Gasket elements are specialized solid elements designed to model the through-thickness behavior of gaskets as they create a seal between structural components. Gasket elements can be used only in a Nonlinear Structural Analysis case. Creating and using gaskets in Abaqus for CATIA V5 requires a combination of gasket material properties, gasket element assignments, and a gasket property definition. Gasket material properties are discussed in Specifying Abaqus Material Properties, and the element assignment is described in Modifying Global Element Assignments and Modifying Local Element Assignments. The gasket property extends the 3D Property definition to include the following information:
Stabilization Stiffness
Gasket elements are intended to be supported by the structural components that they are sealing. When gaskets extend beyond these components, the resulting partially supported or unsupported areas can cause problems in the analysis. Stabilization stiffness is a very small artificial stiffness value applied to make the gasket self-supporting and prevent these analysis problems.
Initial Thickness
The default initial thickness is calculated between the top and bottom nodes of the gasket elements. If the gasket is intended to have a constant thickness, it may be more accurate to specify the thickness value directly.
Initial Gap
Many gaskets have a complex surface geometry. The initial gap defines the distance that a gasket must be compressed before the surface creates pressure on the surrounding structural components.
Initial Void
When gaskets are composed of several layers of material, voids often exist between the layers until they are compressed. The initial void is used by Abaqus only for calculating thermal strain and creep strain.
This task shows you how to use gasket properties.
Create a solid part in CATIA V5 along with an axis system that you will use to define the material orientation.
Apply a material including Abaqus gasket material definitions to the part.
Mesh the part using solid linear or solid parabolic elements.
Select Start>Analysis & Simulation>Nonlinear Structural Analysis from the menu bar to enter the Nonlinear Structural Analysis workbench. If necessary, set an empty analysis case or an analysis case that contains structural analysis procedures to be the current case.
Create a 3D property, and select the gasket part as the support.
Create a Gasket Property.
From the Gasket Property dialog box that appears, do the following:
Use the default Stabilization Stiffness, or specify a value.
The default value is on the order of 10–9 times the initial compressive stiffness; it is appropriate for most analyses.
Use the default Initial Thickness as measured between the nodal coordinates, or specify a value.
Specify an Initial Gap to be closed before the gasket surface applies pressure to the surrounding components.
Specify an Initial Void to be closed before the internal gasket layers are in contact.
Click OK to close the Gasket Property dialog box.
Use the global or local element assignment tools to assign gasket elements to the mesh. See Modifying Global Element Assignments and Modifying Local Element Assignments for more information.