You can use contact initializations to determine how general contact surfaces
are adjusted automatically before the simulation starts.
Contact initializations
are intended to correct small gaps or overclosures between surfaces. Defining contact
initialization simplifies your simulation by making minor adjustments to the initial position of
the components. The adjustments move components so that they are touching and no residual strain
is introduced before the simulation begins.
The default contact initialization options apply
to the majority of simulation cases. Therefore, in most cases, you only need to create the
contact initialization feature.
Warning:
Specifying large initialization
adjustments can lead to mesh distortion and increased computational cost for the
simulation.
From the Interactions section of the action bar,
click Contact Initialization.
Optional:
Enter a descriptive
Name.
Optional:
If you intend to use the small-sliding formulation together with general contact for
static and static perturbation steps, select Small-sliding
formulation.
Note:
The small-sliding formulation is not supported for explicit dynamic steps.
From the Initial Overclosures options, select one of the
following overclosure methods to adjust the secondary surfaces:
Option
Description
Resolve openings/overclosures
Treats overclosed surfaces as though they are in contact at the start of the
simulation. Surfaces are either adjusted or the required offsets to adjust them are
recorded so that they do not introduce strains.
Treat as interference fits
Resolves surface overclosures gradually over the course of the first step in the
simulation. This technique creates strain in the model as the surfaces move. Only
portions of secondary surfaces that lie within the specified overclosure distance
range are adjusted using the interference fit.
Specify clearance distance
Adjusts secondary surfaces to separate them by the value you specify at the
beginning of the simulation without creating strain in the model. Only portions of
secondary surfaces that lie within the specified distance range are adjusted.
If you chose the
Resolve
openings/overclosures overclosure method, select one of
the following:
Option
Description
Make strain-free adjustments
Adjusts overclosed secondary surfaces to be exactly touching at the beginning of
the simulation without creating strain in the model.
Capture offsets
Prevents overclosed nodes on the secondary surface from being moved (adjusted)
back to the main surface. Records the offset distances for underclosed secondary
surface nodes and acts as if they are in contact during the simulation.
Note:
You can select Capture offsets only
if you selected Small-sliding formulation.
If you chose the Treat as interference fits overclosure method,
select Specify interference distance to establish a uniform
overclosure distance before resolving the interference fit.
The app adjusts portions of secondary surfaces that lie within the specified distance range
(both overclosures and openings) to be overclosed by the specified amount. The adjustments
occur at the beginning of the simulation without creating strain in the model. The
subsequent interference fit resolution during the first step in the simulation creates
strain in the model.
If you chose the Specify clearance distance overclosure method,
customize the clearance distance beyond which the app
considers two secondary surfaces as separate and not creating strain in the
simulation.
Expand the Adjustments section, and do the following to specify
a threshold distance for overclosures and initial openings:
From the Ignore overclosures greater than options, select
one of the following:
Option
Description
Analysis default
Calculates a maximum overclosure adjustment distance (based on the size
of the underlying element facets on each surface) automatically.
Specify value
Allows you to specify a maximum overclosure adjustment distance
directly.
If you enter a value that is smaller than the calculated
default for a surface, the analysis default value for that surface is
used.
The app
adjusts secondary nodes that are overclosed by a value less than the specified
distance using either strain-free adjustments or a gradual interference fit.
From the Ignore initial openings greater than options,
select one of the following:
Option
Description
Analysis default
Ignores all open nodes during the initialization adjustments.
Specify value
Allows you to specify a maximum opening adjustment distance
directly.
The app
adjusts secondary nodes separated from the opposing surface by a value less than the
specified distance using strain-free adjustments.
.