness ratio that you defined in the Distributed BL Thickness Ratio dialog. To access this dialog, click Set distr thick. Clear this checkbox to ignore the defined distributed BL thickness ratio.
initial offset	Specify the initial offset from the surface of the plate elements along the positive normal direction.
total thickness	Specify the total thickness of the layers of solid elements you want to create.
biasing style	Select the biasing style.
bias intensity	Specify the biasing intensity value.
elements to current comp / original comp	Choose whether to organize the newly created components in the current component, or in the components of the shell elements.
corners style	Square corners Maintain the element normals, producing sharp corners but resulting in corner elements with severe angles. Rounded corners Similar to square corners, except adjusts the element thickness as the mesh nears the corner, reducing the severity of the corner elements' angles. CFD corners Similar to rounded corners, except it does not attempt to maintain the element normals, so all of the edges of each element are adjusted to reduce the severity of their corner angles. Figure 5. Corner Style Examples. The bottom/front mesh uses rounded corners; the middle mesh uses square corners; the top mesh uses CFD corners (notice that CFD elements "lean" toward the corners).

Shell Layers Subpanel

Before you offset plate elements, make sure that the normals of the plate elements are properly aligned.

The offset can be a negative value.

Figure 6. Elements Selected	Figure 7. Elements Created with Square Corners

Figure 8. Elements Created with Rounded Corners	Figure 9. Element Created, Initial Offset=40

Option	Action
elems to offset selector	Select the elements to offset.
along geoms to follow	Select the surfaces or elements to act as guides for the sides of the offset elements.
number of layers	Specify the number of layers of elements to build along the normal direction.
initial offset	Specify the initial offset from the surface of the plate elements along the positive normal direction.
total thickness	Specify the total thickness of the layers of solid elements you want to create.
biasing style	Select the biasing style.
elements to current comp / original comp	Choose whether to organize the newly created components in the current component, or in the components of the shell elements.
corners style	Square corners Maintain the element normals, producing sharp corners but resulting in corner elements with severe angles. Rounded corners Similar to square corners, except adjusts the element thickness as the mesh nears the corner, reducing the severity of the corner elements' angles. CFD corners Similar to rounded corners, except it does not attempt to maintain the element normals, so all of the edges of each element are adjusted to reduce the severity of their corner angles. Figure 10. Corner Style Examples. The bottom/front mesh uses rounded corners; the middle mesh uses square corners; the top mesh uses CFD corners (notice that CFD elements "lean" toward the corners).

Shell Offset Subpanel

If you build a mesh on the surface of a CAD solid body, the elements will be aligned out of the object. When you use this tool to offset them to the midsurface of the solid, you will want them to go in the reverse of the element normals.

This function is very similar to the Translate panel, except that instead of moving all of the elements in a fixed, uniform direction, it moves each in a direction corresponding to the local normal of the mesh in the vicinity of that element. When the selected elements are moved, entities connected to them or to their nodes, such as loads, systems, equations, or other elements, move along with them.

Option	Action
elems to offset selector	Select the elements to offset.
along geoms to follow	Select the surfaces or elements to act as guides for the sides of the offset elements.
distance / distance = 1/2 element T	distance Specify a fixed distance to move the elements. distance = ½ element T Move the elements a distance equal to half of the material thickness of the component in which each element resides.
corners style	Square corners Maintain the element normals, producing sharp corners but resulting in corner elements with severe angles. Rounded corners Similar to square corners, except adjusts the element thickness as the mesh nears the corner, reducing the severity of the corner elements' angles. CFD corners Similar to rounded corners, except it does not attempt to maintain the element normals, so all of the edges of each element are adjusted to reduce the severity of their corner angles. Figure 11. Corner Style Examples. The bottom/front mesh uses rounded corners; the middle mesh uses square corners; the top mesh uses CFD corners (notice that CFD elements "lean" toward the corners).

Thicken Shells Subpanel

Use the Thicken Shells subpanel to convert thin shells into solid elements by making them thicker/adding a third dimension to them. When working with shells on an outer surface, you can choose the direction to extrude them; when working with shells on a midsurface, they are automatically extruded in both positive and negative normal directions.

