Edit Contact dialog box
When a part interaction requires a different type of contact than the rest of the model, you can either:
- Define the unique contact pairs manually, or
- Generate contacts automatically and then override the settings for the appropriate contact pairs.
To access this dialog, from the Contacts Manager click 
Edit associated with the Contact Set you want to modify.
General Options
| Dialog widget | Explanation |
|---|---|
| Primary Body and Secondary Body - Manual contact sets only |
- Unsymmetric Penetration Type:contact interaction occurs between the nodes (mesh points) on the Secondary Body and the faces of the Primary Body. In other words, nodes on the Secondary Body are not allowed to penetrate the surface of the Primary Body. However, nodes on the Primary Body may penetrate faces of the Secondary Body. - Symmetric Penetration Type: the nodes on both bodies are prevented from penetrating the faces of the other body. Therefore, which body you choose as primary and which as secondary is unimportant. |
| Selection Set 1 - Manual contact sets only |
Surfaces or edges on the Primary body that participate in the contact set. Note: Once you pick the first entity, the remaining entities must be the same type. In other words, all selected entities must be edges, or all must be faces. (Either type is supported, but you cannot mix them.) |
| Selection Set 2 - Manual contact sets only |
Surfaces or edges on the Secondary body that participate in contact. Note: If you chose one or more participating edges of the Primary Body (in the preceding step), you can only choose edges of the Secondary Body. With one or more faces of the Primary Body selected, you can choose either faces or edges of the Secondary Body. However, once you pick the first Secondary body entity, the remaining ones must be the same type. In other words, all selected entities must be edges, or all must be faces. (Either type is supported, but you cannot mix them.) |
| Contact Type | Contact types are designated by a drop-down list. |
| Penetration Type: | The Penetration Types are designated using a drop-down list. |
| Automatic Max. Activation Distance | The software chooses the contact activation distance (see next bullet) based on the geometry and mesh size. |
| Max. Activation Distance | The maximum distance between participating entities at which contact should be enforced. You can manually enter a value, choose a previously specified value (from the drop-down list), or measure a distance on the model (by choosing Measure from the drop-down list). This parameter is useful when parts are not drawn coincident to each other, and a small gap is present. This value can also limit the number of contact interactions and therefore decrease the solution time. Choose a small enough value to prevent unnecessary, and possibly conflicting, contact interactions. |
| Thermal Conductance - Thermal and Thermal Stress studies only. |
Specify the heat flow across the contact interface, per unit area, per degree. The units are: - Metric (SI): W/(m^2 K). The Watt (W) is a unit of power equivalent to one Joule (J) of energy per second. - English (in): BTU/(hr.ft2.oF). The English length unit for thermal conductance is feet, even though the length unit for the English (in) system is inches. Note: You cannot customize the Thermal Conductance units. This input field is blank by default, and infinite thermal conductance is assumed (no resistance to heat flow). With no thermal resistance, the temperature results are identical on both contact faces. When you specify a value, the results show a temperature difference across contact boundaries due to the limited thermal conductance. |
| Coefficient of Static Friction - Contact Type = Separation, only |
If you do not specify a value, the contact interaction is frictionless. That is, there is no resistive force in the tangential direction when two faces or an edge and face slide along each other. If you enter a value, sliding is resisted by a tangential force equal to the specified coefficient times the normal force. For example, if the normal force at the contact face is 500 kg, and the coefficient of static friction is 0.2, then the tangential friction force is 500 kg * 0.2, or 100 kg. |
Advanced Options
The advanced options are available for all contact types except Free. A fairly in-depth understanding of Nastran contact is required to use these options. They allow additional information to be input to further refine the contact behavior. Full details on the advanced parameters can be found in the BSCONP page of the Autodesk Nastran Reference Guide.