Default Options - Interactions

Specifies the default settings for global-level interactions for new simulation studies.

To specify the settings for global-level interactions for new studies:

  • Click Simulation > Options. On the Default Options tab, click Interaction.

Global Interaction Type

Simulation enforces bonded or contact interactions to qualified geometric entities that are not initially touching based on specified clearances. These settings ensure that you can run simulations, even for models with slightly imperfect geometries. You can customize the default clearances to better fit your models.

The global settings for interactions for qualified geometric entities propagate to the component interaction and local interaction definitions.

Linear static study Specifies the global interaction type for linear static studies: Bonded, Contact, or Free.

Properties

Gap range for bonding: Specifies the maximum clearance that allows geometric entities to qualify for bonding interactions. The default value is 0.01 % of the characteristic length of the model. Geometric entities that have clearances larger than this threshold are not bonded on a global-level.
Include shell edge-solid face/shell face and edge pairs (slower) Creates edge-to-edge bonded contact sets for pairs of edges located within the allowable clearance for bonding.
The valid pairs of edges of shells or sheet metal bodies that qualify for bonding are:
  • Straight, parallel, and non-interfering shell edges (or almost parallel within one degree of tolerance).
  • Circular edges that have the same radius, are concentric, and do not interfere.
  • Shell edges (straight or arc) bonded to a solid or shell face (planar or cylindrical).
Gap range to consider contact: Specifies the maximum clearance that allows geometric entities to qualify for contact. The default value 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. The software applies contact stabilization to geometries that have an initial clearance within a threshold value of 1% of the model's characteristic length.
Coefficient of friction Specifies the coefficient of static friction for global contact conditions. The allowable range for the friction coefficient is 0 to 1.0.

The static friction forces are calculated by multiplying the normal forces generated at the locations that come into contact by the given coefficient of friction. The direction of the friction force is opposite to the direction of motion.

For local contact conditions, you specify a friction coefficient in the Local Interactions PropertyManager.

Advanced

Enforce common nodes between touching boundaries Enforces mesh continuity on the touching boundaries of different bodies for assemblies and multibody parts. The components that are touching mesh as one body.
Contact formulation Specifies the global contact formulation. Both contact formulations prevent interference between the source and target 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.
Bonding formulation Specifies the global 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 penalty stiffness scale factor Specifies a scale factor for the penalty stiffness for contact to use in linear static studies.

To reach a precise solution for linear static studies with contact interactions, use 1.0 for the penalty stiffness factor.

To assess design iterations and the overall behavior of a model, specify a value lower than 1.0 to obtain an approximate solution faster.