By default, Abaqus adjusts the position of slightly overclosed surfaces in a general contact domain as discussed in “Controlling initial contact status in Abaqus/Standard,” Section 31.2.4 of the Abaqus Analysis User's Manual. Contact initializations are used to modify the default behavior for contact surface adjustments. Each contact initialization definition contains a set of adjustment rules; the general contact definition specifies the surfaces to which each initialization definition is applied (see “Specifying and modifying contact property assignments for general contact,” Section 15.13.2).
Contact initializations are intended to correct small gaps or overclosures between surfaces. Specifying large initialization adjustments can lead to mesh distortion and increased computational cost for an analysis.
To create contact initializations:
From the main menu bar, select Interaction
Contact InitializationCreate.
The Edit Contact Intialization dialog box appears.
Enter a Name for the contact initialization definition.
You can specify the following techniques for treating Initial Overclosures between two surfaces:
Select Resolve with strain-free adjustments to adjust certain surfaces to be exactly touching at the beginning of the analysis without creating strain in the model. Only portions of surfaces that lie within the specified distance range are adjusted.
Select Treat as interference fits to resolve surface overclosures gradually over the course of the first step in the analysis; this technique creates strain in the model as the surfaces are displaced. Only portions of surfaces that lie within the specified overclosure distance range are adjusted using the interference fit.
Specify an overclosure distance range; nodes that are overclosed by a value less than the specified distance are adjusted using either strain-free adjustments or a gradual interference fit.
Select Analysis default to let Abaqus calculate a maximum overclosure adjustment distance based on the size of the underlying element facets on each surface.
Select Specify value to enter a maximum overclosure adjustment distance directly. If you enter a value that is smaller than the calculated analysis default for a surface, Abaqus uses the analysis default value for that surface.
Warning: If two surfaces (or portions of two surfaces) are initially overclosed by a distance greater than the specified adjustment value, contact between these severely overclosed surface regions is not enforced for the duration of the analysis; see “Controlling initial contact status in Abaqus/Standard,” Section 31.2.4 of the Abaqus Analysis User's Manual, for more information.
If you are initializing surfaces with strain-free adjustments, specify an opening distance range; nodes separated from the opposing surface by a value less than the specified distance are adjusted to lie exactly on the opposing surface.
Select Analysis default to ignore all open nodes during the initialization adjustments.
Select Specify value to enter a maximum opening adjustment distance directly.
If you want to reset the values in the dialog box to the default values, click Defaults at the bottom of the dialog box.
Click OK to save your contact initialization definition and to close the Edit Contact Initialization dialog box.
