Guidelines on Studies with Interaction Conditions


The following are general guidelines for specifying interaction conditions:

  • Check for interference between components before meshing. To detect interference in an assembly, click Tools > Evaluate > Interference Detection. Interference is allowed only when applying the Shrink Fit interaction type. The Treat coincidence as interference option allows you to detect touching areas.
  • Use the Local Interactions PropertyManager to define interactions between solids, shells, and beams.
  • Select Automatically find local interactions (Local Interactions PropertyManager) to detect interactions for components that are touching or are not touching, but are within a certain clearance.
  • Specify global, component, and local interactions efficiently to define the actual behavior of components for a successful simulation. Assign the most common interaction type globally, and then define component-level and local-level interaction conditions as required.
  • Local interactions settings override component-level interactions, while component-level interactions override global-level interactions.
  • Remesh the study after editing or defining contact conditions.


  • Bonding ensures the continuity of components and the transfer of applied loads between two entities. You can bond a face or an edge to any other face or edge. The mesh at the touching boundaries of the bonded entities does not have to be continuous.
  • For assembly components that share common mesh nodes but failed to bond, select Remesh failed parts independently (Default Options - Mesh dialog box).
  • SOLIDWORKS Simulation enforces bonded 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.
  • When bonding solid faces through the global contact condition, select Enforce common nodes between touching boundaries (Default Options - Interactions) to generate a continuous mesh on the touching boundaries.

  • In cases of bonding between a sheet metal and other surfaces (solids or shells), a gap exists between the mid-surface mesh and the surface geometry because of the shell thickness. An algorithm for the Surface to surface bonding formulation for Linear static, Frequency, and Buckling studies detects the rigid body motion caused by the gap, and ensures the accuracy of the solution. For the Node to surface simplified bonding formulation and for all bonding types in Nonlinear studies, such enhancement is not yet implemented.
Consider the following model:

  • A global bonded interaction bonds the whole circular face of the cylinder to the plate.
  • If the cylinder is connected to the plate by welding its edge only, then specify the global interaction to Free, and bond the face of the plate to the edge of the cylinder by defining a local interaction set.
  • If a small clearance exists, you can specify the appropriate Gap range for bonding (Local Interactions PropertyManager) to bond the cylinder's face or edges to the plate.

Static and Nonlinear Studies

  • Contact is a common source of nonlinearity. Although nonlinear studies are preferred for solving contact problems, you can use static studies to solve contact problems with small and large displacements.
  • The properties dialog box of static and nonlinear studies provides an option to use large displacements. Use the small displacement formulation only if the expected motions are small and the parts are independently stable in directions other than the primary contact direction.
    SOLIDWORKS Simulation automatically detects when large displacements occur and prompts you to activate the large displacement flag. Select Yes to rerun the simulation with the large displacement option. Select No to run the simulation with the small displacement formulation.
    When you use static studies with the large displacement option to solve contact problems, the results are available only at the last solution step. In nonlinear studies, results are available at every solution step.
  • Use Shrink Fit in the Local Interactions PropertyManager to define a shrink fit interaction condition between initially interfering components.
  • In general, the Surface to surface contact formulation is more accurate than the Node to surface contact option. However, it takes longer to solve and may not converge when the contact area becomes too small. In such cases, use the Node to surface option.
  • The Node to node contact formulation is no longer available. When you open models with legacy node-to-node contact definitions, SOLIDWORKS Simulation converts them to Node to surface contact during the analysis.

Thermal Studies

  • The Bonded, Thermal resistance, and Insulated interaction conditions are available. Free faces (faces without any boundary conditions) are insulated. A free face is thermally similar to a face with a zero temperature gradient in the normal direction. Faces of thermal symmetry can be modeled as free faces. Heat can flow parallel to the face but cannot flow normal to it.
  • Use the Surface to surface formulation to simulate thermal resistance.

Buckling Studies

Only the Bonded and Free interaction options are available.

Frequency Studies

Only the Bonded and Free interaction options are available. Use caution when specifying the Free option and interpreting results associated with it as the parts are considered disjointed.

Linear Dynamic Studies

The Bonded and Free interaction options are available for all linear dynamic study types.

Drop Test Studies

The Bonded, Free, and Contact options are available. Only the Node to surface contact formulation is available.