Finite Planar Elements Properties
The Finite Planar Elements properties window in Advance Design allows detailed inspection and modification of planar element attributes used for finite element analysis, including geometry, material behaviour, stiffness, releases, meshing, and load transfer.
Navigate directly to your section of interest:
- General
- Super element
- Material
- Eccentricity
- Thickness
- Cost and CO2 calculations
- Result's grid
- Releases
- Mesh
- Behaviour coefficient
- Load Area Transfer
Accessing the Finite Planar Elements Properties
To focus only on finite element properties, select FE Properties from the Properties filter drop-down list. This action filters the display to show only the attributes relevant to finite element analysis, providing a clearer and more simple interface.
Filtering the Properties window to display dinite elements attibutes only
Using the Properties window for Finite Planar Elements
In the properties window, you can view and modify the properties of finite planar elements, allowing for detailed customization and management.
Key Features and Functions:
-
Identifier: View / modify the ID number of the element.
-
Name: View / modify the default name of the element.
Tip: Elements with different properties (material, cross section, etc.) can share the same name that can be used as a selection criteria.
-
Type: From the drop-down list select a planar element type (i.e., membrane, plate, shell, plane strain, steel deck, layered shell).
-
Active state: when disabled, the element's properties can no longer be modified.
-
Systems: View the ID of the system in which the element is located.
-
Comment: Insert observations regarding the element.
-
GTC Identifier: View the identifier automatically assigned to the element after the GTC export / import.
-
Identifier: View the ID number of the super element.
-
List: View the ID number of the elements comprised in the super element.
-
Color: View / modify the color of the super element.
Select a material type from the drop-down list or click 
to display the Materials dialog box and select a material from the available libraries.
Define the position of the planar element cross section relative to its own z axis. Input the desired value corresponding to the cross section offset relative to the z axis (expressed in the current units for cross sections dimensions).
Eccentricity
-
Enter a value for the planar element thickness using the current unit for cross section dimensions.
-
Define the planar variation by entering the variation coefficient for the x and y slopes.
-
Concrete inertia type: This setting determines the method for correcting the stiffness matrix. By default, it is set to Imposed, which allows you to manually edit the Stiffness matrix modifiers for shell or plate planar elements, and the Cracked section inertia coefficient for membrane or plane strain planar elements. When the Concrete inertia type is set to Auto, the stiffness modifiers and the cracked section inertia coefficient are disabled (greyed out). For concrete planar elements, if the Concrete inertia type is set to Auto, the cracked section inertia coefficient is automatically updated for all planar element types. This automatic update occurs when the Run additional FEM calculations to update element stiffness option is enabled in the Reinforced Concrete Design Settings under the Calculation Sequence.
-
Stiffness modifiers or Cracked section inertia coefficient. Stiffness modifiers define a set of coefficients used to modify the in-plane axial and shear stiffnesses, as well as the out of plane bending, torsion and shear stiffnesses. The stiffness modifiers are available for planar element types: plate and shell, but are disabled for steel deck elements. For plane strain and membrane planar elements, there is a single stiffness matrix modifier available, known as the Cracked section inertia coefficient.
Stiffness modifiers or Cracked section inertia coefficient, depending on the planar element type
Stiffness modifiers can be defined in either Basic or Detailed mode:
- Basic mode. Each of the 8 modifiers defined in Basic mode will be applied to Young’s modulus on a direction and effort type. This means that some of the modifiers are affecting more than one term of the stiffness matrix.
Basic mode definition of Stiffness modifiers
-
Detailed mode. Each modifier corresponds to one specific term from the stiffness matrix, allowing for more precise adjustments.
Detailed mode definition of Stiffness modifiers
Note
Compute from basic. Convert coefficients from Basic to Detailed mode. This option is available when a single planar element is selected or when multiple planar elements with the same thickness, material properties, and basic stiffness coefficients are selected.
- Weight factor. Input a value to scale with the self-weight of the structural element.
To gain a clearer understanding of how this feature works, you can watch the video provided below:
Surface Element Stiffness Modifiers Video Tutorial
To learn more about using stiffness matrix modifiers for shell elements in Graitec Advance Design to model certain types of orthotropy, particularly CLT panels, please refer to this detailed article: Modeling CLT panels by using stiffness matrix modifiers
Cost estimations
- Settings by material: When enabled (default) the unit cost is considered as defined on Material.
- Unit costs: Field becomes enabled when "Settings by material" is disabled. Unit cost can be set to None, if is desired not to be accounted in overall cost estimation. If Unit prices Sets were previously defined, one of them can be chosen from the drop –down list. By clicking , the Unit Prices Manager dialog box will open, and Unit prices can be defined.
CO2 emission
- Settings by material: When enabled (default) the Carbon factors are considered as defined on Material.
- Carbon Factors: Field becomes enabled when "Settings by material" is disabled. Carbon factors can be set to None, if is desired not to be accounted in overall carbon emission estimation. If Carbon Factors Sets were previously defined, one of them can be chosen from the drop –down list. By clicking , the Carbon Factors Manager dialog box will open, and Carbon Factors can be defined.
