Local Interactions PropertyManager

You can use the Local Interactions PropertyManager to define interactions between sets of geometric entities of solids, shells, and beams. Local interactions settings override component-level interactions.

Interaction

Manually select local interactions Select pairs of geometric entities to apply local interaction conditions.
Automatically find local interactions Activates the interaction detection tool to find interaction sets for touching faces or non-touching faces within a specified clearance.
The interaction detection tool might not find all the interaction sets you expect. Review the tentative interaction sets under Results and accept only the local interactions required for your analysis.

Type

Select an interaction type from the list of available types: Contact, Bonded, Free, Shrink Fit, or Virtual Wall.

Faces, Edges, Vertices, for Set 1 Select geometric entities for Set 1.
  • To bond beam joints, select Joints .
  • To bond beams to solid or shell faces that act as stiffeners, select Beams .
Faces for Set 2 Select faces for Set 2.

For a Virtual Wall interaction type, select a Target Plane .

Entities in the Set 1 and Set 2 might belong to the same component, body, or shell.
Faces, Edges for Set 2 Available for the Bonded interaction type.
The following selection pairs are valid for shells and sheet metal bodies when applying a bonded interaction set:
Set 1 Set 2
Face Face
Edge Edge, Face
Vertex Vertex, Edge, Face
Swap interaction faces

Switches the geometry selections between the Set 1 and Set 2 sets to resolve convergence issues during a simulation.
  Switch source and target entities automatically for better result When this option is selected, the preprocessor assigns the source and target entities for bonded local interactions based on the average area per node. A surface with the smaller average nodal area is acting as a source.

When this option is cleared, the entities selected for Set 1 are acting as source, and the entities selected for Set 2 are acting as target.

This option is available for bonded local interactions only.
  Self-Contact Available for static studies (large displacement option) and nonlinear studies that have Contact interactions.

Detects entities of a body that might come into contact with each other during the simulation and applies a contact condition to prevent interference.

For example, if you select Face 1 for Set 1, the same face is considered as the source and target entity for a contact set.

You can select multiple faces for Set 1, for example Face 1, Face 2, and Face 3. Self-contact detection is considered between pairs with the same source and target entity: Face 1 with Face 1, Face 2 with Face 2 , and Face 3 with Face 3. To detect possible contact between Face 1 and Face 2, create a separate contact set.

Self-contact detection is not available for 2D Planar Simplification nonlinear analysis.

Options

(Available when you select Automatically find local interactions.)

Find faces Detects interaction sets between faces of selected components that meet the specified criteria.
Find shell edge - solid/shell face pairs Detects interaction sets between shell edges and solid or shell faces.

Components

(Available when you select Automatically find local interactions.)
Select Components or Bodies Select the components or bodies to detect possible interaction sets. To select the entire assembly, use the flyout FeatureManager design tree.
Find contacts with the rest of the assembly Select a single component or body to detect possible interaction sets between neighboring components.

Results

  Tentative Local Interactions Lists the tentative interaction sets that are detected by the interaction detection tool.
  Type Specifies the interaction type for the selected tentative interaction sets.
The available interaction types depend on the active study type.
  Create local interactions Accepts the tentative interaction sets you select from the list.
Delete local interactions Deletes the selected tentative interaction sets from the list.
  Transparent view Makes the faces of the components that have tentative interaction sets transparent. This makes it easier to see the local interaction sets.

Interfering Faces

Lists the interfering pairs of shell and solid faces. Select an interfering set to highlight the interfering faces in the graphics area.

Properties

Gap range for bonding You can let the program calculate the maximum clearance that qualifies the selected geometric entities for a local bonded interaction or enter a user-defined maximum clearance.

Automatic

The program calculates the maximum clearance that qualifies the selected geometric entities for a local bonded interaction. The equation that calculates the suggested clearance is given below. The automatic option applies to Static, Frequency, and Buckling studies.

Show the suggested gap range

Shows the value of the suggested maximum clearance for the selected entities of the local interaction set. Entities that have clearances larger than this threshold are not bonded at a local-level.

