GAPELECTR

User subroutine to define electrical conductance between surfaces in a coupled thermal-electrical or a coupled thermal-electrical-structural analysis.

User subroutine GAPELECTR:

  • assumes that the electrical current flowing between the interface surfaces is modeled as J=σg⁢(φA-φB), where J is the electrical current density flowing across the interface from point A (the slave surface) to point B (the master surface), φA and φB are the electrical potential on opposite points of the surfaces, and σg is the surface electrical conductance;

  • is used to define σg, providing much greater flexibility than direct gap electrical conductance definition in specifying the dependencies of σg (for instance, it is not necessary to define the gap electrical conductance as a function of the average of the two surfaces' temperatures and/or field variables);

  • will be called at the slave nodes of a contact pair (About contact pairs in Abaqus/Standard) for which the gap electrical conductance is defined in a user subroutine; and

  • ignores any dependencies or data specified for the gap electrical conductance outside the user subroutine.

The following topics are discussed:

Related Topics
In Other Guides
Electrical contact properties
*GAP ELECTRICAL CONDUCTANCE

ProductsAbaqus/Standard

User subroutine interface

      SUBROUTINE GAPELECTR(SIGMA,D,TEMP,PREDEF,TIME,CINAME,
     1 SLNAME,MSNAME,COORDS,NODE,NPRED,KSTEP,KINC)
C
      INCLUDE 'ABA_PARAM.INC'
C
      CHARACTER*80 CINAME,SLNAME,MSNAME
C
      DIMENSION SIGMA(5),D(2),TEMP(2),PREDEF(2,*),TIME(2),
     1 COORDS(2,3)

      user coding to define SIGMA(1) -- SIGMA(5)

      RETURN
      END

Variables to be defined

SIGMA(1)

Gap electrical conductance, σg.

SIGMA(2)

∂⁡σg/∂⁡θA, derivative of the gap electrical conductance with respect to the temperature of point A. If the gap electrical conductance is not a function of θA, SIGMA(2) = 0.0.

SIGMA(3)

∂⁡σg/∂⁡θB, derivative of the gap electrical conductance with respect to the temperature of point B. If the gap electrical conductance is not a function of θB, SIGMA(3) = 0.0.

SIGMA(4)

∂⁡σg/∂⁡d, derivative of the gap electrical conductance with respect to the clearance between the bodies. If the gap electrical conductance is not a function of gap clearance, SIGMA(4)= 0.0. This variable needs to be defined only for a fully coupled thermal-electrical-structural analysis.

SIGMA(5)

∂⁡σg/∂⁡p, derivative of the gap electrical conductance with respect to the pressure between the bodies. If the gap electrical conductance is not a function of the pressure, SIGMA(5)= 0.0. This variable needs to be defined only for a fully coupled thermal-electrical-structural analysis.

Variables passed in for information

D(1)

Separation between the interface surfaces, d.

D(2)

Pressure transmitted across the surfaces, p.

TEMP(2)

Current temperature at points A and B.

PREDEF(2,NPRED)

An array containing pairs of values of all of the user-specified field variables at the end of the current increment at points A and B (initial values at the beginning of the analysis and current values during the analysis).

TIME(1)

Value of step time at the end of the increment.

TIME(2)

Value of total time at the end of the increment.

CINAME

User-specified surface interaction name, left justified.

SLNAME

Slave surface name.

MSNAME

Master surface name.

COORDS

An array containing the current coordinates of points A and B. COORDS(1,K1) are the coordinates at point A, and COORDS(2,K1) are the coordinates at point B.

NODE

Slave node number (point A).

NPRED

Number of predefined field variables.

KSTEP

Step number.

KINC

Increment number.