- Allows you to modify the size of mesh elements on X and Y in the Results step, after completing the analysis.
- Side: defines the boundary conditions: Fixed, Pinned, Free, or Other. Any user-defined release type will be available in the releases list.
Properties of releases
- Definition: when selecting Other from the Side drop-down list, it allows a detailed definition of the boundary conditions on each edge of the element, using the Releases dialog box.
Releases Definition - step 1
To make it easier to understand, when you select a side in the grid, it will be highlighted in the image shown in the dialog.
Releases Definition - step 2
Releases Definition - step 3
Releases dialog box
The Releases type column lists all predefined options and custom releases defined by the user.
Clicking the icon next to the Releases type, Linear release type dialog box will open.
The same dialog box can be accessed from the ribbon: Manage Tab, Settings section:
Access to linear releases definition from the ribbon
Description of Linear release types dialog box
In the Linear release types dialog box, settings for predefined releases can be displayed and new releases can be defined.
Linear releases are always defined in the local coordinate system of the edge.
Definition and management of linear releases types
- Name is the combo box that:
- allows for selecting an existing type
- allows for entering new name by the user
- Save is the button that allows for saving currently selected release type.
- Delete is the button that allows for removing currently selected release type.
Note
The predefined release types (Fixed, Pinned, Free) cannot be edited/deleted.
- Tx, Ty, Tz – checkboxes for selecting releases for translational directions.
- Rx – checkbox for selecting a release for the rotational direction. Releasing Rx rotation will also release Ry and Rz.
- Degrees of freedom that have the checkbox unticked are considered to be fixed. For those directions, Stiffness and Nonlinearity fields are disabled.
- Stiffness – values for spring stiffnesses
- Nonlinearity – list with predefined types of a nonlinear law. It contains two entries:
- Compression only
- Tension only
- None.
Note
In the linear analysis, the stiffness of the release will be considered, and the nonlinearity setting will be ignored. For example, three releases with identical stiffness and nonlinearity set to Compression Only, Tension Only, and None, will show the same behavior during linear analysis.
In the nonlinear analysis, the stiffness of the release and nonlinearity will be considered. Compression/Tension only edge releases will be active only in the mesh nodes located on the edge where compression/tension occurs.
The meshing of the planar elements is performed according to the global mesh settings. The global mesh command is accessed from the main menu Options > Mesh. The meshing parameters for each planar element are defined using the properties window options.
-
Automatic: when enabled, the nodes are created at each intersection with the neighbored elements. When disabled, the element meshing is solved internally, without creating nodes with the intersecting elements.
-
Type: refers to the meshing style of the element considering the global mesh type. From the drop-down list select one of the following options:
-
"Complete": performs a complete meshing of the element by the global mesh algorithm, defined in the Mesh options dialog box.
-
"Triangulation": creates a triangular meshing with nodes on the sides of the planar element, using the global mesh algorithm.
Note
This option is useful for membrane elements that do not have in plane rigidity.
Mesh
- "None": the element is not meshed; the nodes are created at each vertex.
- Density: define the density of the mesh elements using the drop-down list options:
- "Global": the mesh element density is defined according to the global mesh settings.
- "Simplified": define the number of meshes on X and Y, in the "Simplified definition" fields.
- "Detailed": define the meshing for each side of the planar element in the "Detailed definition" fields:
- The number of mesh elements along the planar element side
- The size of a mesh element
- The spacing between mesh nodes along the planar element side
- Secondary size: define the size of meshes along the planar elements side considering the first defined size. The size of meshes will vary between the first and the second size values.
Tip: The simplified definition parameters values can be reset to 0 using the mesh options: from the main menu select Options > Mesh and click Reset mesh in the Mesh options dialog box (when the mesh type is Grid).
Tip: The detailed definition parameters values can be reset to 0 using the mesh options: from the main menu select Options > Mesh and click Reset mesh in the Mesh options dialog box (when the mesh type is Delaunay).
- Element size: define the size of a mesh element, in the "Element size field".
-
Input the system ID from which the planar element inherits the behaviour characteristics. For details, see Behaviour coefficient (seismic load case).
-
Define the planar element as a supporting element for snow and wind loads.
Tip: Click a section of the properties window. Notice the bottom area of the window; it displays a short description of the cell's current content.
Accessing the properties
-
In the Project Browser, expand the model Structure and select a planar element.
-
In the graphic area, select a planar element.
Note
When more planar elements are selected, the properties window displays their common properties.
FAQ (Frequently Asked Questions)
How can I display only finite element properties?
A: By selecting FE Properties from the Properties filter drop‑down list.
When are stiffness modifiers disabled automatically?
A: When Concrete inertia type is set to Auto.
Can releases include nonlinear behaviour?
A: Yes. Compression‑only or tension‑only behaviour can be defined for nonlinear analysis.