Surface-to-surface contact interactions describe contact between two deformable surfaces or between a deformable surface and a rigid surface. Self-contact interactions describe contact between different areas on a single surface. For detailed instructions on creating these types of interactions, see “Defining surface-to-surface contact,” Section 15.12.1, and “Defining self-contact,” Section 15.12.2. For more information, see “Defining contact pairs in ABAQUS/Standard,” Section 29.2.1 of the ABAQUS Analysis User's Manual, and “Defining contact pairs in ABAQUS/Explicit,” Section 29.4.1 of the ABAQUS Analysis User's Manual.

If your model includes complex geometries and numerous contact interactions, you may want to customize the variables that control the contact algorithms to obtain cost-effective solutions. These controls are intended for advanced users and should be used with great care. For more information, see “Contact controls editors,” Section 15.8.4.

General contact interactions allow you to define contact between many or all regions of the model with a single interaction. Typically, general contact interactions are defined for an all-inclusive surface that contains all exterior faces, shell perimeter edges, edges based on beams and trusses, and analytical rigid surfaces in the model. To refine the contact domain, you can include or exclude specific surface pairs. Surfaces used in general contact interactions can span many disconnected regions of the model. Attributes, such as contact properties, surface properties, and contact formulation, are assigned as part of the contact interaction definition but independently of the contact domain definition, which allows you to use one set of surfaces for the domain definition and another set of surfaces for the attribute assignments. For detailed instructions on creating this type of interaction, see “Defining general contact,” Section 15.12.5.

General contact interactions and surface-to-surface or self-contact interactions can be used together in the same analysis. Only one general contact interaction can be active in a step during an analysis.

For more information, see “Contact interaction analysis: overview,” Section 29.1.1 of the ABAQUS Analysis User's Manual, and “Defining general contact interactions,” Section 29.3.1 of the ABAQUS Analysis User's Manual. The assignment of a penalty stiffness scale factor is not supported in ABAQUS/CAE. In addition, node-based surfaces cannot be used in a general contact interaction in ABAQUS/CAE.

Elastic foundations allow you to model the stiffness effects of a distributed support on a surface without actually modeling the details of the support. You can create elastic foundation interactions only in the initial step. Once an elastic foundation is activated, you cannot deactivate it in later analysis steps. For detailed instructions on creating this type of interaction, see “Defining foundations,” Section 15.12.11. For more information, see “Element foundations,” Section 2.2.2 of the ABAQUS Analysis User's Manual.

Film condition interactions define heating or cooling due to convection by surrounding fluids. Two types of film condition interaction are available in ABAQUS/CAE: surface film conditions define convection from model surfaces, and concentrated film conditions define convection from nodes or vertices. You can define film condition interactions only during a heat transfer, fully coupled thermal-stress, or coupled thermal-electrical step. For detailed instructions on defining these types of interactions, see “Defining a surface film condition interaction,” Section 15.12.12, and “Defining a concentrated film condition interaction,” Section 15.12.13, respectively. For more information, see “Thermal loads,” Section 27.4.4 of the ABAQUS Analysis User's Manual.

Radiation interactions describe heat transfer to a nonreflecting environment due to radiation. Two types of radiation interactions are available in ABAQUS/CAE: surface radiation interactions describe heat transfer with a nonconcave surface, and concentrated radiation interactions describe radiation from nodes or vertices. You can define radiation interactions only during a heat transfer, fully coupled thermal-stress, or coupled thermal-electrical step. For detailed instructions on creating these types of interactions, see “Defining a surface radiative interaction,” Section 15.12.14, and “Defining a concentrated radiative interaction,” Section 15.12.15, respectively. For more information, see “Thermal loads,” Section 27.4.4 of the ABAQUS Analysis User's Manual.

Incident wave interactions model incident wave loading due to external acoustic wave sources. For detailed instructions on creating this type of interaction, see “Defining incident waves,” Section 15.12.10. For more information, see “Acoustic loads,” Section 27.4.5 of the ABAQUS Analysis User's Manual.

An acoustic impedance specifies the relationship between the pressure of an acoustic medium and the normal motion at an acoustic-structural interface. For detailed instructions on creating this type of interaction, see “Defining acoustic impedance,” Section 15.12.9. For more information, see “Acoustic loads,” Section 27.4.5 of the ABAQUS Analysis User's Manual.

An actuator/sensor interaction models a combination of sensors and actuators and, therefore, allows for modeling control system components. Currently, this type of interaction allows sensing and actuation at just one point. For detailed instructions on creating this type of interaction, see “Defining an actuator/sensor interaction,” Section 15.12.16.

The interaction definition and its optional associated property are used to define the basic aspects of the interaction, but the user must provide user subroutine UEL to supply the specific formulae for how actuation depends on sensor readings. You specify the name of the file containing the user subroutine when you create the analysis job in the Job module.

Actuator/sensor interactions are available only for ABAQUS/Standard analyses. For more information, see “User subroutines and utilities,” Section 13.2 of the ABAQUS Analysis User's Manual.