Contact Tool Guides and Options

Contact Tool Guides

The following tool guides are available:

Select secondary surface When you select one or more faces for a contact, any additional faces that contact those selected faces will also be defined as the contact type you specify. If you want to narrow it down to a specific pairing of faces, select the Select secondary surface tool before selecting the second face. You can also use Alt-click.

Contact Types

The following contact types are available:

Bonded Select Bonded to specify that no sliding or separation between faces or edges is allowed. Think of the region as glued. This type of contact allows for a linear solution since the contact length/area will not change during the application of the load. Any gaps will be closed and any initial penetration will be ignored.
Sliding Select Sliding to define contact where the surfaces can freely slide in the tangential direction relative to each other.
Excluded Select Excluded if the bodies are to ignore each other.

Bonded Contact Tool Options

The following tool options are available for the Bonded contact type in a structural analysis:

Strength limits

Select to specify the Shear and Tensile stress limits of the bond during service conditions if the contacts are not perfectly bonded.

After solving, you can assess your contacts in the Connection Assessment Tool. This tool cycles through the connections and shows whether they pass or fail the factor of safety based on these specified shear and tensile limit values.

Shear stress Specify the shear stress limit of the bond during service conditions.  This is used when monitoring the factor of safety of the contact. Contact failure is not simulated.
Tensile stress Specify the tensile stress limit of the bond during service conditions.  This is used when monitoring the factor of safety of the contact. Contact failure is not simulated.
Specify thermal conductance

In a structural-thermal simulation, enable to specify the conductive heat transfer between contact surfaces. You can specify the thermal conductance as a value, or you can specify a material and material thickness, which Discovery then uses to compute the thermal conductance (material conductivity/thickness). If thermal conductance is not switched on, heat is transferred between the two faces as if there was perfect conduction.

If contact occurs, a small value of thermal contact conductance yields a measured amount of imperfect contact and a temperature discontinuity across the contact surfaces. A small thermal contact conductance can also be used to represent a thin layer of material with a different conductivity, such as a gasket.

For large values of thermal contact conductance, the resulting temperature discontinuity tends to vanish and perfect thermal contact is approached. With a zero value, however, the solver assumes that no heat is transferred across the contacting surfaces.

Note: While Discovery can solve with a value of 0, which specifies no heat transfer between the faces, a project with a 0 value for thermal conductance is invalid when exported to Workbench. You must then replace zero conductance with some small value.

Sliding Contact Tool Options

The following tool options are available for a sliding contact type:

Idealized

Allows frictionless sliding but no separation, which enforces linear behavior.
Frictional

Allows for sliding with separation. You can then enter a Friction coefficient.

Note: Friction coefficient values are ignored in the Explore stage, but separation is allowed.
Friction coefficient The coefficient of friction. Entering zero results in frictionless sliding.
Adjust gap or overlap Defines how the contact interface is treated with Adjust gap or overlap. Select Make just touching to direct that any initial gaps are closed and any initial penetration is ignored, creating an initial stress-free state. Or you can model true contact gap/penetration plus the offset value you specify with Define specific offset.
Stiffness factor Modifies the default factor for Stiffness factor to control the amount of penetration between contact and target surfaces.
Detection radius factor Modifies the default factor for Detection radius factor to specify the radius of contact detection to be used during solve in order to obtain a good convergence.