Option	Action
elems to offset selector	Select the elements to offset.
along geoms to follow	Select the surfaces or elements to act as guides for the sides of the offset elements.
shells are on the midsurface / shells are on an outer surface	Shells are on an outer surface Form replacement shells around the selected elements. Shells are on the midsurface Form replacement shells above or below the selected elements.
thickness =	Specify a thickness value.
elements to current comp / original comp	Choose whether to organize the newly created components in the current component, or in the components of the shell elements.
corners style	Square corners Maintain the element normals, producing sharp corners but resulting in corner elements with severe angles. Rounded corners Similar to square corners, except adjusts the element thickness as the mesh nears the corner, reducing the severity of the corner elements' angles. CFD corners Similar to rounded corners, except it does not attempt to maintain the element normals, so all of the edges of each element are adjusted to reduce the severity of their corner angles. Figure 12. Corner Style Examples. The bottom/front mesh uses rounded corners; the middle mesh uses square corners; the top mesh uses CFD corners (notice that CFD elements "lean" toward the corners).

Thin Solids Subpanel

Use the Thin Solids subpanel to create thin solid meshes. The mesh is created by first generating a 2D mesh on a selected set of faces, and then extruding this mesh to generate solid hexa or wedge elements.

In order to create a thin solid mesh, the solid geometry must meet a certain criteria.

The solid entity should be a bent sheet metal solid.
You should be able to identify both the Source (start) faces and the Destination faces.
Source and destination faces must be connected by side (along) faces which are almost 90 degrees to them.
The number of top and bottom faces do not need to match.
Side faces do not need to be four-sided.

Option

Action

thin solid mesh: solids / elems

Select the solid entity or elements to create a thin solid mesh from.

auto detect / detect now

auto detect (default): Automatically detect the faces to use for the initial shell mesh.
detect now: Manually select along surfs and destination surfs. Clicking detect now populates these collectors as if using the autodetect feature, but gives you the opportunity to add or remove faces from each collector by highlighting it and left- or right-clicking faces in the modeling window.

save src to SAVELIST

Save the detected source faces in memory (and written to the command file) for easy retrieval. They are not saved to disk as part of the model.

Note: Available when detect now is selected.

along surfs / source surfs

along surfs: Surfaces that define where the edges of the extruded solid elements should fall.
source surfs: Surfaces from which the thin solid elements will be extruded.

destination: surfs

Select surfaces to be used as the target toward which the base mesh will be extruded.

number of layers:

Specify the number of layers of elements to build along the normal direction.

element size = / elem_size/thickness

element size: Specify the desired element size.

Figure 14. Element Size = 2 (3 Layers)
elem_size/thickness: Specify the ratio of size to part thickness. Since the element size is based on the part thickness, the mesh will be finer in thinner areas.

Figure 15. Elem_size/Thickness = 2 (3 Layers)

element type =

Select the type of elements used in the initial shell mesh from which solid elements are created.

R-trias are right-angle triangular elements.
Mixed uses quads primarily, but inserts trias when necessary to improve mesh quality.
Quads attempts to use quads only, but may still insert some trias where quads simply will not fit.

Figure 16. Trias	Figure 17. Quads (Equal Densities)
Figure 18. Right-Trias	Figure 19. Mixed (Density 10 at Top, 5 at Bottom)

linear or no biasing / exponential biasing /bellcurve biasing

Select the biasing affects element growth in successive layers, moving away from the source faces.

No Biasing: All layers are equal in thickness.

Figure 20. Example: No Biasing
Exponential Biasing: Successive layers are exponentially thicker.

Figure 21. Example: Exponential Biasing
Bellcurve Biasing: Layers are progressively thicker near the center, but thinner near the source and destination faces.

Figure 22. Example: Bellcurve Biasing

bias intensity =

Specify the biasing intensity value.This numeric value affects how strongly the biasing effect is. When left at zero, no biasing is applied.

elements to current comp / original comp

Choose whether to organize the newly created components in the current component, or in the components of the shell elements.

Command Buttons

Button	Action
offset+	Extrude/offset shells in the positive normal direction.
offset-	Extrude/offset shells in the negative normal direction.
thicken	Perform the thickening when shells are on the midsurface. Note: Available in the Thicken Shells subpane.
mesh	Create the thin solid mesh in accordance with the criteria specified in the inputs. Note: Available in the Thin Solids subpanel.
reject	Undo any changes made to elements, or thin solid element creations. You cannot reject changes after exiting the panel, but you can still reject after switching to a different subpanel and returning.
return	Exit the panel.