30.3.1 Electrical contact properties

Product: ABAQUS/Standard

References

Overview

Electrical conduction between two bodies:

is proportional to the difference in electric potentials across the interface;
is a function of the clearance between the surfaces;
can be a function of surface temperatures and/or predefined field variables on the surfaces; and
can generate heat at the interface.

See “Coupled thermal-electrical analysis,” Section 6.6.2, for details on coupled thermal-electrical analyses.

Including gap electrical conductance properties in a contact property definition

You can include electrical conductance properties in a contact property definition for surface-based contact.

Input File Usage:	Use both of the following options:
	SURFACE INTERACTION, NAME=name* *GAP ELECTRICAL CONDUCTANCE

Modeling electrical conductance between surfaces

ABAQUS/Standard models the electrical current flowing between two surfaces as

where J is the electrical current density flowing across the interface from point A on one surface to point B on the other,

and

are the electrical potentials on opposite points on the surfaces, and

is the gap electrical conductance. Point A corresponds to a node on the slave surface of the contact pair. Point B is the point of the master surface in contact with point A.

You can provide the electrical conductance directly or in user subroutine GAPELECTR.

Defining σ_g directly

When the gap electrical conductance is defined directly, ABAQUS/Standard assumes that

where

is the average of the surface temperatures at A and B,

is the clearance between A and B, and

is the average of any predefined field variables at A and B.

Defining gap electrical conductance to be a function of predefined field variables

The gap electrical conductance can be dependent on any number of predefined field variables, . By default, it is assumed that the electrical conductivity depends only on the surface separation and, possibly, on the average interface temperature.

Input File Usage:

*GAP ELECTRICAL CONDUCTANCE, DEPENDENCIES=n

Defining σ_g using user subroutine `GAPELECTR`

When is defined in user subroutine GAPELECTR, there is greater flexibility in specifying the dependencies of than there is using direct tabular input. For example, it is no longer necessary to define as a function of the average of the two surfaces' temperatures or field variables:

Input File Usage:

*GAP ELECTRICAL CONDUCTANCE, USER

Modeling heat generated by electrical conduction between surfaces

ABAQUS/Standard can include the effect of heat generated by electrical conduction between surfaces in a coupled thermal-electrical analysis. By default, all dissipated electrical energy is converted to heat and distributed equally between the two surfaces. You can modify the fraction of electrical energy that is released as heat and the distribution between the two surfaces; see “Modeling heat generated by nonthermal surface interactions” in “Thermal contact properties,” Section 30.2.1, for details.

Surface-based output variables for electrical contact property models

ABAQUS/Standard provides the following output variables related to the electrical interaction of surfaces:

ECD	Electric current per unit area leaving slave surface.

ECDA	ECD multiplied by the area associated with the slave node.

ECDT	Time integrated ECD.

ECDTA

Time integrated ECDA.

The values of these variables are always given at the nodes of the slave surface. They can be requested as surface output to the data, results, or output database files (see “Surface output from ABAQUS/Standard” in “Output to the data and results files,” Section 4.1.2, and “Surface output” in “Output to the output database,” Section 4.1.3, for details).

Contour plots of these variables can also be displayed in the Visualization module of ABAQUS/CAE (ABAQUS/Viewer).