User defined

Enter the clearance for Maximum Gap that allows geometric entities to qualify for local bonding interactions. Entities that have clearances larger than this threshold are not bonded at a local-level. User-defined clearances overwrite automatic clearances.


  • gth = suggested clearance of parts to qualify for local bonded interaction
  • gmin = actual minimum distance between parts that belong to the local interaction set
  • LMaxBBDimPart (I) = Maximum Bounding Box Dimension of Part (I)
  • N = number of parts that belong to the local interaction set
Enter a very small value rather than zero for maximum clearance to ensure bonding of curved, coincident geometry. Before you run the analysis, you can verify the areas of interactions (such as bonded, contact, and free) defined by the global-level and local-level interaction settings with the Interaction Viewer PropertyManager.
Gap range to consider contact Specifies the clearance that allows geometric entities to qualify for contact. Entities that have clearances larger than this threshold do not qualify for contact at a local-level.

The default value specified in Default Options > Interactions is 10% of the characteristic length of the model.
Stabilize the area if the gap is Applies a small stiffness to the qualified areas so the solver can overcome instability issues and start the simulation. SOLIDWORKS Simulation applies contact stabilization to components that have an initial clearance within a range of 1% of the model's characteristic length.

You can customize the allowable clearances to better fit your models.
Coefficient of friction Specifies the friction coefficient for use with:
  • Contact interactions (static, nonlinear, and drop test studies)
  • Shrink Fit interactions (static and nonlinear studies)
  • Virtual Wall interactions
You can specify values from 0 to 1.0. This local value overrides the global friction coefficient that you specify in the Default Options > Interaction dialog box.
Contact offset

When selected, the pair of entities is considered to be initially touching despite the initial gap between them. The options below set a limit to the initial gap.

Contact forces develop when the entities tend to move closer to each other during a simulation.

  • If gap is less than. Creates the contact interaction between entities that have clearances less than this threshold value. Entities with clearances larger than this threshold are considered non-touching and contact is not enforced.
  • Unlimited gap distance. Creates the contact interaction between entities regardless of the size of the clearance between them in the undeformed state of the model.
Contact offset applies to Contact and Virtual Wall interactions between entities that mesh with a solid mesh.
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Thermal Resistance

Defines the thermal resistance for thermal studies.

Units

Selects the unit system.

Total

Specifies the value of the total thermal resistance between the Set 1 and Set 2 entities.

Distributed

Specifies the value of the resistance per unit contact area.

Wall Type

(Available only for a Virtual Wall interaction.)

Rigid Specifies the wall type as rigid.
Flexible Specifies the wall type as flexible.

Wall Stiffness

(Available only for a Virtual Wall interaction.)

Specify parameters for a Flexible wall type.

Units Selects the unit system of the wall stiffness values.
Axial Stiffness Specifies the value of the wall axial stiffness.
Tangential Stiffness Specifies the value of the wall shear stiffness.

Advanced

Bonding formulation Specifies the local bonding formulation for bodies that mesh independently.
  • Surface to surface. This default option is more accurate, but slower. For a 2D Simplification study, the solver applies an edge-to-edge bonding.
  • Node to surface. Select this option if you run into performance issues when solving models with complicated contact surfaces. For a 2D simplification analysis, the program applies a node-to-edge bonding.
Contact formulation Specifies the local contact formulation. Both contact formulations prevent interference between the Set 1 and Set 2 geometric entities, but allow them to move away from each other.
  • Surface to surface. This default option is more accurate but slower. See also topic Surface to Surface Contact.
  • Node to surface. Although Surface to Surface contact is more accurate in general, the Node to Surface option gives better results if the contact area between the two faces becomes very small, or reduces to a line or a point.

    See also topic Node to Surface Contact.

    For nonlinear studies, the node-to-surface contact formulation is supported for the Direct Sparse and Intel Direct Sparse solvers only. When you select the FFEPlus or the Large problem Direct Sparse solver, the solver switches automatically to the supported surface to surface contact formulation.